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1509.01950
|
in this paper , we study the response of 2d framed structures made of rectangular cells , to the sudden removal of columns . we employ a simulation algorithm based on the discrete element method , where the structural elements are represented by elasto - plastic euler bernoulli beams with elongation - rotation failure threshold . the effect of structural cell slenderness and of topological hierarchy on the dynamic residual strength after damage @xmath0 is investigated . topologically _ hierarchical _ frames have a primary structure made of few massive elements , while _ homogeneous _ frames are made of many thin elements . we also show how @xmath0 depends on the activated collapse mechanisms , which are determined by the mechanical hierarchy between beams and columns , i.e. by their relative strength and stiffness . finally , principles of robustness - oriented capacity design which seem to be in contrast to the conventional anti - seismic capacity design are addressed . * keywords : * frames , progressive collapse , robustness , hierarchy
| 174
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cond-mat0207236
|
a feedback mechanism that involves the proteins p53 and mdm2 , induces cell death as a controled response to severe dna damage . a minimal model for this mechanism demonstrates that the respone may be dynamic and connected with the time needed to translate the mdm2 protein . the response takes place if the dissociation constant @xmath0 between p53 and mdm2 varies from its normal value . although it is widely believed that it is an increase in @xmath0 that triggers the response , we show that the experimental behaviour is better described by a decrease in the dissociation constant . the response is quite robust upon changes in the parameters of the system , as required by any control mechanism , except for few weak points , which could be connected with the onset of cancer . pacs : 87.16.yc
| 141
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cond-mat9702243
|
we investigate phase transitions in the ising model and the annni model in transverse field using the interface approach . the exact result of the ising chain in a transverse field is reproduced . we find that apart from the interfacial energy , there are two other response functions which show simple scaling behaviour . for the annni model in a transverse field , the phase diagram can be fully studied in the region where a ferromagnetic to paramagnetic phase transition occurs . the other region can be studied partially ; the boundary where the antiphase vanishes can be estimated . pacs nos . : 64.60.cn,75.10.jm,75.30.kz
| 106
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1512.02303
|
this article presents a general multivariate @xmath0-sensitivity index , rooted in the @xmath0-divergence between the unconditional and conditional probability measures of a stochastic response , for global sensitivity analysis . unlike the variance - based sobol index , the @xmath0-sensitivity index is applicable to random input following dependent as well as independent probability distributions . since the class of @xmath0-divergences supports a wide variety of divergence or distance measures , a plethora of @xmath0-sensitivity indices are possible , affording diverse choices to sensitivity analysis . commonly used sensitivity indices or measures , such as mutual information , squared - loss mutual information , and borgonovo s importance measure , are shown to be special cases of the proposed sensitivity index . new theoretical results , revealing fundamental properties of the @xmath0-sensitivity index and establishing important inequalities , are presented . three new approximate methods , depending on how the probability densities of a stochastic response are determined , are proposed to estimate the sensitivity index . four numerical examples , including a computationally intensive stochastic boundary - value problem , illustrate these methods and explain when one method is more relevant than the others . borgonovo s importance measure , @xmath0-sensitivity index , kernel density estimation , mutual information , polynomial dimensional decomposition , squared - loss mutual information .
| 220
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hep-lat0501014
|
this paper presents a first study of the decay constants of the charged , or flavor - off - diagonal , pseudoscalar mesons to two loops for three flavors of sea quarks , in partially quenched chiral perturbation theory ( pq@xmath0pt ) . explicit analytical expressions up to @xmath1 in the momentum expansion are given . the calculations have been performed within the supersymmetric formulation of pq@xmath0pt . we also present some numerical results to indicate the size of the corrections . lu tp 05 - 1 + hep - lat/0501014 + january 2005 * decay constants of pseudoscalar mesons to two loops + in three - flavor partially quenched @xmath0pt * * johan bijnens and timo a. lhde * + department of theoretical physics , lund university , + slvegatan 14a , s 223 62 lund , sweden * abstract * : 12.38.gc , 12.39.fe , 11.30.rd
| 148
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astro-ph0508020
|
large volumes of ccd imaging data that will become available from wide - field cameras at telescopes such as the cfht , subaru , vst , or vista in the near future are highly suitable for systematic _ distance surveys of early - type galaxies _ using the surface brightness fluctuation ( sbf ) method . for the efficient processing of such large data sets , we are developing the first semi - automatic sbf analysis pipeline named sapac . after a brief description of the sbf method we discuss the image quality needed for a successful distance measurement and give some background information on sapac .
| 107
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cond-mat0406099
|
the bcs - bec crossover is studied in a systematic way in the broken - symmetry phase between zero temperature and the critical temperature . this study bridges two regimes where quantum and thermal fluctuations are , respectively , important . the theory is implemented on physical grounds , by adopting a fermionic self - energy in the broken - symmetry phase that represents fermions coupled to superconducting fluctuations in weak coupling and to bosons described by the bogoliubov theory in strong coupling . this extension of the theory beyond mean field proves important at finite temperature , to connect with the results in the normal phase . the order parameter , the chemical potential , and the single - particle spectral function are calculated numerically for a wide range of coupling and temperature . this enables us to assess the quantitative importance of superconducting fluctuations in the broken - symmetry phase over the whole bcs - bec crossover . our results are relevant to the possible realizations of this crossover with high - temperature cuprate superconductors and with ultracold fermionic atoms in a trap .
| 186
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hep-ex0412033
|
from the famous experiments of stern and gerlach to the present , measurements of magnetic dipole moments , and searches for electric dipole moments of `` elementary '' particles have played a major role in our understanding of sub - atomic physics . in this talk i discuss the progress on measurements and theory of the magnetic dipole moment of the muon . i also discuss a new proposal to search for a permanent electric dipole moment ( edm ) of the muon and put it into the more general context of other edm searches . these experiments , along with searches for the lepton flavor violating decays @xmath0 and @xmath1 , provide a path to the high - energy frontier through precision measurements .
| 125
|
1202.1191
|
we apply the global mode analysis , which has been recently developed for the modeling of khz quasi - periodic oscillations ( qpos ) from neutron stars , to the inner region of an accretion disk around a rotating black hole . within a pseudo - newtonian approach that keeps the ratio of the radial epicyclic frequency @xmath0 to the orbital frequency @xmath1 the same as the corresponding ratio for a kerr black hole we determine the innermost disk region where the hydrodynamic modes grow in amplitude . we find that the radiation flux emerging from the inner disk has the highest values within the same region . using the flux weighted averages of the frequency bands over this region we identify the growing modes with highest frequency branches @xmath2 and @xmath3 to be the plausible candidates for the high - frequency qpo pairs observed in black hole systems . the observed frequency ratio around @xmath4 can therefore be understood naturally in terms of the global free oscillations in the innermost region of a viscous accretion disk around a black hole without invoking a particular resonance to produce black hole qpos . although the frequency ratio @xmath5/@xmath6 is found to be not sensitive to the black hole s spin which is good for explaining the high - frequency qpos it may work as a limited diagnostic of the spin parameter to distinguish black holes with very large spin from the slowly rotating ones . within our model we estimate the frequency ratio of a high - frequency qpo pair to be greater than @xmath4 if the black hole is a slow rotator . for fast rotating black holes , we expect the same ratio to be less than @xmath4 .
| 290
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1003.0669
|
we study the generation of small neutrino masses in an extra - dimensional model , where singlet fermions are allowed to propagate in the extra dimension , while the standard model particles are confined to a brane . motivated by the fact that extra - dimensional models are non - renormalizable , we truncate the kaluza klein towers at a maximal kaluza klein number . this truncation , together with the structure of the bulk majorana mass term , motivated by the sherk schwarz mechanism , implies that the kaluza klein modes of the singlet fermions pair to form dirac fermions , except for a number of unpaired majorana fermions at the top of each tower . these heavy majorana fermions are the only sources of lepton number breaking in the model , and similarly to the type - i seesaw mechanism , they naturally generate small masses for the left - handed neutrinos . the lower kaluza klein modes mix with the light neutrinos , and the mixing effects are not suppressed with respect to the light - neutrino masses . compared to conventional fermionic seesaw models , such mixing can be more significant . we study the signals of this model at the large hadron collider , and find that the current low - energy bounds on the non - unitarity of the leptonic mixing matrix are strong enough to exclude an observation .
| 236
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0906.3163
|
the study of phase structure of dilute @xmath0he - @xmath1he solid mixture of different quality is performed by spin echo nmr technique . the diffusion coefficient is determined for each coexistent phase . two diffusion processes are observed in rapidly quenched ( non - equilibrium ) hcp samples : the first process has a diffusion coefficient corresponding to hcp phase , the second one has huge diffusion coefficient corresponding to liquid phase . that is evidence of liquid - like inclusions formation during fast crystal growing . it is established that these inclusions disappear in equilibrium crystals after careful annealing . pacs numbers : 61.72.cc , 66.30.ma , 61.50.-f , 64.70.d- keywords : nmr , @xmath0he-@xmath1he solid mixture , diffusion , defects * * + _ ye.o . vekhov , a.p . birchenko , n.p . mikhin , and e.ya . rudavskii _ + _ _
| 146
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astro-ph9811173
|
the vlt on cerro paranal was used to observe four fields located at @xmath0 from the center of the galactic globular cluster ngc6712 in the v and r bands . the resulting color - magnitude diagram shows a well defined main sequence reaching down to the @xmath1 detection limit at @xmath2 , @xmath3 or approximately 4 magnitudes below the main sequence turn - off , the deepest obtained so far on this cluster . this yields a main sequence luminosity function that peaks at @xmath4 and drops down to the 50% completeness limit at @xmath5 . transformation to a mass function via the latest mass - luminosity relation appropriate to this object indicates that the peak of the luminosity function corresponds to @xmath6m@xmath7 , a value significantly higher than the @xmath8m@xmath7 , measured for most other clusters observed so far . since this object , in its galactic orbit , penetrates very deeply into the galactic bulge with perigalactic distance of @xmath9kpc , this result is the first strong evidence that tidal forces have stripped this cluster of a substantial portion of its lower mass star population all the way down to its half - light radius and possibly beyond .
| 201
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quant-ph0506259
|
in quantum information processing by nmr one of the major challenges is relaxation or decoherence . often it is found that the equilibrium mixed state of a spin system is not suitable as an initial state for computation and a definite initial state is required to be prepared prior to the computation . as these preferred initial states are non - equilibrium states , they are not stationary and are destroyed with time as the spin system relaxes toward its equilibrium , introducing error in computation . since it is not possible to cut off the relaxation processes completely , attempts are going on to develop alternate strategies like quantum error correction codes or noiseless subsystems . here we study the relaxation behavior of various pseudo pure states and analyze the role of cross terms between different relaxation processes , known as cross - correlation . it is found that while cross - correlations accelerate the relaxation of certain pseudo pure states , they retard that of others .
| 169
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astro-ph0408030
|
the discovery of the microquasar ls 5039 well within the 95% conficence contour of the unidentified egret source ( ues ) 3eg j1824@xmath01514 was a major step towards the possible association between microquasars ( mqs ) and uess . the recent discovery of precessing relativistic radio jets in ls i + 61 303 , a source associated for long time with 2cg 135 + 01 and with the ues 3eg j0241 + 6103 , has given further support to this idea . finally , the very recently proposed association between the microquasar candidate ax j1639.0@xmath04642 and the ues 3eg j1639@xmath04702 points towards a population of high mass x - ray binary ( hmxb)/neutron star ( ns ) microquasars as counterparts of low - latitude unidentified egret sources . marc rib + service dastrophysique + cea saclay + bt . 709 , lorme des merisiers + f-91191 gif - sur - yvette , cedex + france
| 155
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astro-ph9606116
|
we investigate the clustering properties of loose groups in the perseus pisces redshift survey . previous analyses based on cfa and ssrs surveys led to apparently contradictory results . we investigate the source of such discrepancies , finding satisfactory explanations for them . furthermore , we find a definite signal of group clustering , whose amplitude @xmath0 exceeds the amplitude @xmath1 of galaxy clustering ( @xmath2 , @xmath3 for the most significant case ; distances are measured in @xmath4 ) . groups are identified with the adaptive friends of friends ( fof ) algorithms hg ( huchra & geller 1982 ) and nw ( nolthenius & white 1987 ) , systematically varying all search parameters . correlation strenght is especially sensitive to the sky link @xmath5 ( increasing for stricter normalization @xmath6 ) , and to the ( depth @xmath7 of the ) galaxy data . it is only moderately dependent on the galaxy luminosity function @xmath8 , while it is almost insensitive to the redshift link @xmath9 ( both to the normalization @xmath10 and to the scaling recipes hg or nw ) .
| 184
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1504.06996
|
we study , both theoretically and experimentally , modulational instability in optical fibers that have a longitudinal evolution of their dispersion in the form of a dirac delta comb . by means of floquet theory , we obtain an exact expression for the position of the gain bands , and we provide simple analytical estimates of the gain and of the bandwidths of those sidebands . an experimental validation of those results has been realized in several microstructured fibers specifically manufactured for that purpose . the dispersion landscape of those fibers is a comb of gaussian pulses having widths much shorter than the period , which therefore approximate the ideal dirac comb . experimental spontaneous mi spectra recorded under quasi continuous wave excitation are in good agreement with the theory and with numerical simulations based on the generalized nonlinear schrdinger equation .
| 142
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1304.7565
|
we study the dynamics of spin-1 atoms in a periodic optical - lattice potential and an external magnetic field in a quantum quench scenario where we start from a superfluid ground state in a shallow lattice potential and suddenly raise the lattice depth . the time evolution of the non - equilibrium state , thus created , shows collective collapse - and - revival oscillations of matter - wave coherence as well as oscillations in the spin populations . we show that the complex pattern of these two types of oscillations reveals details about the superfluid and magnetic properties of the initial many - body ground state . furthermore , we show that the strengths of the spin - dependent and spin - independent atom - atom interactions can be deduced from the observations . the hamiltonian that describes the physics of the final deep lattice not only contains two - body interactions but also effective multi - body interactions , which arise due to virtual excitations to higher bands . we derive these effective spin - dependent three - body interaction parameters for spin-1 atoms and describe how spin - mixing is affected . spinor atoms are unique in the sense that multi - body interactions are directly evident in the _ in - situ _ number densities in addition to the momentum distributions . we treat both antiferromagnetic ( e.g. @xmath0na atoms ) and ferromagnetic ( e.g. @xmath1rb and @xmath2k ) condensates .
| 245
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astro-ph9806180
|
the effect of rotation on the cooling of neutron stars is investigated . the thermal evolution equations are solved in two dimensions with full account of general relativistic effects . it is found that rotation is particularly important in the early epoch when the neutron star s interior is not yet isothermal . the polar surface temperature is up to 63% higher than the equatorial temperature . this temperature difference might be observable if the thermal radiation of a young , rapidly rotating neutron star is detected . in the intermediate epoch ( @xmath0 yr ) , when the interior becomes isothermal , the polar temperature is still up to 31% higher than the equatorial temperature . afterwards photon surface radiation dominates the cooling , and the surface becomes isothermal on a timescale of @xmath1 yr . furthermore , the transition between the early and the intermediate epochs is delayed by several hundred years . an additional effect of rotation is the reduction of the neutrino luminosity due to the reduction of the central density with respect to the non - rotating case .
| 184
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hep-ph0601142
|
we investigate the tev - scale stringy signals of the four - fermion scattering at the electron - positron collider with the center of mass energy @xmath0 gev . the nature of the stringy couplings leads to distinguishable asymmetries comparing to the other new physics models . specifically , the stringy states in the four - fermion scattering at the leading - order corrections are of spin-1 and 2 with the chiral couplings inherited from the gauge bosons identified as the zeroth - mode string states . the angular left - right , forward - backward , center - edge asymmetries and the corresponding polarized - beam asymmetries are investigated . the low - energy stringy corrections are compared to the ones induced by the kaluza - klein ( kk ) gravitons . the angular left - right asymmetry of the scattering with the final states of @xmath1 and @xmath2-type quarks , namely @xmath3 and @xmath4 , shows significant deviations from the standard model values . the center - edge and forward - backward asymmetries for all final - states fermions also show significant deviations from the corresponding standard model values . the differences between the signatures induced by the stringy corrections and the kk gravitons are appreciable in both angular left - right and forward - backward asymmetries . @xmath5 0.4 cm
| 223
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gr-qc0205102
|
we perform some numerical study of the secular triaxial instability of rigidly rotating homogeneous fluid bodies in general relativity . in the newtonian limit , this instability arises at the bifurcation point between the maclaurin and jacobi sequences . it can be driven in astrophysical systems by viscous dissipation . we locate the onset of instability along several constant baryon mass sequences of uniformly rotating axisymmetric bodies for compaction parameter @xmath0 . we find that general relativity weakens the jacobi like bar mode instability , but the stabilizing effect is not very strong . according to our analysis the critical value of the ratio of the kinetic energy to the absolute value of the gravitational potential energy @xmath1 for compaction parameter as high as @xmath2 is only @xmath3 higher than the newtonian value . the critical value of the eccentricity depends very weakly on the degree of relativity and for @xmath4 is only @xmath5 larger than the newtonian value at the onset for the secular bar mode instability . we compare our numerical results with recent analytical investigations based on the post - newtonian expansion .
| 186
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1405.3625
|
richardson s theory of turbulent particle pair diffusion [ richardson , l. f. proc . roy . soc . lond . a 100 , 709737 , 1926 ] , based upon observational data , is equivalent to a locality hypothesis in which the turbulent pair diffusivity @xmath0 scales with the pair separation @xmath1 with a 4/3-power law , @xmath2 . here , a reappraisal of the 1926 dataset reveals that one of the data - points is from a molecular diffusion context ; the remaining data from geophysical turbulence display an unequivocal non - local scaling , @xmath3 . consequently , the foundations of pair diffusion theory have been re - examined , leading to a new theory based upon the principle that both local and non - local diffusional processes govern pair diffusion in homogeneous turbulence . through a novel mathematical approach the theory is developed in the context of generalised power law energy spectra , @xmath4 for @xmath5 , over extended inertial subranges . the theory predicts the scaling , @xmath6 , with @xmath7 intermediate between the purely local and the purely non - local scalings , i.e. @xmath8 . a lagrangian diffusion model , kinematic simulations [ kraichnan , r. h. , phys . fluids 13 , 22 - 31 , 1970 ; fung et al . , j. fluid mech . 236 , 281 - 318 , 1992 ] , is used to examine the predictions of the new theory all of which are confirmed . the simulations produce the scalings , @xmath9 to @xmath10 , in the accepted range of intermittent turbulence spectra , @xmath11 to @xmath12 , in close agreement with the revised 1926 dataset . turbulence , pair diffusion , richardson , non - local , mathematical foundations , simulation
| 297
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1609.09640
|
we report the coexistence and properties of stable compact localized states ( clss ) and discrete solitons ( dss ) for nonlinear spinor waves on a flatband network with spin - orbit coupling ( soc ) . the system can be implemented by means of a binary bose - einstein condensate loaded in the corresponding optical lattice . in the linear limit , the soc opens a minigap between flat and dispersive bands in the system s bandgap structure , and preserves the existence of clss at the flatband frequency , simultaneously lowering their symmetry . adding onsite cubic nonlinearity , the clss persist and remain available in an exact analytical form , with frequencies which are smoothly tuned into the minigap . inside of the minigap , the cls and ds families are stable in narrow areas adjacent to the fb . deep inside the semi - infinite gap , both the clss and dss are stable too .
| 160
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1612.04066
|
we study the dynamics caused by transport of transverse magnetization in one dimensional transverse ising chain at zero temperature . we observe that a class of initial states in fermionic momentum - space produce spatial variation in transverse magnetization . starting from such a state , we obtain the transverse magnetization analytically and then observe its dynamics in presence of a homogeneous constant field @xmath0 . in contradiction with general expectation , whatever be the strength of the field , the magnetization of the system does not become homogeneous even after infinite time . in each site , the dynamics is associated with oscillations having two different timescales . the envelope of the larger timescale oscillation decays algebraically having an exponent which is universal for the entire class of such initial states . signature of quantum criticality is also embedded in the dynamics in two aspects : behavioral change shown by the frequency of large timescale oscillation at any site and the corresponding magnetization at infinity when they cross the quantum critical point .
| 174
|
1002.0127
|
we propose and analyze a multi - functional setup consisting of high finesse optical cavities , beam splitters , and phase shifters . the basic scheme projects arbitrary photonic two - mode input states onto the subspace spanned by the product of fock states @xmath0 with @xmath1 . this protocol does not only provide the possibility to conditionally generate highly entangled photon number states as resource for quantum information protocols but also allows one to test and hence purify this type of quantum states in a communication scenario , which is of great practical importance . the scheme is especially attractive as a generalization to many modes allows for distribution and purification of entanglement in networks . in an alternative working mode , the setup allows of quantum non demolition number resolved photodetection in the optical domain .
| 138
|
1009.3966
|
we investigate zero sound in @xmath0-dimensional effective holographic theories , whose action is given by einstein - maxwell - dilaton terms . the bulk spacetimes include both zero temperature backgrounds with anisotropic scaling symmetry and their near - extremal counterparts obtained in 1006.2124 [ hep - th ] , while the massless charge carriers are described by probe d - branes . we discuss thermodynamics of the probe d - branes analytically . in particular , we clarify the conditions under which the specific heat is linear in the temperature , which is a characteristic feature of fermi liquids . we also compute the retarded green s functions in the limit of low frequency and low momentum and find quasi - particle excitations in certain regime of the parameters . the retarded green s functions are plotted at specific values of parameters in @xmath1 , where the specific heat is linear in the temperature and the quasi - particle excitation exists . we also calculate the ac conductivity in @xmath0-dimensions as a by - product . cquest-2010 - 0395 * zero sound in effective holographic theories * bum - hoon lee@xmath2 , da - wei pang@xmath3 and chanyong park@xmath3 + _ seoul 121 - 742 , korea + _ _ @xmath4 center for quantum spacetime , sogang university _ + _ seoul 121 - 742 , korea + _ bhl@sogang.ac.kr , pangdw@sogang.ac.kr , cyong21@sogang.ac.kr
| 234
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hep-ph0602092
|
we review recent progress of understanding and resolving instabilities driven by mismatch between the fermi surfaces of the pairing quarks in 2-flavor color superconductor . with the increase of mismatch , the 2sc phase exhibits chromomagnetic instability as well as color neutral baryon current instability . we describe the 2sc phase in the nonlinear realization framework , and show that each instability indicates the spontaneous generation of the corresponding pseudo nambu - golstone current . the nambu - goldstone currents generation state covers the gluon phase as well as the one - plane wave loff state . we further point out that , when charge neutrality condition is required , there exists a narrow unstable loff ( us - loff ) window , where not only off - diagonal gluons but the diagonal 8-th gluon can not avoid the magnetic instability . in this us - loff window , the diagonal magnetic instability can not be cured by off - diagonal gluon condensate in the color superconducting phase .
| 169
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quant-ph0604075
|
the knowledge of quantum phase flow induced under the weyl s association rule by the evolution of heisenberg operators of canonical coordinates and momenta allows to find the evolution of symbols of generic heisenberg operators . the quantum phase flow curves obey the quantum hamilton s equations and play the role of characteristics . at any fixed level of accuracy of semiclassical expansion , quantum characteristics can be constructed by solving a coupled system of first - order ordinary differential equations for quantum trajectories and generalized jacobi fields . classical and quantum constraint systems are discussed . the phase - space analytic geometry based on the star - product operation can hardly be visualized . the statement `` quantum trajectory belongs to a constraint submanifold '' can be changed e.g. to the opposite by a unitary transformation . some of relations among quantum objects in phase space are , however , left invariant by unitary transformations and support partly geometric relations of belonging and intersection . quantum phase flow satisfies the star - composition law and preserves hamiltonian and constraint star - functions .
| 184
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1405.2387
|
in this paper , we consider a multi - cell multi - user miso broadcast channel . the system operates according to the opportunistic beamforming framework in a multi - cell environment with variable number of transmit beams ( may alternatively be referred as the transmission rank ) at each base station . the maximum number of co - scheduled users in a cell is equal to its transmission rank , thus increasing it will have the effect of increasing the multiplexing gain . however , this will simultaneously increase the amount of interference in the network , which will decrease the rate of communication . this paper focuses on optimally setting the transmission rank at each base station such that a set of quality of service ( qos ) constraints , that will ensure a guaranteed minimum rate per beam at each base station , is not violated . expressions representing the achievable region of transmission ranks are obtained considering different network settings . the achievable transmission rank region consists of all achievable transmission rank tuples that satisfy the qos constraints . numerical results are also presented to provide further insights on the feasibility problem .
| 197
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0910.5627
|
sciboone , located in the booster neutrino beam at fermilab , collected data from june 2007 to august 2008 to accurately measure muon neutrino and anti - neutrino cross sections on carbon below 1 gev neutrino energy . sciboone is studying charged current interactions . among them , neutral pion production interactions will be the focus of this poster . the experimental signature of neutrino - induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the @xmath0 decay photons , with an additional muon in the final state for cc processes . in this poster , i will present how we reconstruct and select charged - current muon neutrino interactions producing @xmath0 s in sciboone address = ific ( u. valencia / csic )
| 130
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math0408411
|
we show how to orient moduli spaces of holomorphic disks with boundary on an exact lagrangian immersion of a spin manifold into complex @xmath0-space in a coherent manner . this allows us to lift the coefficients of the contact homology of legendrian spin submanifolds of standard contact @xmath1-space from @xmath2 to @xmath3 we demonstrate how the @xmath4-lift provides a more refined invariant of legendrian isotopy . we also apply contact homology to produce lower bounds on double points of certain exact lagrangian immersions into @xmath5 and again including orientations strengthens the results . more precisely , we prove that the number of double points of an exact lagrangian immersion of a closed manifold @xmath6 whose associated legendrian embedding has good dga is at least half of the dimension of the homology of @xmath6 with coefficients in an arbitrary field if @xmath6 is spin and in @xmath2 otherwise .
| 148
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1405.4187
|
the astri project aims to develop , in the framework of the cherenkov telescope array , an end - to - end prototype of the small - size telescope , devoted to the investigation of the energy range @xmath0 1100 tev . the proposed design is characterized by two challenging but innovative technological solutions which will be adopted for the first time on a cherenkov telescope : a dual - mirror schwarzschild couder configuration and a modular , light and compact camera based on silicon photo - multipliers . here we describe the prototype design , the expected performance and the possibility to realize a mini array composed by a few such telescopes , which shall be placed at the final cta southern site .
| 125
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1512.08725
|
we propose experimental verification and theoretical explanation of magnetic anomalies in the complex fe - contained double perovskite multiferroics like pbfe@xmath0nb@xmath0o@xmath1 . the theoretical part is based on our model of coexistence of long - range magnetic order and spin glass in the above substances . in our model , the exchange interaction is anisotropic , coupling antiferromagnetically @xmath2 spin components of fe@xmath3 ions . at the same time , the @xmath4 components are coupled by much weaker exchange interaction of ferromagnetic sign . in the system with spatial disorder ( half of corresponding lattice cites are occupied by spinless nb@xmath5 ions ) such frustrating interaction results in the fact that antiferromagnetic order is formed by @xmath2 projection of the spins , while their @xmath4 components contribute to spin glass behaviour . our theoretical findings are supported by the experimental evidence of coexistence of antiferromagnetic and spin glass phases in chemically disordered fe - contained double perovskite multiferroics .
| 159
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cond-mat9501025
|
we consider the problem of the statistics of the scattering matrix @xmath0 of a chaotic cavity ( quantum dot ) , which is coupled to the outside world by non - ideal leads containing @xmath1 scattering channels . the hamiltonian @xmath2 of the quantum dot is assumed to be an @xmath3 hermitian matrix with probability distribution @xmath4^{-(\beta m + 2 - \beta)/2}$ ] , where @xmath5 and @xmath6 are arbitrary coefficients and @xmath7 depending on the presence or absence of time - reversal and spin - rotation symmetry . we show that this `` lorentzian ensemble '' agrees with microscopic theory for an ensemble of disordered metal particles in the limit @xmath8 , and that for any @xmath9 it implies @xmath10 is the ensemble average of @xmath0 . this `` poisson kernel '' generalizes dyson s circular ensemble to the case @xmath11 and was previously obtained from a maximum entropy approach . the present work gives a microscopic justification for the case that the chaotic motion in the quantum dot is due to impurity scattering .
| 176
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quant-ph0703138
|
quantum mechanical entanglement can exist in noisy open quantum systems at high temperature . a simple mechanism , where system particles are randomly reset to some standard initial state , can counteract the deteriorating effect of decoherence , resulting in an entangled steady state far from thermodynamical equilibrium . we present models for both gas - type systems and for strongly coupled systems . we point out in which way the entanglement resulting from such a reset mechanism is different from the entanglement that one can find in thermal states . we develop master equations to describe the system and its interaction with an environment , study toy models with two particles ( qubits ) , where the master equation can often be solved analytically , and finally examine larger systems with possibly fluctuating particle numbers . we find that in gas - type systems , the reset mechanism can produce an entangled steady state for an arbitrary temperature of the environment , while this is not true in strongly coupled systems . but even then , the temperature range where one can find entangled steady states is typically much higher with the reset mechanism .
| 196
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1305.7022
|
for two - dimensional many - particle systems first - order , second - order , single step continuous , as well as two - step continuous ( kthny - like ) melting transitions have been found in previous studies . recent computer simulations , using particle numbers in the @xmath0 range , as well as a few experimental studies , tend to support the two - step scenario , where the solid and liquid phases are separated by a third , so called hexatic phase . we have performed molecular dynamics simulations on yukawa ( debye - hckel ) systems at conditions earlier predicted to belong to the hexatic phase . our simulation studies on the time needed for the equilibration of the systems conclude that the hexatic phase is metastable and disappears in the limit of long times . we also show that simply increasing the particle number in particle simulations does not necessarily result in more accurate conclusions regarding the existence of the hexatic phase . the increase of the system size has to be accompanied with the increase of the simulation time to ensure properly thermalized conditions .
| 192
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1412.7513
|
we survey the role of symmetry in diffeomorphic registration of landmarks , curves , surfaces , images and higher - order data . the infinite dimensional problem of finding correspondences between objects can for a range of concrete data types be reduced resulting in compact representations of shape and spatial structure . this reduction is possible because the available data is incomplete in encoding the full deformation model . using reduction by symmetry , we describe the reduced models in a common theoretical framework that draws on links between the registration problem and geometric mechanics . symmetry also arises in reduction to the lie algebra using particle relabeling symmetry allowing the equations of motion to be written purely in terms of eulerian velocity field . reduction by symmetry has recently been applied for jet - matching and higher - order discrete approximations of the image matching problem . we outline these constructions and further cases where reduction by symmetry promises new approaches to registration of complex data types .
| 169
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hep-ph0209323
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cern measurements of @xmath0 on polarized target at 17.2 gev / c enable experimental determination of partial wave production amplitudes below 1080 mev . the measured @xmath1-wave transversity amplitudes provide evidence for a narrow scalar resonance @xmath2 . the assumption of analyticity of production amplitudes in dipion mass allows to determine @xmath1-wave helicity amplitudes @xmath3 and @xmath4 . the helicity flip amplitude @xmath4 is related to @xmath5 scattering . there are four `` down '' solutions @xmath6 , @xmath7 , @xmath8 and @xmath9 selected by the unitarity in @xmath5 scattering . ellis - lanik relation between the mass @xmath10 and partial width @xmath11 derived from an effective qcd theory with broken scale and chiral symmetry selects solutions @xmath6 and @xmath8 and imparts the @xmath2 resonance with a dilaton - gluonium interpretation . weinberg s mended symmetry selects solutions @xmath6 and @xmath7 . the combined solution @xmath6 has @xmath12 mev and @xmath13 mev . the observed @xmath14 degeneracy leads to new relations between gluon condensate and pion decay constant and @xmath15 chiral condensate . the two relations are well satisfied . ellis - lanik relation relates the existence of @xmath2 to breaking of scale symmetry in qcd . interaction of chirally invariant and narrow @xmath2 with chirally noninvariant qcd vacuum in @xmath5 scattering is proposed as a possible mechanism for the metamorphosis of @xmath2 into a broad resonant @xmath1-wave structure in @xmath5 related to spontaneous breaking of chiral symmetry in qcd . we comment on possible connections of @xmath2 to cosmological contstant and qcd / string duality in ads / cft brane world model .
| 264
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1503.03516
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we present a study on the effect of undetected stellar companions on the derived planetary radii for the kepler objects of interest ( kois ) . the current production of the koi list assumes that the each koi is a single star . not accounting for stellar multiplicity statistically biases the planets towards smaller radii . the bias towards smaller radii depends on the properties of the companion stars and whether the planets orbit the primary or the companion stars . defining a planetary radius correction factor @xmath0 , we find that if the kois are assumed to be single , then , _ on average _ , the planetary radii may be underestimated by a factor of @xmath1 . if typical radial velocity and high resolution imaging observations are performed and no companions are detected , this factor reduces to @xmath2 . the correction factor @xmath3 is dependent upon the primary star properties and ranges from @xmath4 for a and f stars to @xmath5 for k and m stars . for missions like k2 and tess where the stars may be closer than the stars in the kepler target sample , observational vetting ( primary imaging ) reduces the radius correction factor to @xmath6 . finally , we show that if the stellar multiplicity rates are not accounted for correctly , occurrence rate calculations for earth - sized planets may overestimate the frequency of small planets by as much as @xmath7% .
| 243
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1605.02348
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a configuration space method is developed for binding energy calculations of the lowest energy exciton complexes ( trion , biexciton ) in spatially confined quasi-1d semiconductor nanostructures such as nanowires and nanotubes . quite generally , trions are shown to have greater binding energy in strongly confined structures with small reduced electron - hole masses . biexcitons have greater binding energy in less confined structures with large reduced electron - hole masses . this results in a universal crossover behavior , whereby trions become less stable than biexcitons as the transverse size of the quasi-1d nanostructure increases . the method is also capable of evaluating binding energies for electron - hole complexes in quasi-2d semiconductors such as coupled quantum wells and bilayer van der walls bound heterostructures with advanced optoelectronic properties .
| 132
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1204.2694
|
we developed a model for the enhancement of the heat flux by spherical and elongated nano - particles in sheared laminar flows of nano - fluids . besides the heat flux carried by the nanoparticles the model accounts for the contribution of their rotation to the heat flux inside and outside the particles . the rotation of the nanoparticles has a twofold effect , it induces a fluid advection around the particle and it strongly influences the statistical distribution of particle orientations . these dynamical effects , which were not included in existing thermal models , are responsible for changing the thermal properties of flowing fluids as compared to quiescent fluids . the proposed model is strongly supported by extensive numerical simulations , demonstrating a potential increase of the heat flux far beyond the maxwell - garnet limit for the spherical nanoparticles . the road ahead which should lead towards robust predictive models of heat flux enhancement is discussed .
| 160
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0809.2128
|
nuclear reactors have served as the antineutrino source for many fundamental physics experiments . the techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose . the large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards : the reactor power and fissile inventory . measurements made with antineutrino detectors could therefore offer an alternative means for verifying the power history and fissile inventory of a reactors , as part of international atomic energy agency ( iaea ) and other reactor safeguards regimes . several efforts to develop this monitoring technique are underway across the globe .
| 113
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1610.04980
|
the modes of silicon disk meta - atoms are investigated , motivated by their use as a building block of huygens metasurfaces . a model based on these modes gives a clear physical explanation of all features in the extinction spectrum , in particular due to the interference between non - orthogonal modes . by performing a vector spherical harmonic expansion of each mode , the complex features of the far - field scattering spectrum are also readily explained . it is shown that in general each mode has contributions from many multipole moments . higher order modes with appropriate symmetry are also able to satisfy the huygens condition , leading to multiple bands of strong forward scattering and suppressed back scattering . these results demonstrate a robust approach to find the modes of nano - photonic scatterers , commonly referred to as quasi - normal modes . by utilising an integral formulation of maxwell s equations , the problem of normalising diverging far - fields is avoided . the approach is implemented in an open - source code .
| 180
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1006.0169
|
we propose a new mechanism for the delivery of gas to the heart of galactic nuclei . we show that warm halo clouds must periodically impact galactic centers and potentially deliver a large ( @xmath0 ) mass of gas to the galactic nucleus in a singular event . the impact of an accreting warm halo cloud originating far in the galactic halo can , depending on mixing , produce a nuclear starburst of low metallicity stars as well as low luminosity accretion onto the central black hole . based on multiphase cooling around a @xmath1cdm distribution of halos we calculate the nuclear impact rate , the mass captured by the central black hole and the fraction of active nuclei for impacting cloud masses in the range @xmath2 . if there is moderate braking during cloud infall , our model predicts an average fraction of low luminosity active nuclei consistent with observations .
| 152
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nucl-th0212088
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the different kinds of behaviour of three - body systems in the weak binding limit are classified with specific attention to the transition from a true three - body system to an effective two - body system . for weakly bound borromean systems approaching the limit of binding we show that the size - binding energy relation is an almost universal function of the three @xmath0-wave scattering lengths measured in units of a hyperradial scaling parameter defined as a mass weighted average of two - body equivalent square well radii . we explain why three - body halos follow this curve and why systems appearing above reveal two - body substructures . three - body quantum halos 2 - 3 times larger than the limit set by zero hypermoment are possible .
| 132
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astro-ph0508232
|
we calculate in detail the expected properties of low redshift dlas under the assumption that they arise in the gaseous disks of galaxies like those in the @xmath0 population . a sample of 355 nearby galaxies is analysed , for which high quality hi 21-cm emission line maps are available as part of an extensive survey with the westerbork telescope ( whisp ) . we find that expected luminosities , impact parameters between quasars and dla host galaxies , and metal abundances are in good agreement with the observed properties of dlas and dla galaxies . the measured redshift number density of @xmath1 gas above the dla limit is @xmath2 , which compared to higher @xmath3 measurements implies that there is no evolution in the comoving density of dlas along a line of sight between @xmath4 and @xmath1 , and a decrease of only a factor of two from @xmath5 to the present time . we conclude that the local galaxy population can explain all properties of low redshift dlas . galaxies : ism ; ( galaxies : ) quasars : absorption lines ; galaxies : evolution
| 187
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1702.07673
|
fifth generation ( 5 g ) wireless networks face various challenges in order to support large - scale heterogeneous traffic and users , therefore new modulation and multiple access ( ma ) schemes are being developed to meet the changing demands . as this research space is ever increasing , it becomes more important to analyze the various approaches , therefore in this article we present a comprehensive overview of the most promising modulation and ma schemes for 5 g networks . we first introduce the different types of modulation that indicate their potential for orthogonal multiple access ( oma ) schemes and compare their performance in terms of spectral efficiency , out - of - band leakage , and bit - error rate . we then pay close attention to various types of non - orthogonal multiple access ( noma ) candidates , including power - domain noma , code - domain noma , and noma multiplexing in multiple domains . from this exploration we can identify the opportunities and challenges that will have significant impact on the design of modulation and ma for 5 g networks . 5 g , modulation , non - orthogonal multiple access .
| 200
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1111.3191
|
an analysis is made of the fine structure in the cosmic ray energy spectrum : new facets of present observations and their interpretation and the next step . it is argued that less than about 10% of the intensity of the helium ` peak ' at the knee at @xmath0 is due to just a few sources ( snr ) other than the single source . the apparent concavity in the rigidity spectra of protons and helium nuclei which have maximum curvature at about 200 gv is confirmed by a joint analysis of the pamela , cream and atic experiments . the spectra of heavier nuclei also show remarkable structure in the form of ` ankles ' at several hundred gev / nucleon . possible mechanisms are discussed . the search for ` pulsar peaks ' has not yet proved successful .
| 142
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1106.0560
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despite recent advances in uncovering the quantitative features of stationary human activity patterns , many applications , from pandemic prediction to emergency response , require an understanding of how these patterns change when the population encounters unfamiliar conditions . to explore societal response to external perturbations we identified real - time changes in communication and mobility patterns in the vicinity of eight emergencies , such as bomb attacks and earthquakes , comparing these with eight non - emergencies , like concerts and sporting events . we find that communication spikes accompanying emergencies are both spatially and temporally localized , but information about emergencies spreads globally , resulting in communication avalanches that engage in a significant manner the social network of eyewitnesses . these results offer a quantitative view of behavioral changes in human activity under extreme conditions , with potential long - term impact on emergency detection and response .
| 150
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astro-ph9810259
|
we present new @xmath0 photometry for the halo globular cluster m30 ( ngc 7099 = c2137 - 174 ) , and compute luminosity functions ( lfs ) in both bands for samples of about 15,000 hydrogen - burning stars from near the tip of the red giant branch ( rgb ) to over four magnitudes below the main - sequence ( ms ) turnoff . we confirm previously observed features of the lf that are at odds with canonical theoretical predictions : an excess of stars on subgiant branch ( sgb ) approximately 0.4 mag above the turnoff and an excess number of rgb stars relative to ms stars . based on subdwarfs with _ hipparcos_-measured parallaxes , we compute apparent distance moduli of @xmath1 and @xmath2 for reddenings of e@xmath3 and 0.02 respectively . the implied luminosity for the horizontal branch ( hb ) at these distances is @xmath4 and 0.37 mag . the two helium indicators we have been able to measure ( @xmath5 and @xmath6 ) both indicate that m30 s helium content is high relative to other clusters of similar metallicity . m30 has a larger value for the parameter @xmath7 than any of the other similarly metal - poor clusters for which this quantity can be reliably measured . this suggests that m30 has either a larger age or higher helium content than all of the other metal - poor clusters examined . the color - difference method for measuring relative ages indicates that m30 is coeval with the metal - poor clusters m68 and m92 . = -0.5 in epsf
| 266
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cond-mat0305065
|
dimer vacancy ( dv ) defect complexes in the si(001)@xmath0 surface were investigated using high - resolution scanning tunneling microscopy and first principles calculations . we find that under low bias filled - state tunneling conditions , isolated ` split - off ' dimers in these defect complexes are imaged as pairs of protrusions while the surrounding si surface dimers appear as the usual `` bean - shaped '' protrusions . we attribute this to the formation of @xmath1-bonds between the two atoms of the split - off dimer and second layer atoms , and present charge density plots to support this assignment . we observe a local brightness enhancement due to strain for different dv complexes and provide the first experimental confirmation of an earlier prediction that the 1 + 2-dv induces less surface strain than other dv complexes . finally , we present a previously unreported triangular shaped split - off dimer defect complex that exists at s@xmath2-type step edges , and propose a structure for this defect involving a bound si monomer .
| 176
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astro-ph0303314
|
we present a _ chandra _ observation of the central ( @xmath0 kpc ) region of the cluster of galaxies a , rich in interesting phenomena . on large scales ( @xmath1 kpc ) , the x - ray surface brightness is symmetric and slightly elliptical . the cluster has a cool dense core ; the radial temperature gradient varies with position angle . the radial metallicity profile shows a pronounced central drop and an off - center peak . similarly to many clusters with dense cores , a hosts a cold front at @xmath2 kpc south of the center . the gas pressure across the front is discontinuous by a factor @xmath3 , indicating that the cool core is moving with respect to the ambient gas with a mach number @xmath4 . the central dense region inside the cold front shows an unusual x - ray morphology , which consists of a number of x - ray blobs and/or filaments on scales @xmath5 kpc , along with two prominent x - ray cavities . the x - ray blobs are not correlated with either the optical line emission ( h@xmath6[nii ] ) , member galaxies or radio emission . deprojected temperature of the dense blobs is consistent with that of the less dense ambient gas , so these gas phases do not appear to be in thermal pressure equilibrium . an interesting possibility is a significant , unseen non - thermal pressure component in the inter - blob gas , possibly arising from the activity of the central agn . we discuss two models for the origin of the gas blobs hydrodynamic instabilities caused by the observed motion of the gas core , or `` bubbling '' of the core caused by multiple outbursts of the central agn .
| 300
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1703.02286
|
we investigate atom - based electric - field calibration and polarization measurement of a 100-mhz linearly polarized radio - frequency ( rf ) field using cesium rydberg - atom electromagnetically induced transparency ( eit ) in a room - temperature vapor cell . the calibration method is based on matching experimental data with the results of a theoretical floquet model . the utilized 60@xmath0 fine structure floquet levels exhibit @xmath1- and @xmath2-dependent ac stark shifts and splittings , and develop even - order rf - modulation sidebands . the floquet map of cesium 60@xmath0 fine structure states exhibits a series of exact crossings between states of different @xmath2 , which are not rf - coupled . these exact level crossings are employed to perform a rapid and precise ( @xmath3 ) calibration of the rf electric field . we also map out three series of narrow avoided crossings between fine structure floquet levels of equal @xmath2 and different @xmath1 , which are weakly coupled by the rf field via a raman process . the coupling leads to narrow avoided crossings that can also be applied as spectroscopic markers for rf field calibration . we further find that the line - strength ratio of intersecting floquet levels with different @xmath2 provides a fast and robust measurement of the rf field s polarization .
| 222
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0804.1790
|
in a previous paper we demonstrated that non - radial hydrodynamic oscillations of a thermally - supported ( bonnor - ebert ) sphere embedded in a low - density , high - temperature medium persist for many periods . the predicted column density variations and molecular spectral line profiles are similar to those observed in the bok globule b68 suggesting that the motions in some starless cores may be oscillating perturbations on a thermally supported equilibrium structure . such oscillations can produce molecular line maps which mimic rotation , collapse or expansion , and thus could make determining the dynamical state from such observations alone difficult . however , while b68 is embedded in a very hot , low - density medium , many starless cores are not , having interior / exterior density contrasts closer to unity . in this paper we investigate the oscillation damping rate as a function of the exterior density . for concreteness we use the same interior model employed in broderick et al . ( 2007 ) , with varying models for the exterior gas . we also develop a simple analytical formalism , based upon the linear perturbation analysis of the oscillations , which predicts the contribution to the damping rates due to the excitation of sound waves in the external medium . we find that the damping rate of oscillations on globules in dense molecular environments is always many periods , corresponding to hundreds of thousands of years , and persisting over the inferred lifetimes of the globules .
| 257
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0908.1673
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we present the first evidence of a retrograde orbit of the transiting exoplanet hat - p-7b . the discovery is based on a measurement of the rossiter - mclaughlin effect with the subaru hds during a transit of hat - p-7b , which occurred on ut 2008 may 30 . our best - fit model shows that the spin - orbit alignment angle of this planet is @xmath0 @xmath1 . the existence of such a retrograde planet have been predicted by recent planetary migration models considering planet - planet scattering processes or the kozai migration . our finding provides an important milestone that supports such dynamic migration theories .
| 109
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1009.2845
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we consider a loop mixing of two fermion fields of opposite parities whereas the parity is conserved in a lagrangian . such kind of mixing is specific for fermions and has no analogy in boson case . possible applications of this effect may be related with physics of baryon resonances . the obtained matrix propagator defines a pair of unitary partial amplitudes which describe the production of resonances of spin @xmath0 and different parity @xmath1 or @xmath2 . + the use of our amplitudes for joint description of @xmath3 partial waves @xmath4 and @xmath5 shows that the discussed effect is clearly seen in these partial waves as the specific form of interference between resonance and background . another interesting application of this effect may be a pair of partial waves @xmath6 and @xmath7 where the picture is more complicated due to presence of several resonance states .
| 147
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1308.2711
|
la@xmath0sr@xmath1nio@xmath2 is well known to have a colossal dielectric constant ( @xmath3 ) . the la@xmath0sr@xmath1nio@xmath2 nanoparticle powder was prepared by a combinational method of solid state reaction and high - energy ball milling . magnetic measurements show that the material has a very small magnetic moment and paramagnetic characteristic at room temperature . the mixture of the nanoparticle powder ( 40@xmath4 vol . ) and paraffin ( 60@xmath4 vol . ) coated in the form of flat layers of different thicknesses ( @xmath5 ) exhibits strong microwave absorption resonances in the 4 - 18 ghz range . the reflection loss ( @xmath6 ) decreases with @xmath5 and reaches down to -36.7 db for @xmath7 mm . the impedance matching ( @xmath8 @xmath9 ) , rather than the phase matching mechanism , is found responsible for the resonance observed in the samples with @xmath10 mm . further increase of the thickness leads to @xmath11 at all frequencies and a reduced absorption . the influence of non - metal backing is also discussed . our observation suggests that la@xmath0sr@xmath1nio@xmath2 nanoparticles could be used as good fillers for high performance radar absorbing material . dielectrics ; electronic materials ; energy storage and conversion ; magnetic materials ; nanoparticles ; powder technology .
| 210
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0801.4168
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an overview is given about the capabilities provided by the jlab 12 gev upgrade to measure deeply virtual exclusive processes with high statistics and covering a large kinematics range in the parameters that are needed to allow reconstruction of a spatial image of the nucleon s quark structure . the measurements planned with clas12 will cross section asymmetries with polarized beams and with longitudinally and transversely polarized proton targets in the constrained kinematics @xmath0 . in addition , unpolarized dvcs cross sections , and doubly polarized beam target asymmetries will be measured as well . in this talk only the beam and target asymmetries will be discussed .
| 108
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astro-ph0503031
|
the recent detection of a young pulsar powering `` the mouse '' , g359.230.82 , as well as detailed imaging of surrounding nebular x - ray emission , have motivated us to investigate the structural details and polarization characteristics of the radio emission from this axisymmetric source with a supersonic bow shock . using polarization data at 3.6 and 6 cm , we find that the magnetic field wraps around the bow shock structure near the apex of the system , but downnstream runs parallel to the inferred direction of the pulsar s motion . the rotation measure ( rm ) distribution of the mouse also suggests that the low degree of polarization combined with a high rm ahead of the pulsar result from internal plasma within the bowshock region . in addition , using sub - arcsecond radio image of the mouse , we identify modulations in the brightness distribution of the mouse that may be associated with the unshocked pulsar wind behind the pulsar . lastly , we discuss the relationship between the mouse and its neighboring shell - type supernova remnant g359.10.5 and argue that these two sources could potentially have the same origin . ism : individual : ( g359.230.82 ) , pulsars : individual ( j17472958 ) , stars : neutron , stars : winds , outflows
| 222
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1112.3124
|
numerical utilities of the contact block reduction ( cbr ) method in evaluating the retarded green s function , are discussed for 3-d multi - band open systems that are represented by the atomic tight - binding ( tb ) and continuum @xmath0@xmath1@xmath2 ( kp ) band model . it is shown that the methodology to approximate solutions of open systems which has been already reported for the single - band effective mass model , can not be directly used for atomic tb systems , since the use of a set of zincblende crystal grids makes the inter - coupling matrix be non - invertible . we derive and test an alternative with which the cbr method can be still practical in solving tb systems . this @xmath3-@xmath4 @xmath5 method is validated by a proof of principles on small systems , and also shown to work excellent with the kp approach . further detailed analysis on the accuracy , speed , and scalability on high performance computing clusters , is performed with respect to the reference results obtained by the state - of - the - art recursive green s function and wavefunction algorithm . this work shows that the cbr method could be particularly useful in calculating resonant tunneling features , but show a limited practicality in simulating field effect transistors ( fets ) when the system is described with the atomic tb model . coupled to the kp model , however , the utility of the cbr method can be extended to simulations of nanowire fets .
| 259
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quant-ph0309021
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for a quantum system , a density matrix @xmath0 that is not pure can arise , via averaging , from a distribution @xmath1 of its wave function , a normalized vector belonging to its hilbert space @xmath2 . while @xmath0 itself does not determine a unique @xmath1 , additional facts , such as that the system has come to thermal equilibrium , might . it is thus not unreasonable to ask , which @xmath1 , if any , corresponds to a given thermodynamic ensemble ? to answer this question we construct , for any given density matrix @xmath0 , a natural measure on the unit sphere in @xmath2 , denoted @xmath3 . we do this using a suitable projection of the gaussian measure on @xmath2 with covariance @xmath0 . we establish some nice properties of @xmath3 and show that this measure arises naturally when considering macroscopic systems . in particular , we argue that it is the most appropriate choice for systems in thermal equilibrium , described by the canonical ensemble density matrix @xmath4 . @xmath3 may also be relevant to quantum chaos and to the stochastic evolution of open quantum systems , where distributions on @xmath2 are often used . key words : canonical ensemble in quantum theory ; probability measures on hilbert space ; gaussian measures ; density matrices .
| 222
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hep-ph0512006
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we study the radiative leptonic decays of heavy mesons within the covariant light - front model . using this model , both the form factors @xmath0 and @xmath1 have the same form when the heavy quark limit is taken . in addition , the relation between the form factor @xmath0 and the decay constant of heavy meson @xmath2 is obtained . the hadronic parameter @xmath3 can be determine by the parameters appearing in the wave function of heavy meson . we find that the value of @xmath3 is not only quite smaller than the one in the non - relativistic case , but also insensitive to the value of light quark mass @xmath4 . these results mean that the relativistic effects are very important in this work . we also obtain the branching ratio of @xmath5 is about @xmath6 , in agreement with the general estimates in the literature . 16 true pt 10 mm
| 155
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0705.1575
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the branching ratios and cp violations of the @xmath0 decays , including both the color - allowed and the color - suppressed modes , are investigated in detail within qcd framework by considering all diagrams which lead to three effective currents of two quarks . an intrinsic mass scale as a dynamical gluon mass is introduced to treat the infrared divergence caused by the soft collinear approximation in the endpoint regions , and the cutkosky rule is adopted to deal with a physical - region singularity of the on mass - shell quark propagators . when the dynamical gluon mass @xmath1 is regarded as a universal scale , it is extracted to be around @xmath2 mev from one of the well - measured @xmath0 decay modes . the resulting predictions for all branching ratios are in agreement with the current experimental measurements . as these decays have no penguin contributions , there are no direct @xmath3 asymmetries . due to interference between the cabibbo - suppressed and the cabibbo - favored amplitudes , mixing - induced @xmath3 violations are predicted in the @xmath4 decays to be consistent with the experimental data at 1-@xmath5 level . more precise measurements will be helpful to extract weak angle @xmath6 .
| 207
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0711.4298
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we calculate the propagator and the transition probabilities for a coherently driven three - state quantum system . the energies of the three states change linearly in time , whereas the interactions between them are pulse - shaped . we derive a highly accurate analytic approximation by assuming independent pairwise landau - zener transitions occurring instantly at the relevant avoided crossings , and adiabatic evolution elsewhere . quantum interferences are identified , which occur due to different possible evolution paths in hilbert space between an initial and a final state . a detailed comparison with numerical results for gaussian - shaped pulses demonstrates a remarkable accuracy of the analytic approximation . we use the analytic results to derive estimates for the half - width of the excitation profile , and for the parameters required for creation of a maximally coherent superposition of the three states . these results are of potential interest in ladder climbing in alkali atoms by chirped laser pulses , in quantum rotors , in transitions between zeeman sublevels of a @xmath0 level in a magnetic field , and in control of entanglement of a pair of spin-1/2 particles . the results for the three - state system can be generalized , without essential difficulties , to higher dimensions .
| 213
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astro-ph0602465
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we present detailed luminosity profiles of the young massive clusters m82-f , ngc 1569-a , and ngc 1705 - 1 which show significant departures from equilibrium ( king and eff ) profiles . we compare these profiles with those from @xmath0-body simulations of clusters which have undergone the rapid removal of a significant fraction of their mass due to gas expulsion . we show that the observations and simulations agree very well with each other suggesting that these young clusters are undergoing violent relaxation and are also losing a significant fraction of their _ stellar _ mass . that these clusters are not in equilibrium can explain the discrepant mass - to - light ratios observed in many young clusters with respect to simple stellar population models without resorting to non - standard initial stellar mass functions as claimed for m82-f and ngc 1705 - 1 . we also discuss the effect of rapid gas removal on the complete disruption of a large fraction of young massive clusters ( `` infant mortality '' ) . finally we note that even bound clusters may lose @xmath1 50% of their initial _ stellar _ mass due to rapid gas loss ( `` infant weight - loss '' ) . [ firstpage ] galaxies : star clusters stellar dynamics methods : @xmath0-body simulations
| 220
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cond-mat0508483
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we numerically study influence of a polychromatic perturbation on wave packet dynamics in one - dimensional double - well potential . it is found that time - dependence of the transition probability between the wells shows two kinds of the motion typically , coherent oscillation and irregular fluctuation combined to the delocalization of the wave packet , depending on the perturbation parameters . the coherent motion changes the irregular one as the strength and/or the number of frequency components of the perturbation increases . we discuss a relation between our model and decoherence in comparing with the result under stochastic perturbation . furthermore we compare the quantum fluctuation , tunneling in the quantum dynamics with ones in the semiquantal dynamics .
| 121
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astro-ph0508552
|
we present the decomposition of the stellar velocity ellipsoid using stellar velocity dispersions within a 40@xmath0 wedge about the major - axis ( @xmath1 ) , the epicycle approximation , and the asymmetric drift equation . thus , we employ no fitted forms for @xmath1 and escape interpolation errors resulting from comparisons of the major and minor axes . we apply the theoretical construction of the method to integral field data taken for ngc 3949 and ngc 3982 . we derive the vertical - to - radial velocity dispersion ratio ( @xmath2 ) and find ( 1 ) our decomposition method is accurate and reasonable , ( 2 ) ngc 3982 appears to be rather typical of an sb type galaxy with @xmath3 despite its high surface brightness and small size , and ( 3 ) ngc 3949 has a hot disk with @xmath4 .
| 145
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1701.05709
|
we extend a standard stochastic theory to study open quantum systems coupled to generic quantum environments including the three fundamental classes of non - interacting particles : bosons , fermions and spins . in this unified stochastic approach , the generalized stochastic liouville equation ( sle ) formally captures the exact quantum dissipations when noise variables with appropriate statistics for different bath models are applied . anharmonic effects of a non - gaussian bath are precisely encoded in the bath multi - time correlation functions that noise variables have to satisfy . staring from the sle , we devise a family of generalized hierarchical equations by averaging out the noise variables and expand bath multi - time correlation functions in a complete basis of orthonormal functions . the general hiearchical equations constitute systems of linear equations that provide numerically exact simulations of quantum dynamics . for bosonic bath models , our general hierarchical equation of motion reduces exactly to an extended version of hierarchical equation of motion which allows efficient simulation for arbitrary spectral densities and temperature regimes . similar efficiency and flexibility can be achieved for the fermionic bath models within our formalism . the spin bath models can be simulated with two complementary approaches in the presetn formalism . ( i ) they can be viewed as an example of non - gaussian bath models and be directly handled with the general hierarchical equation approach given their multi - time correlation functions . ( ii ) alterantively , each bath spin can be first mapped onto a pair of fermions and be treated as fermionic environments within the present formalism .
| 273
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0708.1123
|
we use molecular dynamics computer simulations to investigate a critical temperature @xmath0 for a dynamical glass transition as proposed by the mode - coupling theory ( mct ) of dense liquids in a glass forming ni@xmath1zr@xmath2-system . the critical temperature @xmath0 are analyzed from different quantities and checked the consistency of the estimated values , i.e. from ( i ) the non - vanishing nonergodicity parameters as asymptotic solutions of the mct equations in the arrested state , ( ii ) the @xmath3-parameters describing the approach of the melt towards the arrested state on the ergodic side , ( iii ) the diffusion coefficients in the melt . the resulting @xmath0 values are found to agree within about 10 @xmath4 .
| 121
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1609.01648
|
a spoof attack , a subset of presentation attacks , is the use of an artificial replica of a biometric in an attempt to circumvent a biometric sensor . liveness detection , or presentation attack detection , distinguishes between live and fake biometric traits and is based on the principle that additional information can be garnered above and beyond the data procured by a standard authentication system to determine if a biometric measure is authentic . the goals for the liveness detection ( livdet ) competitions are to compare software - based fingerprint liveness detection and artifact detection algorithms ( part 1 ) , as well as fingerprint systems which incorporate liveness detection or artifact detection capabilities ( part 2 ) , using a standardized testing protocol and large quantities of spoof and live tests . the competitions are open to all academic and industrial institutions which have a solution for either software - based or system - based fingerprint liveness detection . the livdet competitions have been hosted in 2009 , 2011 , 2013 and 2015 and have shown themselves to provide a crucial look at the current state of the art in liveness detection schemes . there has been a noticeable increase in the number of participants in livdet competitions as well as a noticeable decrease in error rates across competitions . participants have grown from four to the most recent thirteen submissions for fingerprint part 1 . fingerprints part 2 has held steady at two submissions each competition in 2011 and 2013 and only one for the 2015 edition . the continuous increase of competitors demonstrates a growing interest in the topic . fingerprint , liveness detection , biometric
| 282
|
1105.2209
|
the existence of doubly charged higgs bosons ( @xmath0 ) is a distinctive feature of the higgs triplet model ( htm ) , in which neutrinos obtain tree - level masses from the vacuum expectation value of a neutral scalar in a triplet representation of @xmath1 . we point out that a large branching ratio for the decay of a singly charged higgs boson to a doubly charged higgs boson via @xmath2 is possible in a sizeable parameter space of the htm . from the production mechanism @xmath3 the above decay mode would give rise to pair production of @xmath0 , with a cross section which can be comparable to that of the standard pair - production mechanism @xmath4 . we suggest that the presence of a sizeable branching ratio for @xmath2 could significantly enhance the detection prospects of @xmath0 in the four - lepton channel . moreover , the decays @xmath5 and @xmath6 from production of the neutral triplet scalars @xmath7 and @xmath8 would also provide an additional source of @xmath9 , which can subsequently decay to @xmath0 .
| 180
|
1305.4207
|
adiabatic processes are important for studying the dynamics of a time - dependent system . conventionally , the adiabatic processes can only be achieved by varying the system slowly . we speed up both classical and quantum adiabatic processes by adding control protocols . in classical systems , we work out the control protocols by analyzing the classical adiabatic approximation . in quantum systems , we follow the idea of transitionless driving by berry [ _ j . phys . a : math . theor . _ * 42 * 365303 ( 2009 ) ] . such fast - forward adiabatic processes can be performed at arbitrary fast speed , and in the meanwhile reduce the work fluctuation . in both systems , we use a time - dependent harmonic oscillator model to work out explicitly the work function and the work fluctuation in three types of processes : fast - forward adiabatic processes , adiabatic processes , and non - adiabatic processes . we show the significant reduction on work fluctuation in fast - forward adiabatic process . we further illustrate how the fast - forward process improved the converging rate of the jarzynski equality between the work function and the free energy . as an application , we show that the fast - forward process not only maximizes the output power but also improve the efficiency of a quantum engine .
| 233
|
1206.6664
|
dyadic data are common in the social and behavioral sciences , in which members of dyads are correlated due to the interdependence structure within dyads . the analysis of longitudinal dyadic data becomes complex when nonignorable dropouts occur . we propose a fully bayesian selection - model - based approach to analyze longitudinal dyadic data with nonignorable dropouts . we model repeated measures on subjects by a transition model and account for within - dyad correlations by random effects . in the model , we allow subject s outcome to depend on his / her own characteristics and measure history , as well as those of the other member in the dyad . we further account for the nonignorable missing data mechanism using a selection model in which the probability of dropout depends on the missing outcome . we propose a gibbs sampler algorithm to fit the model . simulation studies show that the proposed method effectively addresses the problem of nonignorable dropouts . we illustrate our methodology using a longitudinal breast cancer study . .
| 176
|
hep-ex0409057
|
the existence of an anti - decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model . in the last year , several experimental groups have reported evidence for a s=+1 baryon resonance , with mass ranging from 1.52 and 1.55 gev and width less than 25 mev , by looking at the invariant mass of the @xmath0 system . this resonance , has been identified with the lowest mass of the anti - decuplet , the @xmath1 . at the same time , there are a number of experiment , mostly at high energies , that report null results . + an overview of the experimental results so far obtained will be given here together with a review of the second generation experiments currently ongoing and planned at jefferson lab hall b.
| 138
|
quant-ph0410136
|
we present detailed numerical calculations of the mechanical torque induced by quantum fluctuations on two parallel birefringent plates with in plane optical anisotropy , separated by either vacuum or a liquid ( ethanol ) . the torque is found to vary as @xmath0 , where @xmath1 represents the angle between the two optical axes , and its magnitude rapidly increases with decreasing plate separation @xmath2 . for a 40 @xmath3 m diameter disk , made out of either quartz or calcite , kept parallel to a barium titanate plate at @xmath4 nm , the maximum torque ( at @xmath5 ) is of the order of @xmath6 n@xmath7 m . we propose an experiment to observe this torque when the barium titanate plate is immersed in ethanol and the other birefringent disk is placed on top of it . in this case the retarded van der waals ( or casimir - lifshitz ) force between the two birefringent slabs is repulsive . the disk would float parallel to the plate at a distance where its net weight is counterbalanced by the retarded van der waals repulsion , free to rotate in response to very small driving torques . pacs numbers : 12.20.-m,07.10.pz,46.55.+d
| 201
|
1612.03026
|
the paper describes a time - resolved photoemission ( trpes ) apparatus equipped with a yb - doped fiber laser system delivering 1.2-ev pump and 5.9-ev probe pulses at the repetition rate of 95 mhz . time and energy resolutions are 11.3 mev and @xmath0310 fs , respectively ; the latter is estimated by performing trpes on a highly oriented pyrolytic graphite ( hopg ) . the high repetition rate is suited for achieving high signal - to - noise ratio in trpes spectra , thereby facilitating investigations of ultrafast electronic dynamics in the low pump fluence ( @xmath1 ) region . trpes of polycrystalline bismuth ( bi ) at @xmath1 as low as 30 nj / mm@xmath2 is demonstrated . the laser source is compact and is docked to an existing trpes apparatus based on a 250-khz ti : sapphire laser system . the 95-mhz system is less prone to space - charge broadening effects compared to the 250-khz system , which we explicitly show in a systematic probe - power dependency of the fermi cutoff of polycrystalline gold . we also describe that the trpes response of an oriented bi(111)/hopg sample is useful for fine - tuning the spatial overlap of the pump and probe beams even when @xmath1 is as low as 30 nj / mm@xmath2 .
| 220
|
cond-mat0005495
|
we study how the multi - channel kondo effect is dynamically induced to affect the photoemission and the inverse photoemission spectrum when an electron is emitted from ( or added to ) the completely screened kondo impurity with spin @xmath0 . the spectrum thereby shows a power - law edge singularity characteristic of the multi - channel kondo model . we discuss this anomalous behavior by using the exact solution of the multi - channel kondo model and boundary conformal field theory . the idea is further applied to the photoemission for quantum spin systems , in which the edge singularity is controlled by the dynamically induced overscreening effect with a _ mobile _ kondo impurity .
| 117
|
1003.1883
|
we present a new approach of topology biased random walks for undirected networks . we focus on a one parameter family of biases and by using a formal analogy with perturbation theory in quantum mechanics we investigate the features of biased random walks . this analogy is extended through the use of parametric equations of motion ( pem ) to study the features of random walks _ vs. _ parameter values . furthermore , we show an analysis of the spectral gap maximum associated to the value of the second eigenvalue of the transition matrix related to the relaxation rate to the stationary state . applications of these studies allow _ ad hoc _ algorithms for the exploration of complex networks and their communities .
| 125
|
astro-ph0204386
|
the deuterium abundance evaluation in the direction of capella has for a long time been used as a reference for the local interstellar medium ( ism ) within our galaxy . we show here that broad and weak h@xmath0i components could be present on the capella line of sight , leading to a large new additional systematic uncertainty on the @xmath1(h@xmath0i ) evaluation . the d / h ratio toward capella is found to be equal to @xmath2 with almost identical @xmath3 for all the fits ( this range includes only the systematic error ; the 2 @xmath4 statistical one is almost negligible in comparison ) . it is concluded that d / h evaluations over h@xmath0i column densities below @xmath5 ( even perhaps below @xmath6 if demonstrated by additional observations ) may present larger uncertainties than previously anticipated . it is mentionned that the d / o ratio might be a better tracer for d@xmath0i variations in the ism as recently measured by the far ultraviolet spectroscopic explorer ( _ fuse _ ) .
| 175
|
1008.5000
|
a graph is called @xmath0-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge . in this paper , we establish a local property of @xmath0-planar graphs which describes the structure in the neighborhood of small vertices ( i.e. vertices of degree no more than seven ) . meanwhile , some new classes of light graphs in @xmath0-planar graphs with the bounded degree are found . therefore , two open problems presented by fabrici and madaras [ the structure of 1-planar graphs , discrete mathematics , 307 , ( 2007 ) , 854865 ] are solved . furthermore , we prove that each @xmath0-planar graph @xmath1 with maximum degree @xmath2 is acyclically edge @xmath3-choosable where @xmath4 . _ keywords _ : @xmath0-planar graph ; light graph ; acyclic edge coloring . please cite this published article as : _ x. zhang , g. liu , j .- l . wu . structural properties of 1-planar graphs and an application to acyclic edge coloring . scientia sinica mathematica , 2010 , 40 , 10251032_.
| 184
|
astro-ph0102011
|
we present results from a careful and detailed analysis of the structural and dynamical properties of a sample of 29 disc - like objects identified at @xmath0 in three ap3m - sph fully consistent cosmological simulations . these simulations are realizations of a cdm hierarchical model , where an _ inefficient _ schmidt law - like algorithm to model the stellar formation process has been implemented . we focus on properties that can be constrained with available data from observations of spiral galaxies , namely , the bulge and disc structural parameters and the rotation curves . comparison with data from broeils ( 1992 ) , de jong ( 1996 ) and courteau ( 1996 , 1997 ) gives satisfactory agreement , in contrast with previous findings using other codes . this suggests that the stellar formation implementation we have used has succeeded in forming compact bulges that stabilize disc - like structures in the violent phases of their assembly , while in the quiescent phases the gas has cooled and collapsed according with the fall & efstathiou standard model of disc formation . galaxies : evolution galaxies : formation galaxies : structure galaxies : spiral hydrodynamics methods : numerical cosmology : theory dark matter
| 205
|
1203.0894
|
it is demonstrated that measurements of positions of atoms scattered from a quasi - condensate in a raman process provide information on the temperature of the parent cloud . in particular , the widths of the density and second order correlation functions are sensitive to the phase fluctuations induced by non - zero temperature of the quasi - condensate . it is also shown how these widths evolve during expansion of the cloud of scattered atoms . these results are useful for planning future raman scattering experiments and indicate the degree of spatial resolution of atom - position measurements necessary to detect the temperature dependence of the quasi - condensate .
| 111
|
astro-ph0203189
|
recent x - ray observations have been used to demonstrate that the cluster gas mass - temperature relation is steeper than theoretical self - similar predictions drawn from numerical simulations that consider the evolution of the cluster gas through the effects of gravity and shock heating alone . one possible explanation for this is that the gas mass fraction is not constant across clusters of different temperature , as is usually assumed . observationally , however , there is no compelling evidence for gas mass fraction variation , especially in the case of hot clusters . seeking an alternative physical explanation for the observed trends , we investigate the role in the cluster gas mass - temperature relation of the preheating of the intracluster medium by some arbitrary source for clusters with emission - weighted mean temperatures of @xmath0 kev . making use of the physically - motivated , analytic models developed in 2002 by babul and coworkers , we find that preheating does , indeed , lead to a steeper relation . this is in agreement with previous theoretical studies on the relation . however , in apparent conflict with these studies , we argue that a `` high '' level of entropy injection is required to match observations . in particular , an entropy floor of @xmath1 kev @xmath2 is required . we also present a new test , namely , the study of the relation within different fixed radii . this allows one to indirectly probe the density profiles of clusters , since it samples different fractions of the virial radius for clusters of different temperature . this test also confirms that a high level of preheating is required to match observations .
| 286
|
astro-ph0703295
|
we present _ spitzer _ irac imaging of the large - scale jet in the quasar pks 1136@xmath0135 at wavelengths of 3.6 and @xmath1 , combined with previous _ vla _ , _ hst _ , and _ chandra _ observations . we clearly detect infrared emission from the jet , resulting in the most detailed multifrequency data among the jets in lobe - dominated quasars . the spectral energy distributions of the jet knots have significant variations along the jet , like the archetypal jet in 3c 273 . the infrared measurements with irac are consistent with the previous idea that the jet has two spectral components , namely ( 1 ) the low - energy synchrotron spectrum extending from radio to infrared , and ( 2 ) the high - energy component responsible for the x - ray flux . the optical fluxes may be a mixture of the two components . we consider three radiation models for the high - energy component : inverse compton scattering of cosmic microwave background ( cmb ) photons by radio - emitting electrons in a highly relativistic jet , synchrotron radiation by a second distinct electron population , and synchrotron radiation by ultra high energy protons . each hypothesis leads to important insights into and constraints on particle acceleration in the jet , as well as the basic physical properties of the jet such as bulk velocity , transporting power , and particle contents .
| 244
|
1005.0260
|
ccd photometric observations in @xmath0 colors and spectroscopic observations of the newly discovered eclipsing binary gsc 2314 - 0530 ( nsvs 6550671 ) with dme components and very short period of @xmath1 days are presented . the simultaneous light - curve solution and radial velocity solution allows to determine the global parameters of gsc 2314 - 0530 : @xmath2 k ; @xmath3 k ; @xmath4 m@xmath5 ; @xmath6 m@xmath5 ; @xmath7 r@xmath5 ; @xmath8 r@xmath5 ; @xmath9 l@xmath5 ; @xmath10 l@xmath5 ; @xmath11 ; @xmath12 r@xmath5 ; @xmath13 pc . the chromospheric activity of its components is revealed by strong emission in the h@xmath14 line ( with mean @xmath15 ) and observed several flares . empirical relations mass@xmath16 , mass radius and mass temperature are derived on the basis of the parameters of known binaries with low - mass dm components . [ firstpage ] binaries : eclipsing binaries : spectroscopic stars : activity stars : fundamental parameters stars : late - type stars : low - mass
| 168
|
0810.3400
|
a unified scheme for quantum measurement processes is formulated on the basis of micro - macro duality as a mathematical expression of the general idea of _ quantum - classical correspondence_. in this formulation , we can naturally accommodate the amplification processes necessary for magnifying quantum state changes at the microscopic end of the probe system into the macroscopically visible motion of the measuring pointer . its essence is exemplified and examined in the concrete model of the stern - gerlach experiment for spin measurement , where the helgason duality controlling the radon transform is seen to play essential roles .
| 101
|
1108.1350
|
active peer - to - peer ( p2p ) worms present serious threats to the global internet by exploiting popular p2p applications to perform rapid topological self - propagation . active p2p worms pose more deadly threats than normal scanning worms because they do not exhibit easily detectable anomalies , thus many existing defenses are no longer effective . we propose an immunity system with _ phagocytes _ a small subset of elected p2p hosts that are immune with high probability and specialized in finding and `` eating '' worms in the p2p overlay . the phagocytes will monitor their managed p2p hosts connection patterns and traffic volume in an attempt to detect active p2p worm attacks . once detected , local isolation , alert propagation and software patching will take place for containment . the phagocytes further provide the access control and filtering mechanisms for communication establishment between the internal p2p overlay and the external hosts . we design a novel adaptive and interaction - based computational puzzle scheme at the phagocytes to restrain external worms attacking the p2p overlay , without influencing legitimate hosts experiences significantly . we implement a prototype system , and evaluate its performance based on realistic massive - scale p2p network traces . the evaluation results illustrate that our phagocytes are capable of achieving a total defense against active p2p worms .
| 228
|
1510.02016
|
we investigate equatorial geodesics in the gravitational field of a rotating and deformed source described by the approximate hartle - thorne metric . in the case of massive particles , we derive within the same approximation analytic expressions for the orbital angular velocity , the specific angular momentum and energy , and the radii of marginally stable and marginally bound circular orbits . moreover , we calculate the orbital angular velocity and the radius of lightlike circular geodesics . we study numerically the frame dragging effect and the influence of the quadrupolar deformation of the source on the motion of test particles . we show that the effects originating from the rotation can be balanced by the effects due to the oblateness of the source .
| 126
|
1312.7297
|
we develop a new method to measure source proper motions in microlensing events , which can partially overcome problems due to blending . it takes advantage of the fact that the source position is known precisely from the microlensing event itself . we apply this method to the event moa-2011-blg-262 , which has a short timescale @xmath0day , a companion mass ratio @xmath1 and a very high or high lens - source relative proper motion @xmath2 or @xmath3 ( for two possible models ) . these three characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly earth - mass `` moon '' . the probability of such an interpretation would be greatly increased if it could be shown that the high lens - source relative proper motion was primarily due to the lens rather than the source . based on the long - term monitoring data of the galactic bulge from the optical gravitational lensing experiment ( ogle ) , we measure the source proper motion that is small , @xmath4 in a ( north , east ) galactic coordinate frame . these values are then important input into a bayesian analysis of the event presented in a companion paper by bennett et al .
| 213
|
cond-mat0607527
|
a general framework for performing event - driven simulations of systems with semi - flexible or rigid bodies interacting under impulsive torques and forces is outlined . two different approaches are presented . in the first , the dynamics and interaction rules are derived from lagrangian mechanics in the presence of constraints . this approach is most suitable when the body is composed of relatively few point masses or is semi - flexible . in the second method , the equations of rigid bodies are used to derive explicit analytical expressions for the free evolution of arbitrary rigid molecules and to construct a simple scheme for computing interaction rules . efficient algorithms for the search for the times of interaction events are designed in this context , and the handling of missed interaction events is discussed .
| 137
|
1112.4344
|
we introduce a scalable algorithm , mucca for multiclass node classification in weighted graphs . unlike previously proposed methods for the same task , mucca works in time linear in the number of nodes . our approach is based on a game - theoretic formulation of the problem in which the test labels are expressed as a nash equilibrium of a certain game . however , in order to achieve scalability , we find the equilibrium on a spanning tree of the original graph . experiments on real - world data reveal that mucca is much faster than its competitors while achieving a similar predictive performance .
| 107
|
1312.7733
|
we derive a general expression for the electron nonequilibrium ( ne ) distribution function in the context of steady state quantum transport through a two - terminal nanodevice with interaction . the central idea for the use of ne distributions for open quantum systems is that both the ne and many - body ( mb ) effects are taken into account in the statistics of the finite size system connected to reservoirs . we develop an alternative scheme to calculate the ne steady state properties of such systems . the method , using ne distribution and spectral functions , presents several advantages , and is equivalent to conventional steady - state ne green s functions ( negf ) calculations when the same level of approximation for the mb interaction is used . the advantages of our method resides in the fact that the ne distribution and spectral functions have better analytic behaviour for numerical calculations . furthermore our approach offer the possibility of introducing further approximations , not only at the level of the mb interaction as in negf , but also at the level of the functional form used for the ne distributions . for the single level model with electron - phonon coupling we have considered , such approximations provide a good representation of the exact results , for either the ne distributions themselves or the transport properties . we also derive the formal extensions of our method for systems consisting of several electronic levels and several vibration modes .
| 252
|
nucl-th0106015
|
the spectral function of @xmath0he is extracted from a plane - wave approximation to the @xmath1 reaction using a fully relativistic formalism . we take advantage of both an algebraic `` trick '' and a general relativistic formalism for quasifree processes developed earlier to arrive at transparent , analytical expressions for all quasifree @xmath1 observables . an observable is identified for the clean and model - independent extraction of the spectral function . our simple relativistic plane - wave calculations provide baseline predictions for the recently measured , but not yet fully analyzed , momentum distribution of @xmath0he by the @xmath2-collaboration from mainz . yet in spite of its simplicity , our approach predicts momentum distributions for @xmath0he that rival some of the best nonrelativistic calculations to date . finally , we highlight some of the challenges and opportunities that remain , both theoretically and experimentally , in the extraction of quasifree observables .
| 154
|
astro-ph0701116
|
near - infrared and optical imaging of hd32297 indicate that it has an edge - on debris disk , similar to @xmath0 pic . i present high resolution optical spectra of the doublet toward hd32297 and stars in close angular proximity . a circumstellar absorption component is clearly observed toward hd32297 at the stellar radial velocity , which is not observed toward any of its neighbors , including the nearest only 0@xmath19 away . an interstellar component is detected in all stars @xmath290pc , including hd32297 , likely due to the interstellar material at the boundary of the local bubble . radial velocity measurements of the nearest neighbors , bd+07777s and bd+07778 , indicate that they are unlikely to be physically associated with hd32297 . the measured circumstellar column density around hd32997 , @xmath3 , is the strongest absorption measured toward any nearby main sequence debris disk , even the prototypical edge - on debris disk , @xmath0 pic . assuming that the morphology and abundances of the gas component around hd32297 are similar to @xmath0 pic , i estimate an upper limit to the gas mass in the circumstellar disk surrounding hd32297 of @xmath40.3 @xmath5 .
| 197
|
1310.4222
|
the spin seebeck effect is studied across a charge insulating magnetic junction , in which thermal - spin conjugate transport is assisted by the exchange interactions between the localized spin in the center and electrons in metallic leads . we show that , in contrast with bulk spin seebeck effect , the figure of merit of such nanoscale thermal - spin conversion can be infinite , leading to the ideal carnot efficiency in the linear response regime . we also find that in the nonlinear spin seebeck transport regime , the device possesses the asymmetric and negative differential spin seebeck effects . in the last , the situations with leaking electron tunneling are also discussed . this nanoscale thermal spin rectifier , by tuning the junction parameters , can act as a spin seebeck diode , spin seebeck transistor and spin seebeck switch , which could have substantial implications for flexible thermal and information control in molecular spin caloritronics .
| 160
|
1012.1165
|
we show that the newly measured branching ratios of vector charmonia ( @xmath0 , @xmath1 and @xmath2 into @xmath3 , where @xmath4 stands for light pseudoscalar mesons @xmath5 , @xmath6 , and @xmath7 , can be well understood in the framework of vector meson dominance ( vmd ) in association with the @xmath8-@xmath9 mixings due to the axial gluonic anomaly . these two mechanisms behave differently in @xmath0 and @xmath10 . a coherent understanding of the branching ratio patterns observed in @xmath11 can be achieved by self - consistently including those transition mechanisms at hadronic level . the branching ratios for @xmath12 are predicted to be rather small .
| 109
|
cond-mat0202129
|
phase transitions can occur in one - dimensional classical statistical mechanics at non - zero temperature when the number of components @xmath0 of the spin is infinite . we show how to solve such magnets in one dimension for any @xmath0 , and how the phase transition develops at @xmath1 . we discuss @xmath2 and @xmath3 magnets , where the transition is second - order . in the new high - temperature phase , the correlation length is zero . we also show that for the @xmath2 magnet on exactly three sites with periodic boundary conditions , the transition becomes first order .
| 103
|
0710.5488
|
we present _ spitzer _ images of the relatively sparse , low luminosity young cluster l988e , as well as complementary near - infrared ( nir ) and submillimeter images of the region . the cluster is asymmetric , with the western region of the cluster embedded within the molecular cloud , and the slightly less dense eastern region to the east of , and on the edge of , the molecular cloud . with these data , as well as with extant h@xmath0 data of stars primarily found in the eastern region of the cluster , and a molecular @xmath1co gas emission map of the entire region , we investigate the distribution of forming young stars with respect to the cloud material , concentrating particularly on the differences and similarities between the exposed and embedded regions of the cluster . we also compare star formation in this region to that in denser , more luminous and more massive clusters already investigated in our comprehensive multi - wavelength study of young clusters within 1 kpc of the sun .
| 179
|
0806.4576
|
we analyse an epidemiological model of competing strains of pathogens and hence differences in transmission for first versus secondary infection due to interaction of the strains with previously aquired immunities , as has been described for dengue fever ( in dengue known as antibody dependent enhancement , ade ) . such models show a rich variety of dynamics through bifurcations up to deterministic chaos . including temporary cross - immunity even enlarges the parameter range of such chaotic attractors , and also gives rise to various coexisting attractors , which are difficult to identify by standard numerical bifurcation programs using continuation methods . a combination of techniques , including classical bifurcation plots and lyapunov exponent spectra has to be applied in comparison to get further insight into such dynamical structures . here we present for the first time multi - parameter studies in a range of biologically plausible values for dengue . the multi - strain interaction with the immune system is expected to also have implications for the epidemiology of other diseases . numerical bifurcation analysis , lyapunov exponents , @xmath0 symmetry , coexisting attractors , antibody dependent enhancement ( ade ) regino criado , j. vigo aguiar maira@igc.gulbenkian.pt1 nico@ptmat.fc.ul.pt1 kooi@falw.vu.nl2
| 202
|
1502.01138
|
in order to clarify thermodynamic stability of mg - based long - period stacking ordered ( lpso ) structure , we systematically study energetic preference for alloys on multiple stacking with different composition for random mixing of constituent elements , mg , y , and zn based on special quasirandom structure ( sqs ) . through calculation of formation free energy of sqs , mg - y - zn alloy exhibits phase separation into mg- and y - zn rich phase , which is consistent with previous theoretical studies . bulk modulus of sqss for multiple compositions , stacking sequences , and atomic configurations ranges around 35 gpa , @xmath0 , they do not show significant dependence of mg concentration , which therefore means that the effects of phonon do not play significant role on lpso phase stability . introducing stacking fault to hcp stacking gains `` negative '' energy , which indicates profound relationship between introducing stacking faults and the formation of long - period stacking ordering .
| 169
|
hep-ph0606084
|
in the limit of heavy quark masses going to infinity , a symmetry is known to emerge in qcd relating properties of hadrons with two heavy quarks to analogous states with one heavy anti - quark . a key question is whether the charm mass is heavy enough so that this symmetry is manifest in at least an approximate manner . the issue is crucial in attempting to understand the recent reports by the selex collaboration of doubly charmed baryons . we argue on very general grounds that the charm quark mass is substantially too light for the symmetry to emerge automatically via colour coulombic interactions . however , the symmetry could emerge approximately depending on the dynamical details of the non - perturbative physics . to treat the problem systematically , a new expansion that simultaneously incorporates nrqcd and hqet is needed .
| 144
|
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