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1405.3379
|
additive models play an important role in semiparametric statistics . this paper gives learning rates for regularized kernel based methods for additive models . these learning rates compare favourably in particular in high dimensions to recent results on optimal learning rates for purely nonparametric regularized kernel based quantile regression using the gaussian radial basis function kernel , provided the assumption of an additive model is valid . additionally , a concrete example is presented to show that a gaussian function depending only on one variable lies in a reproducing kernel hilbert space generated by an additive gaussian kernel , but does not belong to the reproducing kernel hilbert space generated by the multivariate gaussian kernel of the same variance . * key words and phrases . * additive model , kernel , quantile regression , semiparametric , rate of convergence , support vector machine .
| 145
|
nlin0608019
|
in 84 , 258 ( 2000 ) , mateos conjectured that current reversal in a classical deterministic ratchet is associated with bifurcations from chaotic to periodic regimes . this is based on the comparison of the current and the bifurcation diagram as a function of a given parameter for a periodic asymmetric potential . barbi and salerno , in 62 , 1988 ( 2000 ) , have further investigated this claim and argue that , contrary to mateos claim , current reversals can occur also in the absence of bifurcations . barbi and salerno s studies are based on the dynamics of one particle rather than the statistical mechanics of an ensemble of particles moving in the chaotic system . the behavior of ensembles can be quite different , depending upon their characteristics , which leaves their results open to question . in this paper we present results from studies showing how the current depends on the details of the ensemble used to generate it , as well as conditions for convergent behavior ( that is , independent of the details of the ensemble ) . we are then able to present the converged current as a function of parameters , in the same system as mateos as well as barbi and salerno . we show evidence for current reversal without bifurcation , as well as bifurcation without current reversal . we conjecture that it is appropriate to correlate abrupt changes in the current with bifurcation , rather than current reversals , and show numerical evidence for our claims .
| 260
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hep-ph0605279
|
with a special intention of clarifying the underlying spin contents of the nucleon , we investigate the generalized form factors of the nucleon , which are defined as the @xmath0-th @xmath1-moments of the generalized parton distribution functions , within the framework of the chiral quark soliton model . a particular emphasis is put on the pion mass dependence of final predictions , which we shall compare with the predictions of lattice qcd simulations carried out in the so - called heavy pion region around @xmath2 . we find that some observables are very sensitive to the variation of the pion mass . it will be argued that the negligible importance of the quark orbital angular momentum indicated by the lhpc and qcdsf lattice collaborations might be true in the unrealistic heavy pion world , but it is not necessarily the case in our real world close to the chiral limit .
| 151
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1511.00051
|
synaptic memory is considered to be the main element responsible for learning and cognition in humans . although traditionally non - volatile long - term plasticity changes have been implemented in nanoelectronic synapses for neuromorphic applications , recent studies in neuroscience have revealed that biological synapses undergo meta - stable volatile strengthening followed by a long - term strengthening provided that the frequency of the input stimulus is sufficiently high . such `` memory strengthening '' and `` memory decay '' functionalities can potentially lead to adaptive neuromorphic architectures . in this paper , we demonstrate the close resemblance of the magnetization dynamics of a magnetic tunnel junction ( mtj ) to short - term plasticity and long - term potentiation observed in biological synapses . we illustrate that , in addition to the magnitude and duration of the input stimulus , frequency of the stimulus plays a critical role in determining long - term potentiation of the mtj . such mtj synaptic memory arrays can be utilized to create compact , ultra - fast and low power intelligent neural systems .
| 182
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0706.1962
|
long time coverage and high radial velocity precision have allowed for the discovery of additional objects in known planetary systems . many of the extrasolar planets detected have highly eccentric orbits , which raises the question of how likely those systems are to host additional planets . we investigate six systems which contain a very eccentric ( @xmath0 ) planet : hd 3651 , hd 37605 , hd 45350 , hd 80606 , hd 89744 , and 16 cyg b. we present updated radial - velocity observations and orbital solutions , search for additional planets , and perform test particle simulations to find regions of dynamical stability . the dynamical simulations show that short - period planets could exist in the hd 45350 and 16 cyg b systems , and we use the observational data to set tight detection limits , which rule out additional planets down to a few neptune masses in the hd 3651 , hd 45350 , and 16 cyg b systems .
| 166
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1008.0881
|
we study equilibrium configurations of swarming biological organisms subject to exogenous and pairwise endogenous forces . beginning with a discrete dynamical model , we derive a variational description of the corresponding continuum population density . equilibrium solutions are extrema of an energy functional , and satisfy a fredholm integral equation . we find conditions for the extrema to be local minimizers , global minimizers , and minimizers with respect to infinitesimal lagrangian displacements of mass . in one spatial dimension , for a variety of exogenous forces , endogenous forces , and domain configurations , we find exact analytical expressions for the equilibria . these agree closely with numerical simulations of the underlying discrete model.the exact solutions provide a sampling of the wide variety of equilibrium configurations possible within our general swarm modeling framework . the equilibria typically are compactly supported and may contain @xmath0-concentrations or jump discontinuities at the edge of the support . we apply our methods to a model of locust swarms , which are observed in nature to consist of a concentrated population on the ground separated from an airborne group . our model can reproduce this configuration ; quasi - two - dimensionality of the model plays a critical role . swarm , equilibrium , aggregation , integrodifferential equation , variational model , energy , minimizer , locust
| 223
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hep-ph0605134
|
i discuss new results on absolute branching ratios of charm mesons into specific exclusive final states , cabibbo suppressed decay rates , inclusive decays to @xmath0 mesons , limits on @xmath1 mixing , cp violation and t violation . preliminary results from cleo - c now dominate the world average absolute branching fractions . for the most important normalization modes involving @xmath2 and @xmath3 , the averages are @xmath4 for the @xmath5 cleo - c measures @xmath6 . using this rate , i derive an effective branching ratio @xmath7 , that is appropriate for use in extracting other branching fractions that have often been measured relative to this mode . this number is compared with other determinations .
| 118
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cond-mat0506313
|
we present a two - channel model to describe the quantum state of two atoms with finite - range interaction near a feshbach resonance . this model provides a simple picture to analytically derive the wave function and the binding energy of the molecular bound state . the results agree excellently with the measurements and multichannel calculations . for small binding energies , the system enters a threshold regime in which the feshbach molecules are identical to long range atom pairs in single channel . according to their threshold behavior , we find feshbach resonances can be classified into two types .
| 102
|
cond-mat9907309
|
we calculate cross sections for low energy elastic exciton - exciton scattering within the effective mass approximation . unlike previous theoretical approaches , we give a complete , non - perturbative treatment of the four - particle scattering problem . diffusion monte carlo is used to calculate the essentially exact energies of scattering states , from which phase shifts are determined . for the case of equal - mass electrons and holes , which is equivalent to positronium - positronium scattering , we find @xmath0 for scattering of singlet - excitons and @xmath1 for triplet - excitons , where @xmath2 is the excitonic radius . the spin dependence of the cross sections arises from the spatial exchange symmetry of the scattering wavefunctions . a significant triplet - triplet to singlet - singlet scattering process is found , which is similar to reported effects in recent experiments and theory for excitons in quantum wells . we also show that the scattering length can change sign and diverge for some values of the mass ratio @xmath3/@xmath4 , an effect not seen in previous perturbative treatments .
| 184
|
0909.2256
|
we present a novel method for calculating the primordial non - gaussianity produced by super - horizon evolution during inflation . our method evolves the distribution of coarse - grained inflationary field values using a transport equation . we present simple evolution equations for the moments of this distribution , such as the variance and skewness . this method possesses some advantages over existing techniques . among them , it cleanly separates multiple sources of primordial non - gaussianity , and is computationally efficient when compared with popular alternatives , such as the @xmath0 framework . we adduce numerical calculations demonstrating that our new method offers good agreement with those already in the literature . we focus on two fields and the @xmath1 parameter , but we expect our method will generalize to multiple scalar fields and to moments of arbitrarily high order . we present our expressions in a field - space covariant form which we postulate to be valid for any number of fields . * keywords * : inflation , cosmological perturbation theory , physics of the early universe , quantum field theory in curved spacetime .
| 190
|
1508.06930
|
for @xmath0 and @xmath1 , we consider certain admissible sequences of @xmath2 lattice paths in a colored @xmath3 square . we show that the number of such admissible sequences of lattice paths is given by the sum of squares of the number of standard young tableaux of partitions of @xmath4 with height @xmath5 , which is also the number of @xmath6-avoiding permutations of @xmath7 . finally , we apply this result to the representation theory of the affine lie algebra @xmath8 and show that this quantity gives the multiplicity of certain maximal dominant weights in the irreducible module @xmath9 .
| 100
|
1007.1918
|
various new physics models predict a light cp - odd higgs boson ( labeled as @xmath0 ) and open up new decay modes for @xmath1-boson , such as @xmath2 , @xmath3 and @xmath4 , which could be explored at the gigaz option of the ilc . in this work we investigate these rare decays in several new physics models , namely the type - ii two higgs doublet model ( type - ii 2hdm ) , the lepton - specific two higgs doublet model ( l2hdm ) , the nearly minimal supersymetric standard model ( nmssm ) and the next - to - minimal supersymmetric standard model ( nmssm ) . we find that in the parameter space allowed by current experiments , the branching ratios can reach @xmath5 for @xmath6 ( @xmath7 ) , @xmath8 for @xmath3 and @xmath9 for @xmath4 , which implies that the decays @xmath10 and @xmath11 may be accessible at the gigaz option . moreover , since different models predict different patterns of the branching ratios , the measurement of these rare decays at the gigaz may be utilized to distinguish the models .
| 189
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astro-ph0310704
|
dwarf galaxies in the local group provide a unique astrophysical laboratory . despite their proximity some of these systems still lack a reliable distance determination as well as studies of their stellar content and star formation history . we present first results of our survey of variable stars in a sample of six local group dwarf irregular galaxies . taking the leo a dwarf galaxy as an example we describe observational strategies and data reduction . we discuss the lightcurves of two newly found @xmath0 cephei stars and place them into the context of a previously derived p - l relation . finally we discuss the lpv content of leo a.
| 111
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1501.01494
|
the generation of hydrodynamic radiation in interactions of pulsed proton and laser beams with matter is explored . the beams were directed into a water target and the resulting acoustic signals were recorded with pressure sensitive sensors . measurements were performed with varying pulse energies , sensor positions , beam diameters and temperatures . the obtained data are matched by simulation results based on the thermo - acoustic model with uncertainties at a level of 10@xmath0 . the results imply that the primary mechanism for sound generation by the energy deposition of particles propagating in water is the local heating of the medium . the heating results in a fast expansion or contraction and a pressure pulse of bipolar shape is emitted into the surrounding medium . an interesting , widely discussed application of this effect could be the detection of ultra - high energetic cosmic neutrinos in future large - scale acoustic neutrino detectors . for this application a validation of the sound generation mechanism to high accuracy , as achieved with the experiments discussed in this article , is of high importance . cosmic neutrinos , acoustic neutrino detection , thermo - acoustic model , ultra - high energy cosmic rays , beam interaction
| 206
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1606.05955
|
the wide field camera 3 ( wfc3 ) on the _ hubble space telescope _ ( _ hst _ ) enabled the search for the first galaxies observed at @xmath0 ( @xmath1 myr after the big bang ) . to continue quantifying the number density of the most luminous galaxies ( @xmath2 ) at the earliest epoch observable with _ hst _ , we search for @xmath3 galaxies ( f125w - dropouts ) in archival data from the brightest of reionizing galaxies ( borg[z8 ] ) survey , originally designed for detection of @xmath4 galaxies ( f098m - dropouts ) . by focusing on the deepest 293 arcmin@xmath5 of the data along 62 independent lines of sight , we identify six @xmath3 candidates satisfying the color selection criteria , detected at s / n @xmath6 in f160w with @xmath7 to @xmath8 if at @xmath9 . three of the six sources , including the two brightest , are in a single wfc3 pointing ( @xmath10 arcmin@xmath5 ) , suggestive of significant clustering , which is expected from bright galaxies at @xmath11 . however , the two brightest galaxies are too extended to be likely at @xmath11 , and one additional source is unresolved and possibly a brown dwarf . the remaining three candidates have @xmath12 , and given the area and completeness of our search , our best estimate is a number density of sources that is marginally higher but consistent at @xmath13 with searches in legacy fields . our study highlights that @xmath11 searches can yield a small number of candidates , making tailored follow - ups of _ hst _ pure - parallel observations viable and effective .
| 279
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0905.2691
|
we investigate the emergence of magnetic flux in the quiet sun at very small spatial scales , focusing on the magnetic connection between the photosphere and chromosphere . the observational data consist of spectropolarimetric measurements and filtergrams taken with the hinode satellite and the dutch open telescope . we find that a significant fraction of the magnetic flux present in internetwork regions appears in the form of @xmath0-shaped loops . the emergence rate is 0.02 loops per hour and arcsec@xmath1 , which brings @xmath2 mx s@xmath3 arcsec@xmath1 of new flux to the solar surface . initially , the loops are observed as small patches of linear polarization above a granular cell . shortly afterwards , two footpoints of opposite polarity become visible in circular polarization within or at the edges of the granule and start to move toward the adjacent intergranular space . the orientation of the footpoints does not seem to obey hale s polarity rules . the loops are continuously buffeted by convective motions , but they always retain a high degree of coherence . interestingly , 23% of the loops that emerge in the photosphere reach the chromosphere ( 16 cases out of 69 ) . they are first detected in 630 nm magnetograms and 5 minutes later in b 517.3 nm magnetograms . after about 8 minutes , some of them are also observed in h line - core images , where the footpoints produce small brightness enhancements .
| 243
|
0903.4724
|
we apply the statefinder diagnostic to the torsion cosmology , in which an accounting for the accelerated universe is considered in term of a riemann - cartan geometry : dynamic scalar torsion . we find that there are some typical characteristic of the evolution of statefinder parameters for the torsion cosmology that can be distinguished from the other cosmological models . furthermore , we also show that statefinder diagnostic has a direct bearing on the critical points . the statefinder diagnostic divides the torsion parameter @xmath0 into differential ranges , which is in keeping with the requirement of dynamical analysis . in addition , we fit the scalar torsion model to essence supernovae data and give the best fit values of the model parameters .
| 125
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1211.7095
|
matched - filtering for the identification of compact object mergers in gravitational - wave antenna data involves the comparison of the data stream to a bank of template gravitational waveforms . typically the template bank is constructed from phenomenological waveform models since these can be evaluated for an arbitrary choice of physical parameters . recently it has been proposed that singular value decomposition ( svd ) can be used to reduce the number of templates required for detection . as we show here , another benefit of svd is its removal of biases from the phenomenological templates along with a corresponding improvement in their ability to represent waveform signals obtained from numerical relativity ( nr ) simulations . using these ideas , we present a method that calibrates a reduced svd basis of phenomenological waveforms against nr waveforms in order to construct a new waveform approximant with improved accuracy and faithfulness compared to the original phenomenological model . the new waveform family is given numerically through the interpolation of the projection coefficients of nr waveforms expanded onto the reduced basis and provides a generalized scheme for enhancing phenomenological models .
| 190
|
1104.4750
|
we investigate an efficient quantum error correction of a fully correlated noise . suppose the noise is characterized by a quantum channel whose error operators take fully correlated forms given by @xmath0 , @xmath1 and @xmath2 , where @xmath3 is the number of qubits encoding the codeword . it is proved that ( i ) @xmath4 qubits codeword encodes @xmath5 data qubits when @xmath4 is odd and ( ii ) @xmath4 qubits codeword implements an error - free encoding , which encode @xmath6 data qubits when @xmath4 is even . quantum circuits implementing these schemes are constructed . quantum error correction , higher rank numerical range , recovery operator , mixed unitary channel
| 113
|
0908.1913
|
this is the first attempt to model the kinematics of a cme launch and the resulting euv dimming quantitatively with a self - consistent model . our 4d - model assumes self - similar expansion of a spherical cme geometry that consists of a cme front with density compression and a cavity with density rarefaction , satisfying mass conservation of the total cme and swept - up corona . the model contains 14 free parameters and is fitted to the 2008 march 25 cme event observed with stereo / a and b. our model is able to reproduce the observed cme expansion and related euv dimming during the initial phase from 18:30 ut to 19:00 ut . the cme kinematics can be characterized by a constant acceleration ( i.e. , a constant magnetic driving force ) . while the observations of euvi / a are consistent with a spherical bubble geometry , we detect significant asymmetries and density inhomogeneities with euvi / b . this new forward - modeling method demonstrates how the observed euv dimming can be used to model physical parameters of the cme source region , the cme geometry , and cme kinematics .
| 197
|
1108.0797
|
we construct a simply connected minimal complex surface of general type with @xmath0 and @xmath1 which has an involution such that the minimal resolution of the quotient by the involution is a simply connected minimal complex surface of general type with @xmath0 and @xmath2 . in order to construct the example , we combine a double covering and @xmath3-gorenstein deformation . especially , we develop a method for proving unobstructedness for deformations of a singular surface by generalizing a result of burns and wahl which characterizes the space of first order deformations of a singular surface with only rational double points . we describe the stable model in the sense of kollr and shepherd - barron of the singular surfaces used for constructing the example . we count the dimension of the invariant part of the deformation space of the example under the induced @xmath4-action .
| 146
|
hep-ph0102030
|
no - scale structure of the khler potential is obtained in many types of supersymmetric models . in this paper , phenomenological aspects of these models are investigated with special attention to the current higgs mass bound at lep and @xmath0 result at the cleo . when the boundary condition is given at the gut scale and gaugino masses are universal at this scale , very narrow parameter region is allowed only for positive higgsino mass region if r - parity is conserved . the negative higgsino mass case is entirely excluded . on the other hand , relatively large parameter region is allowed when the boundary condition is given above the gut scale , and tevatron can discover susy signals for the positive higgsino mass case . the no - scale models with wino , higgsino or sneutrino lsp are also considered . we show that the higgs mass constraint is important for the higgsino lsp case , which requires the lsp mass to be larger than about 245 gev . 0.0 mm 0.0 mm 159.2 mm -16.0 mm 240.0 mm
| 182
|
1305.7010
|
the estimation of the number of passengers with the identical journey is a common problem for public transport authorities . this problem is also known as the origin - destination estimation ( od ) problem and it has been widely studied for the past thirty years . however , the theory is missing when the observations are not limited to the passenger counts but also includes station surveys . + our aim is to provide a solid framework for the estimation of an od matrix when only a portion of the journey counts are observable . + our method consists of a statistical estimation technique for od matrix when we have the sum - of - row counts and survey - based observations . our technique differs from the previous studies in that it does not need a prior od matrix which can be hard to obtain . instead , we model the passengers behaviour through the survey data , and use the diagonalization of the partial od matrix to reduce the space parameter and derive a consistent global od matrix estimator . we demonstrate the robustness of our estimator and apply it to several examples showcasing the proposed models and approach . we highlight how other sources of data can be incorporated in the model such as explanatory variables , e.g. rainfall , indicator variables for major events , etc , and inference made in a principled , non - heuristic way . constraint maximum likelihood estimation , eigenvectors , counts estimation
| 253
|
quant-ph0605207
|
we propose and experimentally demonstrate a method for non - invasive measurements of cavity parameters by injection of squeezed vacuum into an optical cavity . the principle behind this technique is the destruction of the correlation between upper and lower quantum sidebands with respect to the carrier frequency when the squeezed field is incident on the cavity . this method is especially useful for ultrahigh @xmath0 cavities , such as whispering gallery mode ( wgm ) cavities , in which absorption and scattering by light - induced nonlinear processes inhibit precise measurements of the cavity parameters . we show that the linewidth of a test cavity is measured to be @xmath1 khz , which agrees with the classically measured linewidth of the cavity within the uncertainty ( @xmath2 khz ) .
| 131
|
1105.2710
|
to investigate chemical reactivity of cu atomic - scale structures , we performed simulations based on the generalized gradient approximation in the density functional theory . an atomic layer of cu forming a triangular lattice ( tl ) was found to give a stable structure . the nitrogen monoxide molecule ( no ) was adsorbed on some atomic sites of tl or on an atomic step structure ( ass ) of cu . the molecular adsorption energy on tl was -0.83 ev . our data suggested that dissociative adsorption of no with a dissociation energy of -1.08 ev was possible with an energy barrier of order 1.4 ev . in this optimized structure , the nitrogen and oxygen atoms were embedded in the cu layer . on the step , no adsorbed at a bridge site and the formation energy of cu-(no)-cu local bond connections was estimated to be around -1.32 ev . molecular dissociation of no with a dissociation energy of -0.37 ev was also possible around ass .
| 170
|
astro-ph0511483
|
the origin and chemical composition of ultra high energy cosmic rays is still an open question in astroparticle physics . the observed large - scale isotropy and also direct composition measurements can be interpreted as an extragalactic proton dominance above the _ ankle _ at about @xmath0 gev . photopion production of extragalactic protons in the cosmic microwave background predicts a cutoff at about @xmath1 gev in conflict with excesses reported by some experiments . in this report we will outline a recent statistical analysis @xcite of cosmic ray data using strongly interacting neutrinos as primaries for these excesses .
| 100
|
1604.08362
|
we consider the markov random flight @xmath0 in the three - dimensional euclidean space @xmath1 with constant finite speed @xmath2 and the uniform choice of the initial and each new direction at random time instants that form a homogeneous poisson flow of rate @xmath3 . series representations for the conditional characteristic functions of @xmath4 corresponding to two and three changes of direction , are obtained . based on these results , an asymptotic formula , as @xmath5 , for the unconditional characteristic function of @xmath4 is derived . by inverting it , we obtain an asymptotic relation for the transition density of the process . we show that the error in this formula has the order @xmath6 and , therefore , it gives a good approximation on small time intervals whose lengths depend on @xmath7 . estimate of the accuracy of the approximation is analysed . * asymptotic relation for the transition density + of the three - dimensional markov random flight + on small time intervals * alexander d. kolesnik + institute of mathematics and computer science + academy street 5 , kishinev 2028 , moldova + e - mail : kolesnik@math.md 0.2 cm 0.1 cm _ keywords : _ markov random flight , persistent random walk , conditional density , fourier transform , characteristic function , asymptotic relation , transition density , small time intervals 0.2 cm _ ams 2010 subject classification : _ 60k35 , 60k99 , 60j60 , 60j65 , 82c41 , 82c70
| 247
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1602.05000
|
we present an analysis of intermediate - dispersion spectra and photometric data of the newly identified cool , polluted white dwarf nltt 19868 . the spectra obtained with x - shooter on the very large telescope ( vlt)-melipal show strong lines of calcium , and several lines of magnesium , aluminium and iron . we use these spectra and the optical - to - near infrared spectral energy distribution to constrain the atmospheric parameters of nltt 19868 . our analysis shows that nltt 19868 is iron poor with respect to aluminium and calcium . a comparison with other cool , polluted white dwarfs shows that the fe to ca abundance ratio ( fe / ca ) varies by up to approximately two orders of magnitudes over a narrow temperature range with nltt 19868 at one extremum in the fe / ca ratio and , in contrast , nltt 888 at the other extremum . the sample shows evidence of extreme diversity in the composition of the accreted material : in the case of nltt 888 , the inferred composition of the accreted matter is akin to iron - rich planetary core composition , while in the case of nltt 19868 it is close to mantle or bulk - earth composition depleted by subsequent chemical separation at the bottom of the convection zone . [ firstpage ] diffusion stars : abundances stars : atmospheres stars : individual ( nltt 888 , nltt 19868 ) white dwarfs
| 245
|
0810.4598
|
the remarkable sensitivity of the @xmath0-axis resistivity and magnetoresistance in cuprates to the spin ordering is used to clarify the doping - induced transformation from an antiferromagnetic ( af ) insulator to a superconducting ( sc ) metal in @xmath1ba@xmath2cu@xmath3o@xmath4 ( @xmath1@xmath5lu , y ) single crystals . the established phase diagram demonstrates that the af and sc regions apparently overlap : the superconductivity in @xmath1ba@xmath2cu@xmath3o@xmath4 , in contrast to la@xmath6sr@xmath7cuo@xmath8 , sets in before the long - range af order is completely destroyed by hole doping . magnetoresistance measurements of superconducting crystals with low @xmath9@xmath10@xmath11k give a clear view of the magnetic - field induced superconductivity suppression and recovery of the long - range af state . what still remains to be understood is whether the af order actually persists in the sc state or just revives when the superconductivity is suppressed , and , in the former case , whether the antiferromagnetism and superconductivity reside in nanoscopically separated phases or coexist on an atomic scale . keywords : phase diagram , antiferromagnetism , magnetoresistance , c - axis conductivity .
| 182
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math-ph0407034
|
using the formalism of rigorous statistical mechanics , we study the phenomena of phase separation and freezing - point depression upon freezing of solutions . specifically , we devise an ising - based model of a solvent - solute system and show that , in the ensemble with a fixed amount of solute , a macroscopic phase separation occurs in an interval of values of the chemical potential of the solvent . the boundaries of the phase separation domain in the phase diagram are characterized and shown to asymptotically agree with the formulas used in heuristic analyses of freezing point depression . the limit of infinitesimal concentrations is described in a subsequent paper . = 1
| 116
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0904.1879
|
we report on a multi - frequency , multi - epoch campaign of very long baseline interferometry observations of the radio galaxy 1946 + 708 using the vlba and a global vlbi array . from these high - resolution observations we deduce the kinematic age of the radio source to be @xmath04000 years , comparable with the ages of other compact symmetric objects ( csos ) . ejections of pairs of jet components appears to take place on time scales of 10 years and these components in the jet travel outward at intrinsic velocities between 0.6 and 0.9 c. from the constraint that jet components can not have intrinsic velocities faster than light , we derive @xmath1 @xmath2 57 km s@xmath3 mpc@xmath3 from the fastest pair of components launched from the core . we provide strong evidence for the ejection of a new pair of components in @xmath01997 . from the trajectories of the jet components we deduce that the jet is most likely to be helically confined , rather than purely ballistic in nature .
| 176
|
0909.4715
|
one of the open problems in higher category theory is the systematic construction of the higher dimensional analogues of the gray tensor product . in this paper we continue the work of @xcite to adapt the machinery of globular operads @xcite to this task . the resulting theory includes the gray tensor product of 2-categories and the crans tensor product @xcite of gray categories . moreover much of the previous work on the globular approach to higher category theory is simplified by our new foundations , and we illustrate this by giving an expedited account of many aspects of cheng s analysis @xcite of trimble s definition of weak @xmath0-category . by way of application we obtain an `` ekmann - hilton '' result for braided monoidal 2-categories , and give the construction of a tensor product of @xmath1-infinity algebras . [ multiblock footnote omitted ] [ multiblock footnote omitted ] [ multiblock footnote omitted ]
| 156
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hep-ph0405167
|
the longitudinal polarization of fermions ( tops and taus ) produced in sfermion decays to neutralinos or charginos can be a useful tool for the determination of susy parameters . we discuss this fermion polarization in the context of the mssm with complex parameters . we show that the dependence on cp - violating phases can be large and that the fermion polarization may hence be used as a sensitive probe of cp phases in the mssm . cern - ph - th/2004 - 086 + hephy - pub 790/04 + iisc - chep/7/04 + fi2004 - 15 + hep - ph/0405167 * fermion polarization in sfermion decays as + a probe of cp phases in the mssm * + thomas gajdosik@xmath0 , rohini m. godbole@xmath1 , sabine kraml@xmath2 + _ @xmath3 institute of physics , vilnius lt-2600 , lithuania + @xmath4 centre for high energy physics , indian institute of science , bangalore 560012 , india + @xmath5 inst . f. hochenergiephysik , sterr . akademie d. wissenschaften , 1050 vienna , austria + @xmath6 department of physics , cern , theory division , 1211 geneva 23 , switzerland + _
| 192
|
astro-ph9506066
|
we have observed an outburst of the t tauri star ex lup in march 1994 . we present both photometric ( bvr ) and spectroscopic ( low and medium resolution ) observations carried out during the decline after outburst . the star appears much bluer during outburst due to an increased emission of a hot continuum . this is accompanied by a strong increase of the veiling of photospheric lines . we observe inverse p cygni profiles of many emission lines over a large brightness range of ex lup . we briefly discuss these features towards the model of magnetospherically supported accretion of disk material . 2.5 cm # 1to -1.5pt#1
| 111
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1205.5710
|
the phase transition of the quantum spin-@xmath0 frustrated heisenberg antiferroferromagnet on an anisotropic square lattice is studied by using a variational treatment . the model is described by the heisenberg hamiltonian with two antiferromagnetic interactions : nearest - neighbor ( nn ) with different coupling strengths @xmath1 and @xmath2 along x and y directions competing with a next - nearest - neighbor coupling @xmath3 ( nnn ) . the ground state phase diagram in the ( @xmath4 ) space , where @xmath5 and @xmath6 , is obtained . depending on the values of @xmath7 and @xmath8 , we obtain three different states : antiferromagnetic ( * af * ) , collinear antiferromagnetic ( * caf * ) and quantum paramagnetic ( * qp * ) . for an intermediate region @xmath9 we observe a * qp * state between the ordered * af * and * caf * phases , which disappears for @xmath7 above some critical value @xmath10 . the boundaries between these ordered phases merge at the _ quantum critical endpoint _ ( * qce * ) . below this * qce * there is again a direct first - order transition between the * af * and * caf * phases , with a behavior approximately described by the classical line @xmath11 . * pacs numbers * : 75.10.jm , 05.30.-d , 75.40.-s , 75.40.cx
| 228
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1501.02852
|
we study the generalized mutual information @xmath0 of the ground state of different critical quantum chains . the generalized mutual information definition that we use is based on the well established concept of the rnyi divergence . we calculate this quantity numerically for several distinct quantum chains having either discrete @xmath1 symmetries ( q - state potts model with @xmath2 and @xmath1 parafermionic models with @xmath3 and also ashkin - teller model with different anisotropies ) or the @xmath4 continuous symmetries ( klein - gordon field theory , xxz and spin-1 fateev - zamolodchikov quantum chains with different anisotropies ) . for the spin chains these calculations were done by expressing the ground - state wavefunctions in two special basis . our results indicate some general behavior for particular ranges of values of the parameter @xmath5 that defines @xmath0 . for a system , with total size @xmath6 and subsystem sizes @xmath7 and @xmath8 , the @xmath0 has a logarithmic leading behavior given by @xmath9 where the coefficient @xmath10 is linearly dependent on the central charge @xmath11 of the underlying conformal field theory ( cft ) describing the system s critical properties .
| 193
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1703.08158
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a new numerical method is proposed for a 1-d inverse medium scattering problem with multi - frequency data . this method is based on the construction of a weighted cost functional . the weight is a carleman weight function ( cwf ) . in other words , this is the function , which is present in the carleman estimate for the undelying differential operator . the presence of the cwf makes this functional strictly convex on any a priori chosen ball with the center at @xmath0 in an appropriate hilbert space . convergence of the gradient minimization method to the exact solution starting from any point of that ball is proven . computational results for both computationally simulated and experimental data show a good accuracy of this method . * key words * : global convergence , coefficient inverse problem , multi - frequency data , carleman weight function * 2010 mathematics subject classification : * 35r30 .
| 158
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1701.00774
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given a real number @xmath0 , we study the associated @xmath1-shift introduced in @xcite . we compares some aspects of the @xmath2-shift to the @xmath3-shift . when the expansion in base @xmath4 of @xmath5 is periodic with odd period or when @xmath6 is strictly less than the golden ratio , the @xmath1-shift , as defined in @xcite can not be coded because its language is not transitive . this intransitivity of words explains the existence of gaps in the interval . we observe that an intransitive word appears in the @xmath2-expansion of a real number taken in the gap . furthermore , we determine the zeta function @xmath7 of the @xmath2-transformation and the associated lap - counting function @xmath8 . these two functions are related by @xmath9 . we observe some similarities with the zeta function of the @xmath3-transformation . the function @xmath7 is meromorphic in the unit disk , is holomorphic in the open disk @xmath10 , has a simple pole at @xmath11 and no other singularities @xmath12 such that @xmath13 . we also note an influence of gaps ( @xmath3 less than the golden ratio ) on the zeta function . in factors of the denominator of @xmath7 , the coefficients count the words generating gaps .
| 209
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1205.0614
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the sunspot number varies roughly periodically with time . however the individual cycle durations and the amplitudes are found to vary in an irregular manner . it is observed that the stronger cycles are having shorter rise times and vice versa . this leads to an important effect know as the waldmeier effect . another important feature of the solar cycle irregularity are the grand minima during which the activity level is strongly reduced . we explore whether these solar cycle irregularities can be studied with the help of the flux transport dynamo model of the solar cycle . we show that with a suitable stochastic fluctuations in a regular dynamo model , we are able to reproduce many irregular features of the solar cycle including the waldmeier effect and the grand minimum . however , we get all these results only if the value of the turbulent diffusivity in the convection zone is reasonably high . [ firstpage ]
| 160
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1510.00115
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phylogenetic networks are mathematical structures for modeling and visualization of reticulation processes in the study of evolution . galled networks , reticulation visible networks , nearly - stable networks and stable - child networks are the four classes of phylogenetic networks that are recently introduced to study the topological and algorithmic aspects of phylogenetic networks . we prove the following results . * a binary galled network with @xmath0 leaves has at most @xmath1 reticulation nodes . * a binary nearly - stable network with @xmath0 leaves has at most @xmath2 reticulation nodes . * a binary stable - child network with @xmath0 leaves has at most @xmath3 reticulation nodes .
| 111
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physics0109012
|
electron injection from an adsorbed molecule to the substrate ( heterogeneous electron transfer ) is studied . one reaction coordinate is used to model this process . the surface phonons and/or the electron - hole pairs together with the internal degrees of freedom of the adsorbed molecule as well as possibly a liquid surrounding the molecule provide a dissipative environment , which may lead to dephasing , relaxation , and sometimes excitation of the relevant system . in the process studied the adsorbed molecule is excited by a light pulse . this is followed by an electron transfer from the excited donor state to the quasi - continuum of the substrate . it is assumed that the substrate is a semiconductor . the effects of dissipation on electron injection are investigated . electron transfer , density matrix theory , molecules at surfaces
| 142
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1006.3484
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recent studies of lensing clusters reveal that it might be fairly common for a galaxy cluster that the x - ray center has an obvious offset from its gravitational center which is measured by strong lensing . we argue that if these offsets exist , then x - rays and lensing are indeed measuring different regions of a cluster , and may thus naturally result in a discrepancy in the measured gravitational masses by the two different methods . here we investigate theoretically the dynamical effects of such lensing - x - ray offsets , and compare with observational data . we find that for typical values , the offset alone can give rise to a factor of two difference between the lensing and x - ray determined masses for the core regions of a cluster , suggesting that such `` offset effect '' may play an important role and should not be ignored in our dynamical measurements of clusters . [ firstpage ] dark matter - gravitational lensing - x - rays : galaxies : clusters
| 177
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1609.00244
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we study a family of double confluent heun equations that are linearizations of nonlinear equations on two - torus modeling the josephson effect in superconductivity . they have the form @xmath0 , where @xmath1 is a family of differential operators of order two acting on germs of holomorphic functions in one complex variable . they depend on parameters @xmath2 , @xmath3 , @xmath4 . we show that for every @xmath5 and @xmath6 satisfying a certain `` non - resonance condition '' and every parameter values @xmath7 , @xmath8 there exists a unique entire function @xmath9 ( up to multiplicative constant ) such that @xmath10 for some @xmath11 . the latter @xmath12 are expressed as functions of the parameters . this result has several applications . first of all , it gives the description of those parameter values for which the monodromy operator of the corresponding heun equation has given eigenvalues . this yields the description of the non - integer level curves of the rotation number of the family of equations on two - torus as a function of parameters . in the particular case , when the monodromy is parabolic ( has multiple eigenvalue ) , we get the complete description of those parameter values that correspond to the boundaries of the phase - lock areas : integer level sets of the rotation number , which have non - empty interiors .
| 233
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0707.4010
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the stability of a recently proposed general relativistic model of galaxies is studied in some detail . this model is a general relativistic version of the well known miyamoto - nagai model that represents well a thick galactic disk . the stability of the disk is investigated under a general first order perturbation keeping the spacetime metric frozen ( no gravitational radiation is taken into account ) . we find that the stability is associated with the thickness of the disk . we have that flat galaxies have more not - stable modes than the thick ones i.e. , flat galaxies have a tendency to form more complex structures like rings , bars and spiral arms . [ firstpage ] relativity galaxies : kinematics and dynamics
| 126
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1404.4800
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* _ abstract _ : * in this paper , we present a new pipeline which automatically identifies and annotates axoplasmic reticula , which are small subcellular structures present only in axons . we run our algorithm on the kasthuri11 dataset , which was color corrected using gradient - domain techniques to adjust contrast . we use a bilateral filter to smooth out the noise in this data while preserving edges , which highlights axoplasmic reticula . these axoplasmic reticula are then annotated using a morphological region growing algorithm . additionally , we perform laplacian sharpening on the bilaterally filtered data to enhance edges , and repeat the morphological region growing algorithm to annotate more axoplasmic reticula . we track our annotations through the slices to improve precision , and to create long objects to aid in segment merging . this method annotates axoplasmic reticula with high precision . our algorithm can easily be adapted to annotate axoplasmic reticula in different sets of brain data by changing a few thresholds . the contribution of this work is the introduction of a straightforward and robust pipeline which annotates axoplasmic reticula with high precision , contributing towards advancements in automatic feature annotations in neural em data . + 2
| 207
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1105.2699
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the recent data on @xmath0dijet excess reported by cdf may be interpreted as the associated production of a @xmath1 and a new particle of mass about 150 gev which subsequently decays into two hadron jets . we study the possibility of explaining the @xmath0dijet excess by colored scalar bosons . there are several colored scalars which can have tree level renormalizable yukawa couplings with two quarks , @xmath2 , @xmath3 , @xmath4 . if one of these scalars has a mass about 150 gev , being colored it can naturally explain why the excess only shows up in the form of two hadron jets . although the required production cross section and mass put constraints on model parameters and rule out some possible scenarios when confronted with other existing data , in particular fcnc data , we find that there are strong constraints on the yukawa couplings of these scalars . without forcing the couplings to be some special texture forms most of the scalars , except the @xmath5 , are in trouble with fcnc data . we also study some features for search of these new particles at the rhic and the lhc and find that related information can help further to distinguish different models .
| 207
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astro-ph0110094
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we present a statistical x - ray study of spiral galaxies in the hubble deep field - north and its flanking fields using the chandra deep field north 1 ms dataset . we find that @xmath0 galaxies with @xmath1 have ratios of x - ray to @xmath2-band luminosity similar to those in the local universe , although the data indicate a likely increase in this ratio by a factor of @xmath33 . we have also determined that typical spiral galaxies at @xmath1 should be detected in the 0.52 kev band in the flux range ( @xmath46@xmath5 erg @xmath6 s@xmath7 . 1_heao-1 _
| 102
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1209.0930
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the asymmetric spin - orbit interactions play a crucial role in realizing topological phases in noncentrosymmetric superconductor ( ncs ) . we investigate the edge states and the vortex core states in the @xmath0-wave ncs with dresselhaus ( 110 ) spin - orbit coupling by both numerical and analytical methods . in particular , we demonstrate that there exists a novel semimetal phase characterized by the flat andreev bound states in the phase diagram of the @xmath0-wave dresselhaus ncs which supports the emergence of majorana fermions . the flat dispersion implies a peak in the density of states which has a clear experimental signature in the tunneling conductance measurements and the majorana fermions proposed here should be experimentally detectable .
| 120
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0802.4262
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an important concern in the application of gamma - ray bursts ( grbs ) to cosmology is that the calibration of grb luminosity / energy relations depends on the cosmological model , due to the lack of a sufficient low - redshift grb sample . in this paper , we present a new method to calibrate grb relations in a cosmology - independent way . since objects at the same redshift should have the same luminosity distance and since the distance moduli of type ia supernovae ( sne ia ) obtained directly from observations are completely cosmology independent , we obtain the distance modulus of a grb at a given redshift by interpolating from the hubble diagram of sne ia . then we calibrate seven grb relations without assuming a particular cosmological model and construct a grb hubble diagram to constrain cosmological parameters . from the 42 grbs at @xmath0 , we obtain @xmath1 , @xmath2 for the flat @xmath3cdm model , and for the dark energy model with a constant equation of state @xmath4 , which is consistent with the concordance model in a 1-@xmath5 confidence region .
| 189
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1411.1517
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the question of which two - qubit states are steerable ( i.e. permit a demonstration of epr - steering ) remains open . here , a strong necessary condition is obtained for the steerability of two - qubit states having maximally - mixed reduced states , via the construction of local hidden state models . it is conjectured that this condition is in fact sufficient . two provably sufficient conditions are also obtained , via asymmetric epr - steering inequalities . our work uses ideas from the quantum steering ellipsoid formalism , and explicitly evaluates the integral of @xmath0 over arbitrary unit hemispheres for any positive matrix @xmath1 .
| 109
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1006.2415
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although the generation of disoriented chiral condensates ( dccs ) , where the order parameter for chiral symmetry breaking is misaligned with respect to the vacuum direction in isospin state , is quite natural in the theory of strong interactions , they have so far eluded experiments in accelerators and cosmic rays . if dccs are formed in high - energy nuclear collisions , the relevant outcome are very large event - by - event fluctuations in the neutral - to - charged pion fraction . in this note we search for fingerprints of dcc formation in observables of ultra - high energy cosmic ray showers . we present simulation results for the depth of the maximum ( @xmath0 ) and number of muons on the ground , evaluating their sensitivity to the neutral - to - charged pion fraction asymmetry produced in the primary interaction .
| 147
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0907.0231
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we study the cool gas around a galaxy at @xmath0 using keck / lris spectroscopy of a bright ( @xmath1 ) background galaxy at @xmath2 at a transverse distance of @xmath3 kpc . the background galaxy spectrum reveals strong , , , and absorption at the redshift of the foreground galaxy , with a @xmath4 rest equivalent width of @xmath5 , indicative of a velocity width exceeding @xmath6 . because the background galaxy is large ( @xmath7 kpc ) , the high covering fraction of the absorbing gas suggests that it arises in a spatially extended complex of cool clouds with large velocity dispersion . spectroscopy of the massive ( @xmath8 ) host galaxy reveals that it experienced a burst of star formation about 1 gyr ago and that it harbors a weak agn . we discuss the possible origins of the cool gas in its halo , including multiphase cooling of hot halo gas , cold inflow , tidal interactions , and galactic winds . we conclude the absorbing gas was most likely ejected or tidally stripped from the interstellar medium of the host galaxy or its progenitors during the past starburst event . adopting the latter interpretation , these results place one of only a few constraints on the radial extent of cool gas driven or stripped from a galaxy in the distant universe . future studies with integral field unit spectroscopy of spatially extended background galaxies will provide multiple sightlines through foreground absorbers and permit analysis of the morphology and kinematics of the gas surrounding galaxies with a diverse set of properties and environments .
| 268
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cond-mat0602604
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we propose a scheme for tunable coupling of phase - coupled flux qubits . the phase - coupling scheme can provide a strong coupling strength of the order of josephson coupling energy of josephson junctions in the connecting loop , while the previously studied inductive coupling scheme can not provide due to small mutual inductance and induced currents . we show that , in order to control the coupling , we need _ two _ dc - squid s in the connecting loop and the control fluxes threading the dc - squid s must be in _ opposite _ directions . the coupling strength is analytically calculated as a function of the control flux at the co - resonance point .
| 121
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1504.08321
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proposition algebra is based on hoare s conditional connective , which is a ternary connective comparable to if - then - else and used in the setting of propositional logic . conditional statements are provided with a simple semantics that is based on evaluation trees and that characterizes so - called free valuation congruence : two conditional statements are free valuation congruent if , and only if , they have equal evaluation trees . free valuation congruence is axiomatized by the four basic equational axioms of proposition algebra that define the conditional connective . valuation congruences that identify more conditional statements than free valuation congruence are repetition - proof , contractive , memorizing , and static valuation congruence . each of these valuation congruences is characterized using a transformation on evaluation trees : two conditional statements are c - valuation congruent if , and only if , their c - transformed evaluation trees are equal . these transformations are simple and natural , and only for static valuation congruence a slightly more complex transformation is used . also , each of these valuation congruences is axiomatized in proposition algebra . a spin - off of our approach is `` basic form semantics for proposition algebra '' : for each valuation congruence c considered , two conditional statements are c - valuation congruent if , and only if , they have equal c - basic forms , where c - basic forms are obtained by a syntactic transformation of conditional statements , which is a form of normalization . conditional composition , evaluation tree , proposition algebra , short - circuit evaluation , side effect
| 274
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cond-mat0703646
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a theoretical study is presented of surface waves at a monomolecular surfactant film between an isotropic liquid and a nematic liquid crystal for the case when the surfactant film is in the isotropic two - dimensional fluid phase and induces homeotropic ( normal to the interface ) orientation of the nematic director . the dispersion relation for the surface waves is obtained , and different surface modes are analyzed with account being taken of the anchoring induced by the surfactant layer , the curvature energy of the interface , and the anisotropy of the viscoelastic coefficients . the dispersion laws for capillary and dilatational surface modes retain structure similar to that in isotropic systems , but involve anisotropic viscosity coefficients . additional modes are related to relaxation of the nematic director field due to anchoring at the interface . the results can be used to determine different properties of nematic - surfactant - isotropic interfaces from experimental data on surface light scattering .
| 163
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1210.3986
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the last part of sps5 dealt with the circumstellar environment . structures are indeed found around several types of massive stars , such as blue and red supergiants , as well as wrs and lbvs . as shown in the last years , the potential of ir for their study is twofold : first , ir can help discover many previously unknown nebulae , leading to the identification of new massive stars as their progenitors ; second , ir can help characterize the nebular features . current and new ir facilities thus pave the way to a better understanding of the feedback from massive stars .
| 106
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astro-ph9807334
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this paper presents the i - band data obtained by the eso imaging survey ( eis ) over two patches of the sky , 6 square degrees each , centered at @xmath0 , @xmath1 , and @xmath2 , @xmath3 . the data are being made public in the form of object catalogs and , photometrically and astrometrically calibrated pixel maps . these products together with other useful information can be found at `` http://www.eso.org/eis '' . the overall quality of the data in the two fields is significantly better than the other two patches released earlier and cover a much larger contiguous area . the total number of objects in the catalogs extracted from these frames is over 700,000 down to @xmath4 , where the galaxy catalogs are 80% complete . the star counts are consistent with model predictions computed at the position of the patches considered . the galaxy counts and the angular two - point correlation functions are also consistent with those of the other patches showing that the eis data set is homogeneous and that the galaxy catalogs are uniform . 1@xmath5 # 1
| 187
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1607.08062
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a multi - resolution bead - spring model for polymer dynamics is developed as a generalization of the rouse model . a polymer chain is described using beads of variable sizes connected by springs with variable spring constants . a numerical scheme which can use different timesteps to advance the positions of different beads is presented and analyzed . the position of a particular bead is only updated at integer multiples of the timesteps associated with its connecting springs . this approach extends the rouse model to a multiscale model on both spatial and temporal scales , allowing simulations of localized regions of a polymer chain with high spatial and temporal resolution , while using a coarser modelling approach to describe the rest of the polymer chain . a method for changing the model resolution on - the - fly is developed using the metropolis - hastings algorithm . it is shown that this approach maintains key statistics of the end - to - end distance and diffusion of the polymer filament and makes computational savings when applied to a model for the binding of a protein to the dna filament . polymer dynamics , dna , rouse model , brownian dynamics , multiscale modelling 60h10 , 60j70 , 82c31 , 82d60 , 92b99
| 214
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0710.5614
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interval exchange maps are related to geodesic flows on translation surfaces ; they correspond to the first return maps of the vertical flow on a transverse segment . the rauzy - veech induction on the space of interval exchange maps provides a powerful tool to analyze the teichmller geodesic flow on the moduli space of abelian differentials . several major results have been proved using this renormalization . danthony and nogueira introduced in @xmath0 a natural generalization of interval exchange transformations , namely the linear involutions . these maps are related to general measured foliations on surfaces ( orientable or not ) . in this paper we are interested by such maps related to geodesic flow on ( orientable ) flat surfaces with @xmath1 linear holonomy . we relate geometry and dynamics of such maps to the combinatorics of generalized permutations . we study an analogue of the rauzy - veech induction and give an efficient combinatorial characterization of its attractors . we establish a natural bijection between the extended rauzy classes of generalized permutations and connected components of the strata of meromorphic quadratic differentials with at most simple poles , which allows , in particular , to classify the connected components of all exceptional strata .
| 207
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astro-ph0212125
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we investigate if consequential angular momentum losses ( caml ) or an intrinsic deformation of the donor star in cvs could increase the cv bounce period from the canonical theoretical value @xmath0 min to the observed value @xmath1 min , and if a variation of these effects in a cv population could wash out the theoretically predicted accumulation of systems near the minimum period ( the period spike ) . we are able to construct suitably mixed cv model populations that a statisticial test can not rule out as the parent population of the observed cv sample . however , the goodness of fit is never convincing , and always slightly worse than for a simple , flat period distribution . generally , the goodness of fit is much improved if all cvs are assumed to form at long orbital periods . the weighting suggested by king , schenker & hameury ( 2002 ) does not constitute an improvment if a realistically shaped input period distribution is used . binaries : close stars : evolution stars : mass - loss novae , cataclysmic variables .
| 185
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1009.0990
|
the nonlinear propagation of electromagnetic ( em ) electron - cyclotron waves ( whistlers ) along an external magnetic field , and their modulation by electrostatic small but finite amplitude ion - acoustic density perturbations are investigated in a uniform quantum plasma with intrinsic spin of electrons . the effects of the quantum force associated with the bohm potential and the combined effects of the classical as well as the spin - induced ponderomotive forces ( cpf and spf respectively ) are taken into consideration . the latter modify the local plasma density in a self - consistent manner . the coupled modes of wave propagation is shown to be governed by a modified set of nonlinear schrdinger - boussinesq - like equations which admit exact solutions in form of stationary localized envelopes . numerical simulation reveals the existence of large - scale density fluctuations that are self - consistently created by the localized whistlers in a strongly magnetized high density plasma . the conditions for the modulational instability ( mi ) and the value of its growth rate are obtained . possible applications of our results , e.g. , in strongly magnetized dense plasmas and in the next generation laser - solid density plasma interaction experiments are discussed .
| 210
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1208.4880
|
we report on the results of a direct @xmath0-body simulation of a star cluster that started with @xmath1 , comprising @xmath2 single stars and @xmath3 primordial binaries . the code used for the simulation includes stellar evolution , binary evolution , an external tidal field and the effects of two - body relaxation . the model cluster is evolved to @xmath4gyr , losing more than 80% of its stars in the process . it reaches the end of the main core - collapse phase at @xmath5gyr and experiences core oscillations from that point onwards direct numerical confirmation of this phenomenon . however , we find that after a further @xmath6gyr the core oscillations are halted by the ejection of a massive binary comprised of two black holes from the core , producing a core that shows no signature of the prior core - collapse . we also show that the results of previous studies with @xmath0 ranging from @xmath7 to @xmath8 scale well to this new model with larger @xmath0 . in particular , the timescale to core - collapse ( in units of the relaxation timescale ) , mass segregation , velocity dispersion , and the energies of the binary population all show similar behaviour at different @xmath0 . [ firstpage ] stars : evolution globular clusters : general galaxies : star clusters : general methods : numerical binaries : close stars : kinematics and dynamics
| 237
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0709.3038
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nuclear parton distribution functions ( npdfs ) are determined by global analyses of experimental data on structure - function ratios @xmath0 and drell - yan cross - section ratios @xmath1 . the analyses are done in the leading order ( lo ) and next - to - leading order ( nlo ) of running coupling constant @xmath2 . uncertainties of the npdfs are estimated in both lo and nlo for finding possible nlo improvement . valence - quark distributions are well determined , and antiquark distributions are also determined at @xmath3 . however , the antiquark distributions have large uncertainties at @xmath4 . gluon modifications can not be fixed at this stage . although the advantage of the nlo analysis , in comparison with the lo one , is generally the sensitivity to the gluon distributions , gluon uncertainties are almost the same in the lo and nlo . it is because current scaling - violation data are not accurate enough to determine precise nuclear gluon distributions . modifications of the pdfs in the deuteron are also discussed by including data on the proton - deuteron ratio @xmath5 in the analysis . a code is provided for calculating the npdfs and their uncertainties at given @xmath6 and @xmath7 in the lo and nlo .
| 214
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math0607386
|
let @xmath0 be an oriented surface of genus @xmath1 with @xmath2 punctures and @xmath3 . we construct an uncountable family of probability measures on the space @xmath4 of area one holomorphic quadratic differentials over the moduli space for @xmath0 containing the usual lebesgue measure . these measures are invariant under the teichmller geodesic flow @xmath5 , and they are mixing , absolutely continuous with respect to the stable and unstable foliation and exponentially recurrent to a compact set . we show that the critical exponent of the mapping class group equals @xmath6 . moreover , this critical exponent coincides with the logarithmic asymptotic for the number of closed teichmller geodesics in moduli space which meet a sufficiently large compact set .
| 121
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hep-th0602016
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we study the thermodynamics of small black holes in compactified spacetimes of the form @xmath0 . this system is analyzed with the aid of an effective field theory ( eft ) formalism in which the structure of the black hole is encoded in the coefficients of operators in an effective worldline lagrangian . in this effective theory , there is a small parameter @xmath1 that characterizes the corrections to the thermodynamics due to both the non - linear nature of the gravitational action as well as effects arising from the finite size of the black hole . using the power counting of the eft we show that the series expansion for the thermodynamic variables contains terms that are analytic in @xmath1 , as well as certain fractional powers that can be attributed to finite size operators . in particular our operator analysis shows that existing analytical results do not probe effects coming from horizon deformation . as an example , we work out the order @xmath2 corrections to the thermodynamics of small black holes for arbitrary @xmath3 , generalizing the results in the literature .
| 185
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nucl-th0612072
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superscaling analysis of electroweak nuclear response functions is done for momentum transfer values from 300 to 700 mev / c . some effects , absent in the relativistic fermi gas model , where the superscaling holds by construction , are considered . from the responses calculated for the @xmath0c , @xmath1o and @xmath2ca nuclei , we have extracted a theoretical universal superscaling function similar to that obtained from the experimental responses . theoretical and empirical universal scaling functions have been used to calculate electron and neutrino cross sections . these cross sections have been compared with those obtained with a complete calculation and , for the electron scattering case , with the experimental data .
| 115
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1603.05788
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the complexity of the equation solvability problem is known for nilpotent groups , for not solvable groups and for some semidirect products of abelian groups . we provide a new polynomial time algorithm for deciding the equation solvability problem over certain semidirect products , where the first factor is not necessarily abelian . our main idea is to represent such groups as matrix groups , and reduce the original problem to equation solvability over the underlying field . further , we apply this new method to give a much more efficient algorithm for equation solvability over nilpotent rings than previously existed .
| 102
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astro-ph0003353
|
we present new , high resolution , infrared spectra of the t dwarf gliese 229b in the @xmath0 , @xmath1 , and @xmath2 bandpasses . we analyze each of these as well as previously published spectra to determine its metallicity and the abundances of nh@xmath3 and co in terms of the surface gravity of gl 229b , which remains poorly constrained . the metallicity increases with increasing gravity and is below the solar value unless gl 229b is a high - gravity brown dwarf with @xmath4 . the nh@xmath3 abundance is determined from both the @xmath1 and the @xmath2 band spectra which probe two different levels in the atmosphere . we find that the abundance from the @xmath2 band data is well below that expected from chemical equilibrium , which we interpret as strong evidence for dynamical transport of nh@xmath3 in the atmosphere . this is consistent with the previous detection of co and provides additional constraints on the dynamics of the atmosphere of this t dwarf . # 1 10^#1 # 1 # 1(#1_1, ,#1_n ) # 1d#1_1 d#1_n 1nu^n_1 # 1#1 _ 0 2h2 _ 2 _ # 1#2 # 1_k_#1 # 1
| 195
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hep-th0211232
|
system of a d - brane in bosonic string theory on a constant @xmath0 field background is studied in order to obtain further insight into the bulk - boundary duality . boundary states which describe arbitrary numbers of open - string tachyons and gluons are given . uv behaviors of field theories on the non - commutative world - volume are investigated by using these states . we take zero - slope limits of generating functions of one - loop amplitudes of gluons ( and open - string tachyons ) in which the region of the small open - string proper time is magnified . existence of @xmath0 field allows the limits to be slightly different from the standard field theory limits of closed - string . they enable us to capture world - volume theories at a trans - string scale . in this limit the generating functions are shown to be factorized by two curved open wilson lines ( and their analogues ) and become integrals on the space of paths with a gaussian distribution around straight lines . these indicate a possibility that field theories on the non - commutative world - volume are topological at such a trans - string scale . we also give a proof of the dhar - kitazawa conjecture by making an explicit correspondence between the closed - string states and the paths . momentum eigenstates of closed - string or momentum loops also play an important role in these analyses . mifp-02 - 09 + ou - het 418 + hep - th/0211232 + november 2002 * open wilson lines as states of closed string * + koichi murakami + toshio nakatsu + [ section ] [ section ] [ section ] [ section ] [ section ] [ section ]
| 300
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0909.1876
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this work proposes a general framework for the design and simulation of network on chip based turbo decoder architectures . several parameters in the design space are investigated , namely the network topology , the parallelism degree , the rate at which messages are sent by processing nodes over the network and the routing strategy . the main results of this analysis are : i ) the most suited topologies to achieve high throughput with a limited complexity overhead are generalized de - bruijn and generalized kautz topologies ; ii ) depending on the throughput requirements different parallelism degrees , message injection rates and routing algorithms can be used to minimize the network area overhead .
| 116
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1408.5810
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this paper introduces kernel - based information criterion ( kic ) for model selection in regression analysis . the novel kernel - based complexity measure in kic efficiently computes the interdependency between parameters of the model using a variable - wise variance and yields selection of better , more robust regressors . experimental results show superior performance on both simulated and real data sets compared to leave - one - out cross - validation ( loocv ) , kernel - based information complexity ( icomp ) , and maximum log of marginal likelihood in gaussian process regression ( gpr ) .
| 101
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1308.2688
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american options in a multi - asset market model with proportional transaction costs are studied in the case when the holder of an option is able to exercise it gradually at a so - called mixed ( randomised ) stopping time . the introduction of gradual exercise leads to tighter bounds on the option price when compared to the case studied in the existing literature , where the standard assumption is that the option can only be exercised instantly at an ordinary stopping time . algorithmic constructions for the bid and ask prices and the associated superhedging strategies and optimal mixed stoping times for an american option with gradual exercise are developed and implemented , and dual representations are established .
| 121
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1510.07571
|
the no@xmath0a collaboration has constructed a 14,000 ton , fine - grained , low - z , total absorption tracking calorimeter at an off - axis angle to an upgraded numi neutrino beam . this detector , with its excellent granularity and energy resolution and relatively low - energy neutrino thresholds , was designed to observe electron neutrino appearance in a muon neutrino beam , but it also has unique capabilities suitable for more exotic efforts . in fact , if an efficient upward - going muon trigger with sufficient cosmic ray background rejection can be demonstrated , no@xmath0a will be capable of a competitive indirect dark matter search for low - mass wimps . the cosmic ray muon rate at the no@xmath0a far detector is about 100 khz and provides the primary challenge for triggering and optimizing such a search analysis . the status of the no@xmath0a upward - going muon trigger is presented .
| 156
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cond-mat0207090
|
the structural energetics of pdti and ptti have been studied using first - principles density - functional theory with pseudopotentials and a plane - wave basis . we predict that in both materials , the experimentally reported orthorhombic @xmath0 phase will undergo a low - temperature phase transition to a monoclinic @xmath1 ground state . within a soft - mode framework , we relate the @xmath0 structure to the cubic @xmath2 structure , observed at high temperature , and the @xmath1 structure to @xmath0 via phonon modes strongly coupled to strain . in contrast to niti , the @xmath0 structure is extremely close to hcp . we draw on the analogy to the bcc - hcp transition to suggest likely transition mechanisms in the present case .
| 127
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quant-ph0011024
|
we have investigated the efficiency of pulsed raman sideband cooling in the presence of multiple decay and excitation channels . by applying sum rules we identify parameter regimes in which multiple scattering of photons can be described by an effective wave vector . using this method we determine the rate of heating caused by optical pumping inside and outside the lamb - dicke regime . on this basis we discuss also the efficiency of a recently proposed scheme for ground - state cooling outside the lamb - dicke regime [ g. morigi , j.i . cirac , m. lewenstein , and p. zoller , europhys . lett . * 39 * , 13 ( 1997 ) ] .
| 118
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astro-ph0211378
|
we report the detection of a feature at 65@xmath0 m and a broad feature around 100@xmath0 m in the far - infrared spectra of the diffuse emission from two active star - forming regions , and . the features are seen in the spectra over a wide area of the observed regions , indicating that the carriers are fairly ubiquitous species in the interstellar medium . a similar 65@xmath0 m feature has been detected in evolved stars and attributed to diopside , a ca - bearing crystalline silicate . the present observations indicate the first detection of a crystalline silicate in the interstellar medium if this identification holds true also for the interstellar feature . a similar broad feature around 90@xmath0 m reported in the spectra of evolved stars has been attributed to calcite , a ca - bearing carbonate mineral . the interstellar feature seems to be shifted to longer wavelengths and have a broader width although the precise estimate of the feature profile is difficult . as a carrier for the interstellar 100@xmath0 m feature , we investigate the possibility that the feature originates from carbon onions , grains consisting of curved graphitic shells . because of the curved graphitic sheet structure , the optical properties in the direction parallel to the graphitic plane interacts with those in the vertical direction in carbon onion grains . this effect enhances the interband transition feature in the direction parallel to the graphitic plane in carbon onions , which is suppressed in graphite particles . simple calculations suggest that carbon onion grains are a likely candidate for the observed 100@xmath0 m feature carrier , but the appearance of the feature is sensitive to the assumed optical properties .
| 287
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nucl-th0206008
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we investigate the possible signature of the presence of giant pairing states at excitation energy of about 10 mev via two - particle transfer reactions induced by neutron - rich weakly - bound projectiles . performing particle - particle rpa calculations on @xmath0pb and bcs+rpa calculations on @xmath1sn , we obtain the pairing strength distribution for two particles addition and removal modes . estimates of two - particle transfer cross sections can be obtained in the framework of the macroscopic model. the weak - binding nature of the projectile kinematically favours transitions to high - lying states . in the case of @xmath2 reaction we predict a population of the giant pairing vibration with cross sections of the order of a millibarn , dominating over the mismatched transition to the ground state .
| 133
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1511.02959
|
the first observations by a worldwide network of advanced interferometric gravitational wave detectors offer a unique opportunity for the astronomical community . at design sensitivity , these facilities will be able to detect coalescing binary neutron stars to distances approaching , and neutron star - black hole systems to . both of these sources are associated with gamma ray bursts which are known to emit across the entire electromagnetic spectrum . gravitational wave detections provide the opportunity for `` multi - messenger '' observations , combining gravitational wave with electromagnetic , cosmic ray or neutrino observations . this review provides an overview of how australian astronomical facilities and collaborations with the gravitational wave community can contribute to this new era of discovery , via contemporaneous follow - up observations from the radio to the optical and high energy . we discuss some of the frontier discoveries that will be made possible when this new window to the universe is opened . binaries : close gravitational waves gamma - ray burst : general methods : observational supernovae : general stars : neutron
| 181
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0910.2005
|
in this paper , we consider modulation codes for practical multilevel flash memory storage systems with @xmath0 cell levels . instead of maximizing the lifetime of the device @xcite , we maximize the average amount of information stored per cell - level , which is defined as storage efficiency . using this framework , we show that the worst - case criterion @xcite and the average - case criterion @xcite are two extreme cases of our objective function . a self - randomized modulation code is proposed which is asymptotically optimal , as @xmath1 , for an arbitrary input alphabet and i.i.d . input distribution . in practical flash memory systems , the number of cell - levels @xmath0 is only moderately large . so the asymptotic performance as @xmath1 may not tell the whole story . using the tools from load - balancing theory , we analyze the storage efficiency of the self - randomized modulation code . the result shows that only a fraction of the cells are utilized when the number of cell - levels @xmath0 is only moderately large . we also propose a load - balancing modulation code , based on a phenomenon known as `` the power of two random choices '' @xcite , to improve the storage efficiency of practical systems . theoretical analysis and simulation results show that our load - balancing modulation codes can provide significant gain to practical flash memory storage systems . though pseudo - random , our approach achieves the same load - balancing performance , for i.i.d . inputs , as a purely random approach based on the power of two random choices .
| 277
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1004.1216
|
a ( non - circular ) de bruijn sequence @xmath0 of order @xmath1 is a word such that every word of length @xmath1 appears exactly once in @xmath0 as a factor . in this paper , we generalize the concept to a multi - shift setting : a @xmath2-shift de bruijn sequence of order @xmath1 is a word such that every word of length @xmath1 appears exactly once in @xmath0 as a factor that starts at an index @xmath3 for some integer @xmath4 . we show the number of the @xmath2-shift de bruijn sequences of order @xmath1 is @xmath5 for @xmath6 and is @xmath7 for @xmath8 , where @xmath9 is the size of the alphabet . we provide two algorithms for generating a multi - shift de bruijn sequence . the multi - shift de bruijn sequence is important in solving the frobenius problem in a free monoid .
| 149
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cond-mat0602246
|
transport measurements are presented on a quantum ring that is tunnel - coupled to a quantum dot . when the dot is in the coulomb blockade regime , but strongly coupled to the open ring , fano line shapes are observed in the current through the ring , when the electron number in the dot changes by one . the symmetry of the fano resonances is found to depend on the magnetic flux penetrating the area of the ring and on the strength of the ring dot coupling . at temperatures above t=0.65k the fano effect disappears while the aharonov bohm interference in the ring persists up to t=4.2k . good agreement is found between these experimental observations and a single - channel scattering matrix model including decoherence in the dot .
| 132
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quant-ph0006047
|
it is not possible to disentangle a qubit in an _ unknown _ state @xmath0 from a set of @xmath1 ancilla qubits prepared in a specific reference state @xmath2 . that is , it is not possible to _ perfectly _ perform the transformation @xmath3 . the question is then how well we can do ? we consider a number of different methods of extracting an unknown state from an entangled state formed from that qubit and a set of ancilla qubits in an known state . measuring the whole system is , as expected , the least effective method . we present various quantum `` devices '' which disentangle the unknown qubit from the set of ancilla qubits . in particular , we present the _ optimal universal _ disentangler which disentangles the unknown qubit with the fidelity which does not depend on the state of the qubit , and a probabilistic disentangler which performs the perfect disentangling transformation , but with a probability less than one . * pacs number : 03.67.-a , 03.65.bz * 2
| 178
|
1305.5466
|
the analysis of the recent charged - current neutrino - nucleus scattering cross sections measured by the argoneut collaboration requires relativistic theoretical descriptions also accounting for the role of final - state interactions . in this work , we evaluate differential neutrino - nucleus cross sections with the relativistic green s function model , where final - state interactions are described in the inclusive scattering consistently with the exclusive scattering using a complex optical potential . the sensitivity to the parameterization adopted for the phenomenological optical potential is discussed . the predictions of the relativistic green s function model are compared with the results of different descriptions of final - state interactions .
| 113
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1306.2220
|
analyses of primitive meteorites and cometary samples have shown that the solar nebula must have experienced a phase of large - scale outward transport of small refractory grains as well as homogenization of initially spatially heterogeneous short - lived isotopes . the stable oxygen isotopes , however , were able to remain spatially heterogenous at the @xmath0 6% level . one promising mechanism for achieving these disparate goals is the mixing and transport associated with a marginally gravitationally unstable ( mgu ) disk , a likely cause of fu orionis events in young low - mass stars . several new sets of mgu models are presented that explore mixing and transport in disks with varied masses ( 0.016 to 0.13 @xmath1 ) around stars with varied masses ( 0.1 to 1 @xmath1 ) and varied initial @xmath2 stability minima ( 1.8 to 3.1 ) . the results show that mgu disks are able to rapidly ( within @xmath3 yr ) achieve large - scale transport and homogenization of initially spatially heterogeneous distributions of disk grains or gas . in addition , the models show that while single - shot injection heterogeneity is reduced to a relatively low level ( @xmath0 1% ) , as required for early solar system chronometry , continuous injection of the sort associated with the generation of stable oxygen isotope fractionations by uv photolysis leads to a sustained , relatively high level ( @xmath0 10% ) of heterogeneity , in agreement with the oxygen isotope data . these models support the suggestion that the protosun may have experienced at least one fu orionis - like outburst , which produced several of the signatures left behind in primitive chondrites and comets .
| 285
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1701.03589
|
we calculate the josephson current between two one - dimensional ( 1d ) nanowires oriented along @xmath0 with proximity induced @xmath1-wave superconducting pairing and separated by a narrow dielectric barrier in the presence of both rashba spin - orbit interaction ( soi ) characterized by strength @xmath2 and zeeman fields ( @xmath3 along @xmath4 and @xmath5 in the @xmath6 plane ) . we formulate a general method for computing the andreev bound states energy which allows us to obtain analytical expressions for the energy of these states in several asymptotic cases . we find that in the absence of the magnetic fields the energy gap between the andreev bound states decreases with increasing rashba soi constant leading eventually to touching of the levels . in the absence of rashba soi , the andreev bound states depend on the magnetic fields and display oscillatory behavior with orientational angle of b leading to magneto - josephson effect . we also present analytic expressions for the dc josephson current charting out their dependence on @xmath5 , @xmath3 , and @xmath2 . we demonstrate the existence of finite spin - josephson current in these junctions in the presence of external magnetic fields and provide analytic expressions for its dependence on @xmath2 , @xmath7 and @xmath3 . finally , we study the ac josephson effect in the presence of the soi ( for @xmath8 ) and an external radiation and show that the width of the resulting shapiro steps in such a system can be tuned by varying @xmath2 . we discuss experiments which can test our theoretical results .
| 265
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hep-ex9506008
|
we present three searches for new particles at cdf . first , using 70 pb@xmath0 of data we search the dijet mass spectrum for resonances . there is an upward fluctuation near 550 gev / c@xmath1 ( 2.6@xmath2 ) with an angular distribution that is adequately described by either qcd alone or qcd plus 5% signal . there is insufficient evidence to claim a signal , but we set the most stringent mass limits on the hadronic decays of axigluons , excited quarks , technirhos , w@xmath3 , z@xmath3 , and e6 diquarks . second , using 19 pb@xmath0 of data we search the b - tagged dijet mass spectrum for @xmath4 resonances . again , an upward fluctuation near 600 gev / c@xmath1 ( 2 @xmath2 ) is not significant enough to claim a signal , so we set the first mass limits on topcolor bosons . finally , using 67 pb@xmath0 of data we search the top quark sample for @xmath5 resonances like a topcolor @xmath6 . other than an insignificant shoulder of 6 events on a background of 2.4 in the mass region 475 - 550 gev / c@xmath1 , there is no evidence for new particle production . mass limits , currently in progress , should be sensitive to a topcolor z@xmath3 near 600 gev / c@xmath1 . in all three searches there is insufficient evidence to claim new particle production , yet there is an exciting possibility that the upward fluctuations are the first signs of new physics beyond the standard model . fermilab - conf-95/152-e + cdf / pub / exotic / public/3192 + + * search for new particles decaying to dijets , + @xmath4 , and @xmath5 at cdf + * _ fermilab ms 318 + batavia , il 60510 + _
| 300
|
astro-ph0609669
|
we review the theory and observations of star cluster disruption . the three main phases and corresponding typical timescales of cluster disruption are : _ i ) infant mortality _ ( @xmath0 yr ) , _ ii ) stellar evolution _ ( @xmath1 yr ) and _ iii ) tidal relaxation _ ( @xmath2 yr ) . during all three phases there are additional tidal external perturbations from the host galaxy . in this review we focus on the physics and observations of phase i and on population studies of phases ii & iii and external perturbations ( concentrating on cluster - gmc interactions ) . particular attention is given to the successes and short - comings of the lamers cluster disruption law , which has recently been shown to stand on a firm physical footing .
| 137
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1404.0246
|
ergodic homeomorphisms @xmath0 and @xmath1 of polish probability spaces @xmath2 and @xmath3 are _ evenly kakutani equivalent _ if there is an orbit equivalence @xmath4 between full measure subsets of @xmath2 and @xmath3 such that , for some @xmath5 of positive measure , @xmath6 restricts to a measurable isomorphism of the induced systems @xmath7 and @xmath8 . the study of even kakutani equivalence dates back to the seventies , and it is well known that any two zero - entropy loosely bernoulli systems are evenly kakutani equivalent . but even kakutani equivalence is a purely measurable relation , while systems such as the morse minimal system are both measurable and topological . recently del junco , rudolph and weiss studied a new relation called _ nearly continuous kakutani equivalence_. a nearly continuous kakutani equivalence is an even kakutani equivalence where also @xmath9 and @xmath10 are invariant @xmath11 sets , @xmath12 is within measure zero of both open and closed , and @xmath6 is a homeomorphism from @xmath9 to @xmath10 . it is known that nearly continuous kakutani equivalence is strictly stronger than even kakutani equivalence , and nearly continuous kakutani equivalence is the natural strengthening of even kakutani equivalence to the _ nearly continuous _ category the category where maps are continuous after sets of measure zero are removed . in this paper we show that the morse minimal substitution system is nearly continuously kakutani equivalent to the binary odometer .
| 241
|
1608.08525
|
we used the magneto - dipole radiation mechanism for the braking of radio pulsars to calculate the new values of magnetic inductions at the surfaces of neutron stars . for this aim we estimated the angles @xmath0 between the rotation axis and the magnetic moment of the neutron star for 376 radio pulsars using three different methods . it was shown that there was the predominance of small inclinations of the magnetic axes . using the obtained values of the angle @xmath0 we calculated the equatorial magnetic inductions for pulsars considered . these inductions are several times higher as a rule than corresponding values in the known catalogs . * keywords * magnetic fields ; methods : data analysis ; methods : statistical ; _ ( stars : ) _ pulsars : general
| 133
|
0712.3111
|
the scattering processes of exotic atoms in excited states from hydrogen such as elastic scattering , stark transitions and coulomb de - excitation are studied within a close coupling approach . the vacuum polarization and the strong interaction shifts of @xmath0-states ( in case of hadronic atoms ) are taken into account . the differential and integral cross sections of the above processes are calculated to use them as the input in cascade calculations . the effect of closed channels on the scattering processes is investigated . * scattering processes of excited exotic atoms : close - coupling approach * + _ institute of nuclear physics , moscow state university , 119992 moscow , russia@xmath1 institution1 _
| 117
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astro-ph9807307
|
doppler measurements of the m4 dwarf star , gliese 876 , taken at both lick and keck observatory reveal periodic , keplerian velocity variations with a period of 61 days . the orbital fit implies that the companion has a mass of , @xmath0 = 2.1 m@xmath1 , an orbital eccentricity of , @xmath2 = 0.27@xmath30.03 , and a semimajor axis of , @xmath4 = 0.21 au . the planet is the first found around an m dwarf , and was drawn from a survey of 24 such stars at lick observatory . it is the closest extrasolar planet yet found , providing opportunities for follow up detection . the presence of a giant planet on a non - circular orbit , 0.2 au from a 1/3 m@xmath5 star , presents a challenge to planet formation theory . this planet detection around an m dwarf suggests that giant planets are numerous in the galaxy .
| 155
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1404.0153
|
the aim of this paper is to define a chain level refinement of the batalin - vilkovisky ( bv ) algebra structure on homology of the free loop space of a closed @xmath0-manifold . namely , we propose a new chain model of the free loop space , and define an action of a certain chain model of the framed little disks operad on it , recovering the original bv structure on homology level . we also compare this structure to a solution of deligne s conjecture for hochschild cochain complexes of differential graded algebras . to define the chain model of the loop space , we introduce a notion of de rham chains , which is a hybrid of singular chains and differential forms .
| 126
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astro-ph0503210
|
the gravitational waves generated during supermassive black hole ( smbh ) coalescence are prime candidates for detection by the satellite lisa . we use the extended press - schechter formalism combined with empirically motivated estimates for the smbh dark matter halo mass relation and smbh occupation fraction to estimate the maximum coalescence rate for major smbh mergers . assuming efficient binary coalescence , and guided by the lowest nuclear black hole mass inferred in local galactic bulges and nearby low - luminosity active galactic nuclei ( @xmath0 m@xmath1 ) we predict approximately 15 detections per year at a signal to noise greater than five , in each of the inspiral and ringdown phases . rare coalescences between smbhs having masses in excess of @xmath2 m@xmath1 will be more readily detected via gravitational waves from the ringdown phase . [ firstpage ] black hole physics , cosmology : theory , gravitational waves
| 151
|
0802.2528
|
in the @xmath0-@xmath1vc problem , we are given an undirected graph @xmath2 with edge costs and an integer @xmath0 ; the goal is to find a minimum - cost 2-vertex - connected subgraph of @xmath2 containing at least @xmath0 vertices . a slightly more general version is obtained if the input also specifies a subset @xmath3 of _ terminals _ and the goal is to find a subgraph containing at least @xmath0 terminals . closely related to the @xmath0-@xmath1vc problem , and in fact a special case of it , is the @xmath0-@xmath1ec problem , in which the goal is to find a minimum - cost 2-edge - connected subgraph containing @xmath0 vertices . the @xmath0-@xmath1ec problem was introduced by lau _ et al . _ @xcite , who also gave a poly - logarithmic approximation for it . no previous approximation algorithm was known for the more general @xmath0-@xmath1vc problem . we describe an @xmath4 approximation for the @xmath0-@xmath1vc problem .
| 162
|
0803.3627
|
the notion that microparsec - scale black holes can be used to probe gigaparsec - scale physics may seem counterintuitive , at first . yet , the gravitational observatory _ lisa _ will detect cosmologically - distant coalescing pairs of massive black holes , accurately measure their luminosity distance and help identify an electromagnetic counterpart or a host galaxy . a wide variety of new black hole studies and a gravitational version of hubble s diagram become possible if host galaxies are successfully identified . furthermore , if dark energy is a manifestation of large - scale modified gravity , deviations from general relativistic expectations could become apparent in a gravitational signal propagated over cosmological scales , especially when compared to the electromagnetic signal from a same source . finally , since inspirals of white dwarfs into massive black holes at cosmological distances may permit pre - merger localizations , we suggest that careful monitoring of these events and any associated electromagnetic counterpart could lead to high - precision cosmological measurements with _ lisa_.
| 174
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1005.0916
|
sdssj094857.3 + 002225 is a very radio - loud narrow - line seyfert 1 ( nls1 ) galaxy . here , we report our discovery of the intranight optical variability ( inov ) of this galaxy through the optical monitoring in the _ b _ and _ r _ bands that covered seven nights in 2009 . violent rapid variability in the optical bands was identified in this rl - nls1 for the first time , and the amplitudes of the inov reaches 0.5 mag in both the _ b _ and _ r _ bands on the timescale of several hours . the detection of the inov provides a piece of strong evidence supporting the fact that the object carries a relativistic jet with a small viewing angle , which confirms the conclusion drawn from the previous multi - wavelength studies .
| 143
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1405.1149
|
we propose using a single magneto - dielectric microsphere as a device for enhancing the transverse faraday effect at multiple wavelengths at the same time . although the diameter of the sphere can be @xmath0 @xmath1 m , the numerically predicted strength of its magneto - optical ( mo ) response can be an order of magnitude stronger than in mo devices based on thick magnetic plates . the mo response of a microsphere is also comparable with that of subwavelength magneto - dielectric gratings which , however , operate at a single wavelength and occupy a large area . in contrast to gratings and thick plates , the compact size of the microsphere and its capability to support spin - wave excitations make it suitable for applications in nanophotonics , imaging systems , and magnonics .
| 137
|
1610.00305
|
in the population synthesis simulations of pop iii stars , many bh ( black hole)-bh binaries with merger time less than the age of the universe @xmath0 are formed , while ns ( neutron star)-bh binaries are not . the reason is that pop iii stars have no metal so that no mass loss is expected . then , in the final supernova explosion to ns , much mass is lost so that the semi major axis becomes too large for pop iii ns - bh binaries to merge within @xmath1 . however it is almost established that the kick velocity of the order of @xmath2 exists for ns from the observation of the proper motion of the pulsar . therefore , the semi major axis of the half of ns - bh binaries can be smaller than that of the previous argument for pop iii ns - bh binaries to decrease the merging time . we perform population synthesis monte carlo simulations of pop iii ns - bh binaries including the kick of ns and find that the event rate of pop iii ns - bh merger rate is @xmath3 . this suggests that there is a good chance of the detection of pop iii ns - bh mergers in o2 of advanced ligo and advanced virgo from this autumn .
| 222
|
0905.0145
|
we present far - ultraviolet photometry obtained with the _ hubble space telescope _ of the low - mass x - ray binary 4u 0513 - 40 in the globular cluster ngc 1851 . our observations reveal a clear , roughly sinusoidal periodic signal with @xmath0 min and amplitude 3%-10% . the signal appears fully coherent and can be modelled as a simple reprocessing effect associated with the changing projected area presented by the irradiated face of a white dwarf donor star in the system . all of these properties suggest that the signal we have detected is orbital in nature , thus confirming 4u 0513 - 40 as an ultracompact x - ray binary ( ucxb ) . all four confirmed ucxbs in globular clusters have orbital periods below 30 minutes , whereas almost all ucxbs in the galactic field have orbital periods longer than this . this suggests that the dynamical formation processes dominate ucxb production in clusters , producing a different orbital period distribution than observed among field ucxbs . based on the likely system parameters , we show that 4u 0513 - 40 should be a strong gravitational wave source and may be detectable by lisa over the course of a multi - year mission .
| 210
|
1406.3502
|
suppose that a lattice gas of constant density , described by the symmetric simple exclusion process , is brought in contact with a target " : a spherical absorber of radius @xmath0 . employing the macroscopic fluctuation theory ( mft ) , we evaluate the probability @xmath1 that no gas particle hits the target until a long but finite time @xmath2 . we also find the most likely gas density history conditional on the non - hitting . the results depend on the dimension of space @xmath3 and on the rescaled parameter @xmath4 , where @xmath5 is the gas diffusivity . for small @xmath6 and @xmath7 , @xmath1 is determined by an exact stationary solution of the mft equations that we find . for large @xmath6 , and for any @xmath6 in one dimension , the relevant mft solutions are non - stationary . in this case @xmath8 scales differently with relevant parameters , and it also depends on whether the initial condition is random or deterministic . the latter effects also occur if the lattice gas is composed of non - interacting random walkers . finally , we extend the formalism to a whole class of diffusive gases of interacting particles .
| 203
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