The oklo data constrain the depth of the nuclear potential well to a small margin of error ,...

beginning with shlyakhter [ 1 ] in 1976 , oklo natural reactor data have been used by many authors [ 2 - 6 ] to put limits on the time variation of `` constants '' such as the fine structure constant and the strong coupling constant . as noted by damour and dyson [ 2 ] , such constraints generally refer to the value of the `` constants '' at the time of the reactor shut down , since most prior evidence is diminished by the reaction process . also , it can not be ruled out that two or more factors may change concurrently , and one may cancel the effect of the other on whatever we are able to calculate for comparison with experiment . in this work , we will use the constraints provided by the samarium-149 cross section to provide a self - consistent limit on the value of the uranium-238 decay constant at the time of reactor shutdown . this implies a limit on possible differences between the strong coupling constant at the time of reactor shutdown and today . pierronne and marquez [ 7,8 ] developed the complex eigenvalue method for calculating alpha - decay half - lives by matching the wavefunction of the alpha particle , and its derivative , across a boundary between a square well representing the nuclear interior and a coulomb potential representing the exterior of the nucleus outside the range of nuclear forces . chaffin , banks , gothard , and tuttle [ 9,10 ] have further developed this method into _ mathematica _ notebooks permitting easy calculation of relevant variations . experimental data on alpha particle scattering [ 11 - 14 ] have long been known to validate a cluster model in which an alpha particle moves in the average field provided by the rest of the nucleus . four - nucleon transfer reactions were observed on target nuclei that are the _ daughters _ of an alpha emitter . the comparison of reaction rates with the corresponding alpha - decay rates indicates the tendency for the four transferred particles to form a true alpha particle . the data give evid

We present a new method for calculating the decay constant at the time of reactor shutdown. This method is based on the samarium-149 cross section and is derived from the eigenvalue method for the uranium-238 decay constant. The results are presented in terms of the corresponding alpha particle scattering rate, which is a function of the number of nucleons transferred to the target nuclei.

the oklo data constrain the depth of the nuclear potential well to a small margin of error , determined by various unknowns , such as the reactor temperature . however , we show that even these small variations could allow the u-238 half - life to vary by more than one order of magnitude . physics department , bob jones university , greenville , sc 29614 keywords : radioactivity , oklo , cluster models , tunneling


We describe the braiding statistics of topological twist defects in abelian bosonic bilayer...

quasiparticles of the -fqh state live on the quotient lattice , where the -matrix is given in . when , the theory has the same anyon content as the kitaev toric code and the quotient lattice decomposes into as all quasiparticles can be uniquely be written as where and . when is odd , 2 is invertible in by and the transformation gives an isomorphism of the quotient lattice with inverse as mod . thus where each quasiparticle has a unique decomposition where and are the charge and bilayer / spin vectors . the fqh quasiparticle -symbols are chosen to be multilinear homomorphisms . ( i ) for toric code when . ( ii ) for -fqh states with odd . under this convention , -symbols can be chosen to be trivial one and the quasiparticle strings satisfy the crossing , bootstrap and bending rules . {rxy1.pdf}}}=}}r^{{ a}{ b}}=}}r^{{ a}{ b}}r^{{ b}{ a}},}}=}},}}=}}=}}\ ] ] the double loop operator carries an anyon twice around a twist defect as shown in fig . we have the relations ( i ) , ( ii ) and ( iii ) , where is the eigenvalue for the bare defect ( ) . $ ] satisfies ( i iii ) , where the constant is fixed by requiring that , so that is well - defined on the anyon lattice . the result is eq .. basis transformation between different fusion trees with defect channels can be generated by a consistent set of fundamental -moves . in table [ tab : fsymbols ] , we list all the -symbols for toric code and -fqh states . these -symbols are calculated by gluing the splitting states defined in figure [ fig : splittingstates ] by joining quasiparticle strings . here we illustrate the calculation of the symbol that relates in -fqh states for odd . -matrix _{ a}^{ b}$ ] . the sum over wilson loops ( blue ) is restricted to an arbitrary set of quasiparticles with distinct spin components as ( see figure [ fig : doubleloop ] ) . the operator flips the branch cut configuration from joining to connecting .,width=624 ] the splitting state for is represented by the first diagram and that for is at

We study the -symbols for toric code and -fqh states with odd. We find that the eigenvalue for the bare defect is fixed by requiring that, so that is well - defined on the anyon lattice.

we describe the braiding statistics of topological twist defects in abelian bosonic bilayer fractional quantum hall ( fqh ) states , which reduce to the toric code when . twist defects carry non - abelian fractional majorana - like characteristics . we propose local statistical measurements that distinguish the fractional charge , or species , of a defect - quasiparticle composite . degenerate ground states and basis transformations of a multi - defect system are characterized by a consistent se


The bethe - salpeter equation in unitarized chiral perturbation theory is usually solved with the...

in the past two decades , a lot of progress has been made in applying nonperturbative approaches based on principles of effective field theories to understand low - energy strong interaction phenomena . one prominent example is the combination of chiral lagrangians with unitarization techniques , i.e. , the so - called unitarized chiral perturbation theory ( uchpt ) . compared to other phenomenological methods , uchpt has a more transparent link to the theory underlying the strong interactions , quantum chromodynamics ( qcd ) , and , as a result , is in principle improvable in a systematic manner . over the years , it has provided new insights into the nature of various hadrons , from the well - established hadrons , such as the or the , to those of the newly observed particles , such as the or the . at the heart of uchpt are the interaction kernels provided by chiral lagrangians , which are constrained by qcd and its approximate symmetries , such as chiral symmetry and heavy quark spin / flavor symmetry and their breaking pattern . exact two - body ( -channel ) unitarity can be implemented in different ways and a widely adopted approach is the bethe - salpeter ( bs ) approach . it is well known that the bs approach provides exact unitarity but loses crossing symmetry , compared to conventional chiral perturbation theory . to simplify the solution of the bethe - salpeter equation , the so - called on - shell approximation is often adopted . it assumes that the interaction kernel can be put on the mass shell with the argument that the off - shell terms can be absorbed by the available coupling constants and physical hadron masses . a vast amount of applications has shown that such an approximation works very well . nevertheless , from a formal point of view , one may prefer to take into account the full off - shell effects to have an order - to - order correspondence with the underlying results of chiral perturbation theory . such off - shell effects have been studie

We present a new approach to the bethe - salpeter equation for the interaction kernel of chiral lagrangians. It is shown that the off - shell terms can be absorbed by the available coupling constants and physical hadron masses. This approach is based on the theory of quantum chromodynamics ( qcd ), which is a well - known method for understanding low - energy strong interactions.

the bethe - salpeter equation in unitarized chiral perturbation theory is usually solved with the so - called on - shell approximation . the underlying argument is that the off - shell effects can be absorbed by the corresponding coupling constants and physical masses , which has been corroborated by the success of unitarized chiral perturbation theory in describing a variety of physical phenomena . such an approximation needs to be scrutinized when applied to study the light - quark mass evolut


We investigate the impact finite simulation box size has on the structural and kinematic properties...

over the last twenty years , the cosmological n - body simulation has come to be firmly established as the preeminent tool for theoretical studies of the formation and evolution of structure in the universe ( see for a relatively recent review ) . whereas early studies explored the gross features of different cosmological models and led to the emergence of the cold dark matter ( cdm ) paradigm , the most recent generation of simulations are being used to provide detailed predictions of the cdm model and in particular its cdm variant . these include the behaviour of cdm halo mass profiles on scales that can be directly compared with observations ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) and sophisticated semi - analytical models of galaxy formation built upon merger trees harvested from high resolution simulations ( c.f . the millennium simulation described in * ? ? ? the n - body approach is not without its limitations , however , and given its significance , it is of fundamental importance to understand what these limitations are and how they affect the interpretation of the results of simulations . such considerations generally lead to `` convergence '' studies that seek to quantify the degree to which the results of a simulation are affected by choices made in its setting up and running . for example , both and demonstrated that their results on the form of cdm halo mass profiles were not compromised by force resolution ( or `` softening '' ) as well as starting redshift and particle number . the recent study of established a set of convergence criteria ( reaffirmed by * ? ? ? * ) that determine the radial range over which the circular velocity profile of a simulated cdm halo is reliable to better than accuracy , for a number of simulation parameters including softening , time integration accuracy , and particle number ( see also * ? ? ? * ; * ? ? ? more generally , investigated how properties such as the correlation function , mass function and central densitie

We present a set of convergence criteria for the radial range over which the circular velocity profile of a simulated cold dark matter ( cdm ) halo is reliable to better than accuracy, for a number of simulation parameters including softening, time integration accuracy and particle number. These criteria are based on the n - body approach, and are derived from the results of two recent studies. The first study found that the ccd halon mass profiles were not compromised by force resolution ( or a softenING ) as well.

we investigate the impact finite simulation box size has on the structural and kinematic properties of cold dark matter haloes forming in cosmological simulations . our approach involves generating a single realisation of the initial power spectrum of density perturbations and studying how truncation of this power spectrum on scales larger than affects the structure of dark matter haloes at . in particular , we have examined the cases of with ( i.e. no truncation) and . in common with previous s


We consider the statistics of the number of nodal domains aka nodal counts for eigenfunctions of...

we consider real square - integrable eigenfunctions of the stationary schrdinger equation for a massive point particle on an -dimensional smooth connected riemannian manifold with local coordinates . here , is the laplace - beltrami operator on , is a potential , and is an energy eigenvalue . we have set the value of the physical constant of planck s constant squared over twice the mass of the particle equal to one by appropriate choice of units . + we will allow that has a boundary and will impose boundary conditions on such that the schrdinger operator defined in ( [ schrod ] ) is self - adjoint ( e.g. dirichlet or neumann boundary conditions ) . + we consider only non - negative potentials for which the _ classically allowed region _ is compact and connected . this ensures a discrete and non - negative energy spectrum . if ( free motion ) the condition implies that the manifold is compact . we arrange the spectrum in ascending order as and denote by the eigenfunction corresponding to . for a given eigenfunction the nodal set consists of all points on the manifold where the eigenfunction vanishes . a nodal domain of is a maximally connected region where the sign of does not change . the characterisation of eigenfunctions in terms of their nodal set has a history which is more than 200 years old with the first systematic treatment by chladni who visualised the vibration modes of plates with sand that accumulates at the nodal set . among other things he also counted the number of different nodal domains for each vibration mode and used these number to characterise the modes for a given shape . the number of nodal domains of eigenfunctions or _ nodal counts _ will also be the subject of the present contribution . for the wave function we denote the nodal count by . the collection of all nodal counts forms the _ nodal sequence _ ( for systems with degenerate eigenvalues this definition of the nodal sequence is incomplete ) . + in one dimension sturm s oscillation theo

We consider real square - integrable eigenfunctions of the stationary schrdinger equation for a massive point particle on an -dimensional smooth connected riemannian manifold with local coordinates. We consider only non - negative potentials for which the classically allowed region is compact and connected. This ensures a discrete and non -negative energy spectrum. For, we denote the nodal count by.

we consider the statistics of the number of nodal domains aka nodal counts for eigenfunctions of separable wave equations in arbitrary dimension . we give an explicit expression for the limiting distribution of normalised nodal counts and analyse some of its universal properties . our results are illustrated by detailed discussion of simple examples and numerical nodal count distributions .


We present the results on period search and modeling of the cool dav star kuv 02464 + 3239

since arlo landolt s ( 1968 ) discovery of the first dav we have learned much about pulsating white dwarfs . they are otherwise normal white dwarf stars , and they represent the final stage of about 98% of the stars ( see the recent review of and references therein ) , so it is a key issue to gain insight into their interiors . while white dwarfs are relatively simple to model , some observed phenomena still challenge theory . one unsolved mystery is the variability of the pulsational modes amplitudes and frequencies of pnnv , cool dbv and cool dav stars . while we can find very stable modes in certain white dwarfs which can be used to measure evolutionary effects ( cooling and/or contraction , e.g. hot davs g117-b15a and r548 ` the most stable optical clocks known ' : mukadam , kepler & winget 2001 and references therein ) , in some cases short - term variabilities make it difficult to determine even the pulsational modes . an example for this latter is the case of pg 1115 + 158 ( dbv ) with its remarkably unstable amplitude spectra . in some cases we encounter strange , sudden , short - term variations in the pulsational behaviours of stars : for example the ` sforzando ' effect observed in the dbv star gd 358 in 1996 , where the nonlinear light curve of the star changed into a high amplitude , remarkably sinusoidal one for a short period of time ( , ) . in the case of pg 1456 + 103 its luminosity variations almost disappeared just before the whole earth telescope ( wet , ) run started on the star . the frequency and amplitude variations of multiplet components ( mostly for high modes ) observed in gd 358 are further examples for short - term variations . possible explanations for these observed phenomena could be non - linear mode coupling , convection / pulsation interactions , mode excitation , and beating of different pulsation modes such as unresolved rotational splitting . to find the right explanation(s ) for a certain case is a great challenge . a crucial

We present a new study of the pulsational modes in a white dwarf star, pg 1115 + 158 ( dbv ). We find that the amplitude and frequency variations of multiplet components are not consistent with the observed fluctuations. The spectral properties of these components are also investigated.

we present the results on period search and modeling of the cool dav star kuv 02464 + 3239 . our observations resolved the multiperiodic pulsational behaviour of the star . in agreement with its position near the red edge of the dav instability strip , it shows large amplitude , long period pulsation modes , and has a strongly non - sinusoidal light curve . we determined 6 frequencies as normal modes and revealed remarkable short - term amplitude variations . a rigorous test was performed for th


We present the prototype telescope for the next generation transit survey , which was built in the...

the next generation transit survey ( ngts ) is a new wide - field photometric survey for transiting exoplanets recently commissioned at eso paranal , chile . the motivation behind ngts is to understand planetary formation and evolution , as well as determining atmospheric and bulk compositions of neptune and super - earth sized exoplanets . this can only be achieved by characterising , both photometrically and spectroscopically , a large sample of such objects . the _ kepler _ survey has shown there to be an abundance of neptune sized objects in their field . however , while the results from _ kepler _ are important in terms of statistics , the mean brightness of host stars of small planets observed by _ kepler _ is too faint for efficient spectroscopic follow up from the ground . the ngts project ( wheatley et al . , in prep , , ) was designed to detect this population of neptune - sized transiting exoplanets around bright ( v ) k and early m - type stars accessible to the eso telescopes . showed that systematic ( red ) noise is non - negligible when searching for transiting exoplanets and hence limits the detection efficiency of most ground - based surveys . initial predictions of transiting planet detection rates considered uncorrelated ( white ) noise only , overlooking the effects of red noise . pont et al . suggest that this may explain the inconsistency between transiting exoplanet detection rates compared to initial predictions . investigated the effects of systematic noise on the detection efficiency of superwasp and concluded that the survey suffered significantly from a systematic noise component in the data . the noise in superwasp was determined to be a combination of both red and white ( pink ) noise . the level of systematic noise was reduced using the sysrem detrending algorithm , but was not removed completely . as a result superwasp was forced to acquire more transits of each planet to increase the signal - to - noise ratio of their detections . in

The next generation transit survey ( ngts ) is a new wide - field photometric survey for transiting exoplanets recently commissioned at eso paranal, chile. The aim of this project is to understand planetary formation and evolution, as well as determining atmospheric and bulk compositions of neptune and super - earth sized exoplanetarys. However, the results from _ kepler _ survey are important in terms of statistics, and hence limit the detection efficiency of most ground -.

we present the prototype telescope for the next generation transit survey , which was built in the uk in 2008/09 and tested on la palma in the canary islands in 2010 . the goals for the prototype system were severalfold : to determine the level of systematic noise in an ngts - like system ; demonstrate that we can perform photometry at the ( sub ) millimagnitude level on transit timescales across a wide field ; show that it is possible to detect transiting super - earth and neptune - sized exopl


We report new experimental studies to understand the physics of phonon sensors which utilize...

quasiparticle transport dynamics have been studied in the lab by many groups using different materials , fabrication processes , and readout schemes . quasiparticle transport in al films plays an important role in the design specifications of cryogenic dark matter search ( cdms ) detectors . these detectors utilize photolithographically patterned films of sputtered al and w on both sides of high - purity , kg - scale , ge and si crystals . the superconducting al and w films perform two roles simultaneously : they absorb phonon energy and they serve as ionization collection electrodes . when a particle interacts with a cdms detector , electron - hole pairs and phonons are created . under typical operating conditions , a v / cm bias is used to drift the e-/h+ pairs through the bulk of the crystal so charge can be collected at the detector surfaces . at the same time , the athermal phonons produced by the event make their way to the detector surfaces where they can be absorbed in the al film by breaking cooper pairs which create quasiparticles . ideally , the quasiparticles diffuse randomly in the al until they get trapped in the overlap region between the al and w films , where the superconducting energy gap is smaller than in the al film alone . this trapped energy gets absorbed by an attached w - tes , adding heat and providing the detector s phonon signal for that event . we call these phonon sensors quasiparticle - trap - assisted - electrothermal - feedback transition - edge - sensors ( qets ) . the quasiparticle ( qp ) trapping length in cdms al films impacts overall detector energy performance . here we present results from a detailed study of energy collection and qp propagation in al films coupled to w - tess and describe an innovative model that explains qet pulse shapes and overall performance , and provides a way to measure qp trapping lengths in thin films and the energy transport efficiency from the qp energy to the tes electron system . our measurements

We present results from a detailed study of energy collection and qp propagation in al films coupled to w - tess. The model is based on an efficient qet pulse shape that describes the energy transport efficiency from the qP energy to the tes electron system. We describe a new model that explains the asymmetric qpetractors and their effects on the energy transfer between the w and tes electrodes, and provides a way to measure the energy distribution of the ph - phase transitions in thin films.

we report new experimental studies to understand the physics of phonon sensors which utilize quasiparticle diffusion in thin aluminum films into tungsten transition - edge - sensors ( tess ) operated at 35 mk . we show that basic tes physics and a simple physical model of the overlap region between the w and al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x - rays absorbed in the al films . we further estimate quasiparticle loss in al film


We report heating rate measurements in a microfabricated gold - on - sapphire surface electrode ion...

trapped ions provide a promising candidate to pursue quantum information processing . successful implementations of basic quantum protocols as well as the creation of entangled states support this view . a promising route to scalability of ion - trap based quantum information processing was proposed in which segmented trap electrodes allow splitting , shuttling , and recombination of ion crystals . to overcome the difficulties of assembling three - dimensional trap structures and simplify fabrication , several groups are developing planar ( surface ) ion traps where all electrodes lie within one plane and can be constructed using standard microfabrication methods . in particular , recently the nist group successfully transported ions through junctions in such planar traps . despite the recent progress , there are still a number of unresolved difficulties with planar traps . in the effort to develop this technology , one strives for miniaturization in order to easily achieve the high trap frequencies required for fast splitting of ion crystals , and to increase coupling rates in approaches where trapped ions are coupled to or via solid state elements . thus , planar traps with ion - surface separations of less than 100 m are pursued . however , the observed ion heating rates are more than 3 orders of magnitude higher than those expected from johnson noise considerations , imposing a major obstacle in developing this approach . this so - called `` anomalous '' heating in ion traps is usually discussed in terms of the `` patch potential '' model . the essential features of this model are that the electric field noise responsible for heating of the ion motion arises from a large number of randomly fluctuating sources and that the electric field of individual sources scales with source - ion separation as an electrical dipole field . these two features reproduce the observed scaling of the electric field noise with the separation , , between the ion and trap electrodes .

We present a new approach to the scalability of ion - trap based quantum information processing by using a planar ( surface ) ionic trap with ione separations of less than 100 m. This approach is based on the johnson noise model and is characterized by an electric field noise that scales with source - io separation as an electrical dipole field. The observed scaling of the electric field Noise in the trap is reproduced by the ionne - electrode separation, which is a large number of randomly fluctuating.

we report heating rate measurements in a microfabricated gold - on - sapphire surface electrode ion trap with trapping height of approximately 240 m . using the doppler recooling method , we characterize the trap heating rates over an extended region of the trap . the noise spectral density of the trap falls in the range of noise spectra reported in ion traps at room temperature . we find that during the first months of operation the heating rates increase by approximately one order of magnitude


In this study we analyze the dynamics of the contact list evolution of millions of users of the...

the structure and evolution of human interactions are generally characterized by heterogeneity in manifold ways and are influenced by correlations ranging from individual level to global scale . some of these emerging heterogeneities have been identified as the result of simple processes driven by microscopic rules . for example , preferential attachment has been shown to introduce degree heterogeneity and short path - ways into an evolving network structure . at the same time studies of action sequences such as communication actions in social networks have put into evidence further mechanisms responsible for inhomogeneities in network structure and dynamics . it has been shown in particular that correlated dynamics of individuals induce bursty temporal patterns of interactions . however , for the most , these studies draw their conclusions from observation of static network snapshots or from incomplete temporal sequences of interactions . only recently a number of datasets have been collected that contain time - stamped records of all topological actions , such as addition and deletion of edges between pairs of users . this development has opened the possibility to study directly the governing microscopic rules of network evolution in order to confirm previous hypothesis and to explore new mechanisms . in particular , the availability of time - stamped records of user registrations , edge additions and edge deletions , allows to explore in details the microscopic evolution of _ egocentric networks _ consisting of an individual user and their immediate friends or `` contacts '' . such datasets allow us to determine if the evolution of egocentric networks is incremental ( small constant changes ) or instead is characterized by sudden changes ( bursts ) . sudden changes in the egocentric network could be induced by changes in the ego s social status ( e.g. moving to a new place or starting a school ) but also by the adoption of new services which open possibilities fo

We present a new method for studying the evolution of egocentric networks in order to confirm previous hypothesis and explore new mechanisms. We use time - stamped records of user registrations, edge additions and deletions. This technique allows us to study the microscopic evolution of the network structure and dynamics.

in this study we analyze the dynamics of the contact list evolution of millions of users of the skype communication network . we find that egocentric networks evolve heterogeneously in time as events of edge additions and deletions of individuals are grouped in long bursty clusters , which are separated by long inactive periods . we classify users by their link creation dynamics and show that bursty peaks of contact additions are likely to appear shortly after user account creation . we also stu


M giants are among the longest - period pulsating stars which is why their studies were...

m giants are long - period variables requiring years of continuous observations for their study . much of our recent knowledge was gained from microlensing surveys of the magellanic cloud and the galactic bulge , such as macho , ogle and eros . while analysing photometric data of red giants in the macho survey of the lmc , found several sequences in the period - luminosity ( p - l ) plane , which were labelled as a , b , c , e and d , representing shorter to longer periods . subsequent studies have shown that these structures of the sequences is rich , with over a dozen features that are related to luminosity ( below or above the tip of the red giant branch - see , e.g. , ) and chemical composition ( carbon - rich vs. oxygen - rich , * ? ? ? * ) or might have a dependency on the wavelength range of the luminosity indicator . the most distinct parallel sequences a and b represent the radial overtone modes of semiregulars ( sr ) . these stars are numerous and most of them have multiple periods . the miras lie on sequence c , which corresponds to the fundamental mode . the power spectra of semiregulars that are observed for a large number of pulsation periods show modes with solar - like lorentzian envelopes . this suggests that stochastic excitation and damping take place . with decreasing luminosities the pulsations decrease in amplitude and become more difficult to detect . however , these also have shorter periods , making them good candidates for high - quality space photometry from _ corot _ and _ kepler_. in addition to the mentioned sequences of the srs and miras , there are two sequences in the p - l plane : sequence e and d representing the eclipsing binaries and the long secondary periods , respectively . the latter remains unexplained . although there is significant improvement in the understanding of m giant variability , there remain many question regarding the excitation and damping of the pulsations , and the expected crossover from mira - like to solar

We present a new study of the period - luminosity ( p - l ) plane of red giants in the macho survey of the lmc. The pulsation periods are measured using the _ corot _ and _ kepler _ telescopes. We find that the eclipsing binaries have a long - period, with a mean - time duration of. This is consistent with the observed pulses.

m giants are among the longest - period pulsating stars which is why their studies were traditionally restricted to analyses of low - precision visual observations , and more recently , accurate ground - based data . here we present an overview of m giant variability on a wide range of time - scales ( hours to years ) , based on analysis of thirteen quarters of _ kepler _ long - cadence observations ( one point per every 29.4 minutes ) , with a total time - span of over 1000 days . about two - t


Single - particle resonant - states in the continuum are determined by solving scattering states of...

in recent years , the physics of exotic nuclei attracts more attentions both experimentally and theoretically . due to the closeness of the fermi surface to the particle continuum in exotic nuclei the coupling between bound states and the particle continuum become important . the description of exotic nuclei has to explicitly include the coupling between bound states and the continuum . although there are several extensive theoretical studies of exotic nuclei using relativistic and non - relativistic microscopic methods , a rigorous treatment of the continuum for exotic nuclei is still under investigation . nuclei beyond the drip line are usually unbound and often exhibit resonances with a pronounced single - particle character , which are single - particle resonance states . the direct emission of charged particle from an unbound ground state has been observed in the three - body decay of o , which is closely linked with the energies and widths of resonant - states . in microscopic studies nuclear collective giant resonances are explained by the particle - hole excitations in a coherent way , where the particle continuum plays an important role . the contribution from the resonant states in the giant resonances has been studied in the so - called resonant random phase approximation in the non - relativistic approach by curutchet et . it was found that the contribution of the particle continuum is mainly from the single - particle resonances in the continuum . therefore , the exploration of single - particle resonant - states becomes very important in explaining the properties of ground states , dynamical processes of nuclei , excited nuclei , especially in understanding properties of nuclei far from the stable line . it is known that in most previous theoretical nuclear structure calculations , when the contribution from the continuum is performed the single - particle states in the continuum are usually treated by a discretization procedure with expanding the wave

We study the contribution of the continuum in a non - relativistic approach to the three - body decay of o, which is closely linked with the energy and widths of single - particle resonances. The contributions from the continuumal phase are studied in the so - called resonant random phase approximation by curutchet et. It is found that the contribution from the resonsant states in the continuumic wave is mainly from the single _ particle _ resonances in the amplitude of the corresponding resembl.

single - particle resonant - states in the continuum are determined by solving scattering states of the dirac equation with proper asymptotic conditions in the relativistic mean field theory ( rmf ) . the regular and irregular solutions of the dirac equation at a large radius where the nuclear potentials vanish are relativistic coulomb wave functions , which are calculated numerically . energies , widths and wave functions of single - particle resonance states in the continuum for sn are studied


The realistic equation of state of strongly interacting matter , that has been successfully applied...

one expects that the studies of relativistic heavy - ion collisions may bring us information about the properties of matter in the early universe ( at the time when its age was about 10 microseconds and its temperature was about 200 mev ) . in this paper we give an explicit example showing how such expectations may be realized in practice . our main point is that the theoretical analysis of the hadronic observables collected at rhic ( relativistic heavy ion collider at bnl ) pinned down the form of the equation of state ( eos ) of strongly interacting matter . the use of this eos in the friedmann equation allows us to determine the precise time evolution of the thermodynamic parameters in the early universe . until recently , the soft hadronic observables measured at rhic have been described with the help of the hydrodynamic models which incorporated the first - order phase transition between the quark - gluon plasma and hadronic matter . the main success of this approach was the correct reproduction of the hadron transverse - momentum spectra and the elliptic - flow coefficient . on the other hand , the hydrodynamic models using the first - order phase transition had severe problems with the reproduction of pionic correlation functions . the latter contain the information about the space - time dimensions of hadronic systems formed in the collisions . thus , the evident _ successes _ in the reproduction of the hadron _ momentum distributions _ were obscured by the _ failures _ connected with the analysis of the _ space - time dimensions _ of the produced system . the large part of those difficulties , known in the literature as the hbt puzzle , was removed by the use of the eos with the crossover phase transition . the crossover phase transition is not a genuine phase transition all thermodynamic parameters change smoothly as functions of the temperature , however , such changes may be quite sudden in a narrow temperature range . the crossover phase transition _ wi

We present a new method for the analysis of the hadronic observables collected at rhic ( relativistic heavy ion collider at bnl ). The method is based on the first - order phase transition between the quark - gluon plasma and hadron matter. It is shown that the eos of strongly interacting matter can be used to determine the precise time evolution of the thermodynamic parameters in the early universe.

the realistic equation of state of strongly interacting matter , that has been successfully applied in the recent hydrodynamic studies of hadron production in relativistic heavy - ion collisions at rhic , is used in the friedmann equation to determine the precise time evolution of thermodynamic parameters in the early universe . a comparison with the results obtained with simple ideal - gas equations of state is made . the realistic equation of state describes a crossover rather than the first -


We investigate quantum photovoltaic effect in double quantum dots by applying nonequilibrium...

as fossil - fuels , the current main energy supplies in our modern society , get scarcer and more expensive , renewable energies become increasingly important and desirable . to meet this demand , the solar energy , a significant green energy source , attracts a broad spectrum of attention from both industrial applications and fundamental researches . in particular , the photovoltaic effect , firstly discovered by e. becquerel in , is a potential promising technology for light harvesting , which converts the inexhaustible sunlight to electricity for performing useful work . great efforts have been made to design efficient semiconductor - based solar cells . however , the obtained efficiency is still too low to meet human daily needs . the main reason comes from that the excess excitation energy of the electron - hole pair above the energy gap will be wasted through thermal phonon emission . by adding multiple impurity levels , m. wolf expected the photovoltaic enhancement for the low energy spectrum collection . while shockley and queisser suggested that the included impurity would also strengthen the recombination process correspondingly , resulting in no improvement of the photovoltaic current . moreover , various other proposals have been raised to enhance the solar conversion efficiency . recently , quantum dot ( qd ) emerges as an alternative candidate to fabricate solar cells , due to the ability of enhancing the photon harvesting via the multi - level structure . the novel feature of qd is that by adjusting the dot size , the energy scale of the excitation gap can be tuned across a wide regime , which extends the absorption spectrum down to the infrared range and makes qd competitive in designing multi - junction solar cells . particularly , the influence of the quantum coherence on improving photovoltaic efficiency has been addressed by m. o. scully et . al . they studied the photovoltaic cells as quantum heat engine modeled by electronic level systems reson

We study the photovoltaic effect of quantum dot ( qd ) in a multi - level structure. By adjusting the dot size, the energy scale of the excitation gap can be tuned across a wide regime, which extends the absorption spectrum down to the infrared range and makes qD competitive in designing multi - junction solar cells.

we investigate quantum photovoltaic effect in double quantum dots by applying nonequilibrium quantum master equation . the drastic suppression of the photovoltaic current is observed near the open circuit voltage , which leads to the large filling factor . we find that there always exists an optimal inter - dot tunneling that significantly enhances the photovoltaic current . the maximal output power will also be obtained around the optimal inter - dot tunneling . moreover , the open circuit volt


We consider a generalized discrete model and demonstrate that it can support exact moving kink...

solitary waves play important role in a great variety of applications because they are robust against perturbations and they can transport various physical quantities such as mass , energy , momentum , electrical charge , and also information . many popular continuum nonlinear equations support traveling solutions , but for their discrete analogs the existence of traveling solutions was not systematically studied until recently . previously , only a few integrable lattices were known to support moving solitons , e.g. , the toda lattice and the ablowitz - ladik lattice , the former being the discrete version of the kdv equation and the latter of the nonlinear schrdinger ( nls ) equation . while integrable lattices of other key continuum models are also available , these integrable situations are still rather exceptional and typically not directly relevant to experimental settings . on the other hand , recently several wide classes of discrete models supporting translationally invariant ( ti ) _ static or stationary _ solutions have been discovered and investigated for the discrete klein - gordon equation and the discrete nls equation . static solitary waves in such lattices possess the translational goldstone mode , which means that the solitary waves moving with _ vanishing _ velocity can be regarded as the exact solutions to these discrete equations ( although there are issues for finite but small velocities as explained e.g. , in ) . moving solutions propagating along a lattice at _ finite _ velocity have also been found analytically in and with the help of specially tuned numerical approaches in . traveling bright solitons in the nls lattice model with saturable nonlinearity are also very interesting . for this model the existence of soliton frequencies with vanishing peierls - nabarro energy barrier was demonstrated . it was shown that for the specific frequencies the static version of the model equation coincides with that of the integrable ablowitz - ladik equ

We study the existence of static solitary waves in the integrable schrdinger ( nls ) lattice model with vanishing peierls and nabarro energy barrier. For the specific frequencies the static version of the model equation coincides with that of the integrating ablowitz - ladik equ.

we consider a generalized discrete model and demonstrate that it can support exact moving kink solutions in the form of tanh with an arbitrarily large velocity . the constructed exact moving solutions are dependent on the specific value of the propagation velocity . we demonstrate that in this class of models , given a specific velocity , the problem of finding the exact moving solution is integrable . namely , this problem originally expressed as a three - point map can be reduced to a two - po


Lorentz invariance violation ( liv ) may be a good observational window on quantum gravity physics

postulating various symmetries in physics is largely justified by the quest for unified theories which rely on mathematical symmetries and on invariance of the fundamental laws . in the far past , the early universe was dominated by a dynamical symmetry evoluting to the complex diversity of broken symmetries . in the history of the universe the unique theory of space and time was characterized by plank scales : cm , and . later , the emergence of new phenomena on hierarchical levels lead to our present world composed on one side of galaxies of stars and on small scales of atoms , molecules and life . at present there is no consensus on the correct approach to the unification of small and large - scale physics : the nature of the small - scale of the space - time could be derived from the idea of `` fuzziness '' ( following to the heisenberg uncertainty principle ) or quantum foam discussed by , or , or sharply defined set of discrete points . this `` lumpiness '' or `` discreteness '' may affect photon propagation in the vacuum resulting in propagation anomalies . in consequence , the speed of light would differ with energy when photons travel through large distances . the searches for a physical theory uniformly valid in large ( strong field gravity , high energies , cosmology ) and small scales ( atoms , nuclei , elementary particles ) need empirical tests across these scales . the quickly developing domain of studies with astronomical observations of distant sources may shed new light on the subject . the purpose of this paper is purely experimental and no critical discussion about various theoretical approaches will be presented here , as it may be found in e.g. ( * ? ? ? * and references therein ) . the formalism in use will be limited to the one adopted in the time - of - flight studies with unpolarized photons from distant astrophysical sources . these constraints are usually translated into quantum gravity scale limits in the frame of considered models . in

We present a new approach to the unification of small and large - scale physics in the context of time - of - flight studies with unpolarized photons from distant astrophysical sources. This approach is based on the theory of fuzziness ( following to the heisenberg uncertainty principle ) or quantum foam, which is discussed by, or, sharply defined set of discrete points. The method is applied to the time, of, flight study with un Polarized photones from distant sources, and the results are presented.

lorentz invariance violation ( liv ) may be a good observational window on quantum gravity physics . within last few years , all major gamma - ray experiments have published results from the search for liv with variable astrophysical sources : gamma - ray bursts with detectors on - board satellites and active galactic nuclei with ground - based experiments . in this paper , the recent time - of - flight studies with unpolarized photons published from the space and ground based observations are r


In the past decades , weak convergence theory for stochastic processes has become a standard tool...

the hoffman jrgensen weak convergence theory in the space of bounded functions is a great success story in mathematical statistics [ ] . measurability assumptions are reduced to a minimum , no smoothness assumptions on the trajectories are needed , it applies in a vast variety of circumstances , and the topology of uniform convergence is fine enough so that , through the continuous mapping theorem and functional delta method , it implies weak convergence of a countless list of interesting statistical functionals . but precisely because of the strength of uniform convergence , there are circumstances where it does not hold . weak convergence can fail when the ( pointwise ) candidate limit process has discontinuous trajectories . think of empirical distributions based on residuals of some sort , that is , observations that are themselves approximations of some latent random variables . because of the measurement error in the ordinates , jump locations fail to be located exactly , and uniform convergence fails . the examples which interest us in this paper concern empirical copula processes , the empirical process based on residuals in a linear regression setting and empirical tail dependence function processes . a radical solution to the lack - of - convergence issue is to seek for another metric on an appropriate function space . the metric should be weak enough so that convergence does take place , but still strong enough to enable statistical applications . ideally , when the limit process has continuous trajectories , it should be equivalent to uniform convergence , so that in standard situations , nothing is lost . this is a difficult task , and it turns out that the various extensions of skorohod s metrics [ ] to functions of several variables [ ] are not suitable for the examples that we consider . in the present paper , we construct such a metric by building on ideas that originate in variational analysis and optimization theory . in the context of minimizatio

We construct a weak convergence theory for the space of bounded functions. We consider empirical copula processes, linear regression and tail dependence function processes. The metric is weak enough to allow statistical applications.

in the past decades , weak convergence theory for stochastic processes has become a standard tool for analyzing the asymptotic properties of various statistics . routinely , weak convergence is considered in the space of bounded functions equipped with the supremum metric . however , there are cases when weak convergence in those spaces fails to hold . examples include empirical copula and tail dependence processes and residual empirical processes in linear regression models in case the underlyi


We use archival data of nasa s chandra x - ray telescope to compile an x - ray light curve of all...

the quasar q2237 + 0305 was discovered in 1984 during a spectroscopic survey of nearby galaxies . the spectrum of the nucleus of the barred spiral galaxy 2237 + 0305 ( =0.0394 ) was found to be superimposed by a quasar component at a redshift of = 1.695 . + the first high resolution observations of the system showed three images of the quasar . this number was soon corrected by who first observed all four known point like quasar images around the core of the galaxy . the images are arranged in a nearly symmetric way , hence the name ` the einstein cross ' . + spectroscopy proved that they are images of a single quasar . the images are separated by up to 1.8 from each other , and are labeled a through d. + after the prediction by and initial theoretical studies ( e.g. , ) , microlensing was first detected in q2237 + 0305 . in fact , this detection of ` quasar microlensing ' was the first evidence for microlensing generally , including stellar microlensing in the galaxy which was not discovered until 1993 . today ` the einstein cross ' is one of the best studied multiply lensed quasars and there have been a lot of monitoring programs in the optical where much microlensing activity has been observed . the quasar has also been detected in the uv , the nir , the mir and the radio regime . however , there is no published light curve of q2237 + 0305 in the x - ray regime yet . + the x - ray emission of q2237 + 0305 was first detected with _ rosat / hri _ observations in 1997 . since then there have been other x - ray observations of q2237 + 0305 like a single spectroscopic observation with _ xmm - newton _ from 2002 ( data set i d : 0110960101 ; pi : watson ) and two _ chandra _ observations . in this paper we study ten archival _ chandra _ observations ranging from january 2006 until january 2007 and compile the first x - ray light curve of q2237 + 0305 . the data we use was taken by the _ chandra x - ray observatory _ in the period between january 9 , 2006 ( julian date

We present a new x - ray emission of the quasar q2237 + 0305 in the xmm - newton regime. The light curve of the system is obtained by using the _ rosat / hri _ observations of the galaxy. We find that the q 2237 + 3305 has a single spectroscopic emission from the nir and mir, which are both observed in the optical.

we use archival data of nasa s chandra x - ray telescope to compile an x - ray light curve of all four images of the quadruply lensed quasar q2237 + 0305 ( =1.695 ) from january 2006 to january 2007 . we fit simulated point spread functions to the four individual quasar images using cash s c - statistic to account for the poisson nature of the x - ray signal . the quasar images display strong flux variations up to a factor of within one month . we can disentangle the intrinsic quasar variability


Previous studies have shown that dipole - bound excited states exist for certain small anions

in the search for carriers of unexplained interstellar absorption spectra , the electronic properties of rarely studied systems offer a viable new avenue of research to explore . the set of as - of - yet unexplained visible to near - infrared peaks known as the diffuse interstellar bands ( dibs ) , for example , has remained a mystery for nearly a century . however , it has been suggested that anions may be responsible for some of the dib features . recent work has shown a relative richness of electronic absorption features below the electronic binding energy ( ebe ) for some anions that exhibit singlet dipole - bound excited states and even some species that appear to possess additional valence excitations for any dipole - bound anion , the corresponding radical must possess large a dipole moment in order for the electron to remain bound within the system . in an ideal situation the dipole moment must be at least greater than 1.625 d and probably closer to 2.5 d typically in a highly diffuse orbital . however , valence ground and excited states may exist below the single dipole - bound state which functions as the upper excitation energy limit since the dipole - bound state excitation energy must be nearly coincident with the ebe . bound excited valence states in molecular anions are rare " . however , some anions are known to exhibit valence electronic excitations , but most of these are open - shell anions where excitations do not have to overcome the additional energy barrier of sorts involved in splitting an electron pair while still remaining below the ebe . negatively charged small fragments or atoms and , especially , carbon chains have been documented to possess bound valence excited states . additionally , some anions , including many with second row atoms , are known to possess triplet excited states above the ground state where the energy splitting between the ground state ( which may either be singlet or triplet ) and the triplet excited state is relati

We present a new study of the electronic properties of the diffuse interstellar bands ( dibs ) in a singlet dipole - bound excited state. We show that the dib is strongly dependent on the electron pair and the dipole moment, but it can be found to be much more robust than the dibe - binding energy. The dibroid excitation energy must be at least greater than 1.625 d and probably closer to 2.5 d typically in a highly diffuse orbital.

previous studies have shown that dipole - bound excited states exist for certain small anions . however , valence excited states have been reported for some closed - shell anions , but those with singlet valence excited states have , thus far , contained a single silicon atom . this work utilizes high - level coupled cluster theory previously shown to reproduce excited state energies to better than 0.1 ev compared with experiment in order to examine the electronic excited state properties of ani


The galactic centre hosts , according to observations , a number of early - type stars

over the past two decades , nearly 200 early - type stars have been revealed in the innermost parsec of our galaxy ( see genzel et al . 2010 for the most recent review ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? observations suggest that these stars are orbiting a highly concentrated mass , which is associated with the compact radio source sgr a*. it is widely accepted that this source is powered by a supermassive black hole ( smbh ) . its mass and distance from the sun are estimated to be approximately and , respectively . according to the most recent observations of , the majority ( 136 ) of the early - type stars observed in the sgr a * region are located at projected distance from the smbh . roughly one half of these stars appear to form a coherently rotating disc - like structure , the so - called clockwise system ( cws ; discovered by * ? ? ? the remaining stars are randomly scattered off the cws plane . nevertheless , some authors report the existence of a second coherent structure at a large angle with respect to the cws the counterclockwise system ( ccws ; first mentioned by * ? ? ? given these two discs , a significant number of the early - type stars are still not belonging to either of the structures . observations have further established that all the early - type stars between and from the smbh are either wolf - rayett stars or o- or early b - stars ( wr / ob stars ) . evolutionary phases of individual stars indicate that all of them have been formed ago within a short period of time , probably not exceeding . the presence of such stars so close to a smbh is rather suprising . in particular , the tidal field of the smbh is strong enough to prevent standard star formation mechanisms . hence , various hypotheses have been suggested to explain the origin and configuration of the wr / ob stars observed in the sgr a * region . in situ fragmentation of a self - gravitating gaseous disc is probably the currently most wide

We present a new study of the early - type stars in the innermost parsec of our galaxy. We find that the first two discs are not wolf - rayett stars or o - or early b - stars, but rather a pair of wolf and ray - like stars. The first disc is a coherently rotating disk, which is associated with the compact radio source sgr a*. It is also possible to detect a second disc, a wolf or rayer -like.

the galactic centre hosts , according to observations , a number of early - type stars . about one half of those which are orbiting the central supermassive black hole on orbits with projected radii form a coherently rotating disc . observations further reveal a massive gaseous torus and a significant population of late - type stars . in this paper , we investigate , by means of numerical -body computations , the orbital evolution of the stellar disc , which we consider to be initially thin . we


We analyze time - resolved spontaneous emission from excitons confined in self - assembled quantum...

semiconductor quantum dots ( qds ) are nanoscale solid state structures that provide three - dimensional quantum confinement of otherwise mobile charge carriers . self - assembled qds of embedded in provide confinement for both electrons and holes in a direct band gap semiconductor . hence , they are optically active with the benefits of a high quantum efficiency and compatibility with existing semiconductor technology . these properties make the qds highly promising light sources for novel optical devices including optical quantum information devices . this has led to an increasing interest in the quantum - optical properties of qds , and major achievements include the demonstration of the purcell effect for qds in solid - state cavities and strong coupling between a single qd and the optical mode of a cavity . very recently also electrical tuning of such quantum photonics devices was demonstrated , which is a significant milestone towards practical all - solid state cavity quantum electrodynamics devices . despite the recent progress , a thorough understanding of the dynamics of light - matter coupling for qds in nanostructured photonic media is still lacking . such an understanding is required for quantitative comparisons between experiment and theory . the problem is two - fold , i.e. a detailed understanding of both the optical part and the electronic part is required . the optical part is described by the local density of optical states ( ldos ) expressing the distribution of modes that the qd can radiate to , while the electronic part is determined by the exciton wavefunction for the qd . here we will investigate an optical system where the ldos can be calculated exactly , and use that to extract detailed information about the qd . our experimental results are compared to a theoretical qd model , and the effect of qd size , material composition , and strain is investigated . such quantitative comparisons of experimental data to simple theoretical qd models ar

We investigate the optical properties of semiconductor quantum dots ( qds ) in nanostructured photonic media. The optical part is defined by the local density of optical states ( ldos ) and the electronic part is determined by the exciton wavefunction for the qD. Our results are compared to a theoretical qc model, and the effect of qb size, material composition, strain is investigated.

we analyze time - resolved spontaneous emission from excitons confined in self - assembled quantum dots placed at various distances to a semiconductor - air interface . the modification of the local density of optical states due to the proximity of the interface enables unambiguous determination of the radiative and non - radiative decay rates of the excitons . from measurements at various emission energies we obtain the frequency dependence of the radiative decay rate , which is only revealed d


Directed sandpile models with different toppling rules are studied by means of numerical...

the classification of sandpile models in their different universality class has been a topic of intensive research in the last decade . however , most of the work has been devoted to models with undirected toppling while their corresponding directed variants has been less studied . from the theoretical side we count with the exact solution for the directed btw model obtained by dhar and ramaswamy , which can be taken as a reference for numerical simulations . on the other hand , pastor - satorras and vespignani has recently reported numerical simulations for the manna model , which puts clear evidence about the classification of the btw and manna directed models in different universality classes . other studies include a directed model with a probabilistic toppling and a recent report concerning the effect of local dissipation on the soc state . the analysis of other directed models , the non abelian zhang model for instance , is of great interested and may give light to the study of their corresponding undirected variants . with this scope three different directed models are investigated by means of numerical simulations . this includes the well known zhang model , the random threshold model ( rt ) , and the btw model under an uniform driving . the influence of a uniform driving in the zhang model has been already discussed in the literature although some aspects are still not clear . however , the same analysis has not been made for models with a discrete toppling rule , like the btw model , where the energy transfer always takes place in discrete units . in this direction narayan and middleton suggested that the btw model under noisy and uniform driving has the same critical behavior . from the numerical data it is concluded that the manna and rt directed models belong to the same universality class , in agreement with the general believe for the corresponding undirected variants . moreover , the data obtained for the zhang model does not satisfy finite - size sc

We study the critical behavior of a random threshold model under noise and uniform driving. The results are obtained for the manna and rt directed models, which belong to the same universality class.

directed sandpile models with different toppling rules are studied by means of numerical simulations in two dimensions , with the purpose of determining the different universality classes . it is concluded that the random - threshold directed model is in the same universality of the manna directed model where multiple toppling events plays a determinant role . the btw model with uniform and noisy driving are found to display the same critical behavior . moreover it is observed that the zhang mod


We present spectral and timing analysis of observations of the accreting x - ray pulsar rxp

2rxp j130159.6 - 635806 , first discovered by the _ rosat _ observatory , was later rediscovered in hard x - rays by the _ integral_/ibis telescope and designated with the name igrj13020 - 6359 . the first comprehensive analysis of the temporal and spectral x - ray properties of this source was done by using data from the _ asca _ , _ bepposax _ , _ integral _ and _ xmm - newton _ observatories . in particular , _ xmm - newton _ data showed coherent pulsations with a period of around 700 s. joint spectral analysis of _ xmm - newton _ and _ integral _ data demonstrated that the spectral shape is very typical for accretion - powered x - ray pulsars ( namely , an absorbed power law with a high - energy cut - off ) . based on 2mass archival data , proposed that the binary companion to 2rxp j130159.6 - 635806 is a be star at a distance of 47 kpc . this suggestion was later confirmed by , who reported the presence of emission lines of hei .0594 m and br(74 ) .1663 m , which are typical for a be star . the spectral type of the optical counterpart was determined to be b0.5ve . the orbital period of the binary remains unknown . x - ray pulsars in binary systems with be companions ( bexrps ) typically manifest themselves as transient sources through either type i ( periodic flares related to the periastron passage ) or type ii outbursts ( powerful rare transient events ) , or a combination of both . 2rxpj130159.6 - 635806 shows several differences from a standard transient bexrp . specifically , it has a relatively low persistent flux , a long pulse period , and it does not demonstrate either type i or type ii outbursts . , however , did report some variability of its x - ray flux . therefore , there are substantial reasons to consider 2rxpj130159.6 - 635806 as a member of the subclass of persistent bexrps . so far , only a few members of this relatively small category of objects have been studied in detail : 4u 0352 + 309/x persei , rx j0146.9 + 6121/ls i + 61 235 , rx j0440

We present a new analysis of the x - ray properties of 2rxp j130159.6 - 605806 in binary systems with be companions ( bexrps ). The spectral type of the optical counterpart to 2rXp, igrj13020 - 659, is b0.5ve and the orbital period of the binary is unknown. We find that the spectra of the two sources are similar to those of the other two sources.

we present spectral and timing analysis of observations of the accreting x - ray pulsar rxp . the source was serendipitously observed during a campaign focused on the gamma - ray binary and was later targeted for a dedicated observation . the spectrum has a typical shape for accreting x - ray pulsars , consisting of a simple power law with an exponential cutoff starting at kev with a folding energy of kev . there is also an indication of the presence of a 6.4 kev iron line in the spectrum at the


An investigation of the processes and in a background magnetic field is presented

the interaction of matter with magnetic fields has long been studied for the important consequences it has for particle dynamics . whether it is from the astrophysical implication of a magnetic field on the structure of a neutron star or to the zeeman shift of energy levels within an atom , the presence of an external magnetic field can open the door to interesting effects not previously seen . the effect of an homogeneous background field on the charged fermion propagator in qed was first studied by schwinger . proper - time method provides the machinery for an exact solution to the altered propagator . recently , a weak field expansion of this method has been applied to demonstrate that there exists enhancements to neutrino - photon interactions that involve charged fermion loops . the goal of this article is to present what effects a magnetic field has on the decays of the which are otherwise forbidden . the landau - yang theorem uses bose symmetry and rotational invariance arguments to prove that a vector particle can not decay into two massless vector particles . that is , the decays and are not allowed . however we can employ the field expansion of schwinger s method to calculate if and to what degree the magnetic field stimulates the decay . we expand just to first order in the magnetic field . this turns out to be a very good approximation considering that the relevant expansion parameter is , where is the mass of the fermion and is its charge . for the lightest of the possible fermions , the electron , the critical field turns out to be of the order . this field is a great deal larger than those magnetic fields produced by very dense white dwarfs , and near the neutron star magnetic field intensity . the calculation is complete to first order , but because of this expansion parameter it is shown that the dominant contributions are from the lightest quarks ( ) for and from the electron in the case . first we briefly introduce the reader to the methodology us

We present a weak field expansion of the landau - yang theorem to calculate the decays of the charged fermion propagator in qed. The calculation is complete to first order in the magnetic field and the dominant contributions are from the lightest quarks for and from the electron in the case.

an investigation of the processes and in a background magnetic field is presented . for homogeneous fields corrections to the charged fermion propagator can be calculated in leading orders of the magnetic field . this work examines the first order contributions of the corrected propagator to decays that are otherwise zero . results of the decay rates for varying field strengths are included .


Using a set of high - resolution -body / sph cosmological simulations with identical initial...

one potential problem of the cold dark matter ( cdm ) cosmology is the mass distributions in the central region of clusters of galaxies . there is yet no consensus emerging from the observations . in general , simulations produce steep inner density profiles for dm halos , while observations of some clusters seem to prefer flat , core - like profiles ( e.g. , * ? ? ? * ) , and others prefer cusped profiles ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? show that the central dm profiles of clusters of galaxies have a slope of about , which is substantially flatter than the inner slope ( ) of the navarro - frenk - white ( nfw ) profile as found in cdm simulations . however , other authors argued that their interpretations are compromised by the assumption of sphericity ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ) . recent observations of strong gravitational lensing have shown that some clusters of galaxies have very high mass concentration parameters ( e.g. , * ? ? ? * ) compared with the average value obtained in the dm simulations . the number of giant arcs predicted by -body simulations may also be somewhat too low to be compatible with observations ( ; but see ; ; ) . it is unclear whether these discrepancies are serious . hence , the systematics in theoretical predictions need to be explored , and the effect of baryons is one of these . baryons can cool via dissipative processes while dm is collisionless , and so their density evolutions may be quite different . although the baryonic matter is only a modest fraction of the total mass ( less than or equal to the universal baryon fraction of 16% , as revealed by the _ wilkinson microwave anistropy probe _ [ wmap ] ; spergel et al . 2003 , 2006 ) , it can nevertheless play a significant role in reshaping the density profiles of the dm halos . for example , the baryons that condense toward the center of dm halos can compress dm by adiabatic contraction . this effect was confirmed in simulations with gas cooling where the

We present a new study of the mass distributions in clusters of galaxies with strong gravitational lensing. We find that the central density profiles of clusters have a slope of about, which is substantially flatter than the inner slope of the navarro - frenk - white ( nfw ) profile as found in cdm simulations. The results are consistent with previous observations of strong gravitationsal lensed clusters, and show that the mass concentration parameters are similar to those obtained by -body simulations in the same way.

using a set of high - resolution -body / sph cosmological simulations with identical initial conditions but run with different numerical setups , we investigate the influence of baryonic matter on the mass distribution of dark halos when radiative cooling is _ not _ included . we compare the concentration parameters of about massive halos with virial mass from to . we find that the concentration parameters for the total mass and dark matter distributions in nonradiative simulations are on averag


We survey several applications of fixed point theorems in the theory of invariant subspaces

one of the most recalcitrant unsolved problems in operator theory is the invariant subspace problem . the question has an easy formulation . does every operator on an infinite dimensional , separable complex hilbert space have a non trivial invariant subspace ? despite the simplicity of its statement , this is a very difficult problem and it has generated a very large amount of literature . we refer the reader to the expository paper of yadav for a detailed account of results related to the invariant subspace problem . in this survey we discuss some applications of fixed point theorems in the theory of invariant subspaces . the general idea is that a fixed point theorem applied to a suitable map yields the existence of invariant subspaces for an operator on a banach space . in section [ compact ] we consider the striking theorem of lomonosov about the existence of invariant subspaces for algebras containing compact operators . the proof of this theorem is based on the schauder fixed point theorem . in section [ local ] we present a recent result of lomonosov , radjavi , and troitsky about the existence of invariant subspaces for localizing algebras . the proof of this result is based on the ky fan fixed point theorem for multivalued maps . the idea of using fixed point theorems for multivalued maps in the search for invariant subspaces was first introduced by androulakis . in section [ burnside ] we consider an extension of burnside s theorem to infinite dimensional banach spaces . this result is originally due to lomonosov . we present a proof of it in a special case that was obtained independently by scott brown and that once again is based on the schauder fixed point theorem . in section [ krein ] we address the existence of invariant subspaces for operators on krein space of indefinite product , and we present a result of albeverio , makarov , and motovilov whose proof uses the banach fixed point theorem . the rest of this section contains some notation , a prec

We discuss some applications of fixed point theorems in the theory of invariant subspaces. The general idea is that a fixed point Theoremus applied to a suitable map yields the existence of in Variant subSpaces for operators on krein space of indefinite product. In this paper we present a proof of it in a special case that was obtained independently by scott brown and that once again is based on the schauder fixed pointtheorematization.

we survey several applications of fixed point theorems in the theory of invariant subspaces . the general idea is that a fixed point theorem applied to a suitable map yields the existence of invariant subspaces for an operator on a banach space . [ 1995/12/01 ] : 47a15 , 47h10 : invariant subspace ; fixed point


Masses for the ( or ) molecular states are systematically computed in the framework of qcd sum rules

recently , the cdf collaboration has reported the observation of a narrow near - threshold structure in the mass spectrum in decays , for which the mass is and the width is . this experimental observation has triggered great interest of many practitioners , and there have already appeared some theoretical interpretations for this new resonance , e.g. refs . . on the whole , is apt to be deciphered as the molecular partner of the charmonium - like state . undoubtedly , the quantitative description of s properties such as mass is quite needed for well understanding its structure , but it is difficult to extract information on the hadronic spectrum from the rather simple lagrangian of qcd . that s because low energy qcd involves a regime where it is futile to attempt perturbative calculations and one has to treat a genuinely strong field in nonperturbative methods . whereas , one can resort to qcd sum rules ( for reviews see and references therein ) , which is a nonperturbative analytic formalism firmly entrenched in qcd . in fact , some authors have studied via qcd sum rules soon after its observation , however , they arrived at different conclusions basing on the molecular picture . on the other hand , it could not be readily excluded for or as possible molecular configuration for without explicit dynamics calculations . catalyzed by the above reasons , we devote to calculate the spectra of the molecular states through qcd sum rules , to see whether can be figured as a molecular state . in our approach , the masses for , , , , , and molecular states are gained . in addition , to improve on the accuracy of qcd sum rule analysis for , the order and contributions are included in ope side . the paper is organized as follows . in sec . [ sec2 ] , qcd sum rules for the molecular states are introduced , and both the phenomenological representation and qcd side are derived , followed by the numerical analysis to extract the hadronic masses in sec . section [ sec4 ] is a brie

We present a new approach to the analysis of the mass spectrum in decays using qcd sum rules. The phenomenological representation and q cm side are derived, followed by numerical analysis to extract the hadronic masses in sec.

masses for the ( or ) molecular states are systematically computed in the framework of qcd sum rules . technically , contributions of the operators up to dimension six are included in operator product expansion ( ope ) . the numerical result for agrees well with the mass for , which supports the molecular configuration for .


Dust in debris disks is generated by collisions among planetesimals

as of the end of 2008 , 228 extrasolar planets around 193 stars had been discovered using radial velocity techniques . most of them are believed to be jupiter - like gas giants , although some may be lower - mass rocky planets . according to the core accretion model , planets are formed by the agglomeration of rocky planetesimals into solid cores . for gas giants , the core accretes a gaseous envelope . the planets may migrate toward the star due to interactions with the disk material , and strong planet planet gravitational scattering may significantly modify orbital parameters . it is also known that many main - sequence stars display infrared and/or submillimeter excess emission due to the presence of debris dust grains ( e.g. , * ? ? ? these grains are replenished by collisions among planetesimals , leftovers of the planet formation process ( backman & paresce 1993 ) . planets orbiting the star can stir the planetesimal population and initiate a collisional cascade , resulting in dust production . the morphology of the disk might be gravitationally shaped by planets orbiting interior to the disk . the common origin of planets and debris disks suggests that a connection may exist between the presence of planets and planetesimals . the relationship between debris disks and planets can be studied by comparing the incidence of excess emission due to debris dust between samples of stars with and without planets . an overview of such studies is presented in tab . [ tab : detection ] . for sun - like stars e.g. hinted at a positive correlation between debris disks and planets ; found no significant correlation ; and claimed that although excess rates for the planet sample are higher , both samples excess rates are consistent at the 1 level . more conclusive results can only be based on larger samples than used in those studies . here we use data from the _ spitzer space telescope _ archive at 24 and 70 m to compare the incidence of debris dust around stars with planets

We present a new study of the incidence of debris dust around stars with and without planets. We compare the incidences of debris Dust around stars and planets in two different samples: the _ spitzer space telescope _ archive at 24 and 70 m, and the data from the spitzeer space telescope archives at 24 m and 70m. The results are consistent with previous studies, but not consistent with current observations.

dust in debris disks is generated by collisions among planetesimals . the existence of these planetesimals is a consequence of the planet formation process , but the relationship between debris disks and planets has not been clearly established . here we analyze spitzer / mips 24 and 70 m data for 150 planet - bearing stars , and compare the incidence of debris disks around these stars with a sample of 118 stars around which planets have been searched for , but not found . together they comprise


The static kottler metric is the schwarzschild vacuum metric extended to include a cosmological...

the cosmological constant , originally included in the field equations to create a static universe , is now included in models of the universe to drive acceleration . how the cosmological constant effects more local scenarios , both static and stationary , is also of interest . the 1918 kottler solution , , describes matter from cosmological constant around a spherical source of mass , creating a generalization of the schwarzschild vacuum solution . the kottler metric is when einstein s field equations are extended to include , birkhoff s theorem extends to the kottler solution as the unique consequence of spherical symmetry . kottler reduces to the vacuum schwarzschild solution when . the kottler spacetime is an einstein space with ricci tensor chrusciel and simon have discussed the classification of static spherically symmetric solutions with . for the spacetime is either de sitter ( ) or anti - de sitter ( ) . its conformal structure has been studied by lake and roeder . the kottler spacetime with is not cosmological since it is spherically symmetric rather than lrs . examining geodesic orbits shows the term corresponds to a repulsive ( ) central force of magnitude . contributes to the periapsis precession of geodesic orbits but does not effect gravitational lensing . this spacetime is petrov type * d * , with , the only non - zero weyl tensor component . only the schwarzschild mass contributes to the weyl tensor , which explains why has no lensing effect . with , one interpretation of in the field equations is a vacuum energy - momentum . in the newtonian limit is recognized as a uniform mass density an upper limit for is equivalent to a vacuum density of gm/ . we will focus on as a backgound atmosphere . with there is a trapped surface ( horizon ) at with mass , the presence of the atmosphere modifies the horizon structure even in the static case , the positions being given by the roots of the cubic function while horizons in both schwarzschild and kottler have

We study the cosmological constant in the 1918 kottler solution, which is an einstein space with ricci tensor. The horizon structure of the spherically symmetric kotler spacetime is studied as a backgound atmosphere. We find that the spectral properties of the surface are not affected by the presence of the atmosphere, but by the existence of a vacuum energy - momentum.

the static kottler metric is the schwarzschild vacuum metric extended to include a cosmological constant . angular momentum is added to the kottler metric by using newman and janis complexifying algorithm . the new metric is the generalization of the kerr spacetime . it is stationary , axially symmetric , petrov type * ii * , and has kerr - schild form.pacs numbers : 04.20.-q , 04.20.jb * contents * {l}% \\ {0pt}a.\ generalizations}\\ {0pt}b.\ our\ generalization}\\ \\ \\ {0pt}a.\ energy - momen


Using hydrodynamic simulations , we investigate the physical properties of gaseous substructures in...

the inner parts of barred galaxies contain interesting gaseous substructures that include dust lanes , nuclear rings , and nuclear spirals ( e.g. , ) . these substructures are thought to form as a result of gas redistribution in galaxies initiated by non - axisymmetric bar torque ( e.g. , ) . understanding their formation and evolution is therefore of crucial importance to understand how the interstellar gas in barred galaxies is driven inward to affect star formation activities in the nuclear regions and potentially fueling of active galactic nuclei ( agn ) . since their spatial locations and shapes are likely to be determined by the bar strength as well as the underlying rotation curve ( e.g. , ) , they may also be used to probe the mass distributions in barred galaxies that are not directly observable . while the bar substructures have been observed for a long time ( e.g. , ) , it is during recent years that high - quality data on their physical properties have been compiled and compared with bar characteristics ( e.g. , ) . there is increasing observational evidence that the shape and size of the bar substructures are determined primarily by the bar strength . for instance , measured the curvature angles of dust lanes for a sample of 9 barred - spiral galaxies , and found that stronger bars favor more straight dust lanes , confirming a theoretical prediction of . by extending the sample size to 55 galaxies , confirmed the results of , although they also found that a large scatter in the fit of the relationship can be reduced if the bar ellipticity is also considered in the fit . more recently , measured the sizes and shapes of nuclear rings in a sample of 107 galaxies , finding that ` stronger bars host smaller rings ' and that the ring ellipticity is in the range of 00.4 . reported from the analysis of 13 nuclear rings that the ring size is well correlated with the compactness of the galaxy mass distribution such that higher mass concentration implies a smaller

We present a new study of the shape and size of nuclear rings in barred galaxies. The results are consistent with previous studies that have shown that stronger bars favor more straight dust lanes, while weaker bars favor smaller rings. We also find that the shape of nuclear ring sizes is well correlated with the compactness of the galaxy mass distribution, suggesting that the larger ring size is associated with the larger mass density.

using hydrodynamic simulations , we investigate the physical properties of gaseous substructures in barred galaxies and their relationships with the bar strength . the gaseous medium is assumed to be isothermal and unmagnetized . the bar potential is modeled as a ferrers prolate with index . to explore situations with differing bar strength , we vary the bar mass relative to the spheroidal component as well as its aspect ratio . we derive expressions as functions of and for the bar strength and


Polarization is an important indicator of stellar evolution , especially for stars evolving from...

a characteristic property of stars evolving from red giant stage to planetary nebulae ( pne ) is polarization ; observed polarization reaches a maximum during the proto - planetary stage and gradually decreases as the star evolves into a pn . polarimetric studies of post - asymptotic giant branch ( agb ) stars by and have helped to identify aspherical morphology shells that originate during mass - loss phase as common features of these objects . quasi - periodic variations in linear polarization are known to be observed in many late - type variables . however , not much work has been done on polarization of carbon stars ; we report here -band polarimetric measurements of a sample of carbon stars at high galactic latitude . polarization of carbon stars are known to show a flatter wavelength dependence than the oxygen - rich stars . stars with circumstellar materials exhibit a certain amount of linear polarization . the degree of polarization increases with asymmetries present in the geometry of the shells . by modeling the observed polarization , it is possible to study the geometry and structure of the shells . polarization models of circumstellar grain scattering shows that graphites do not adequately explain the mean polarimetric behavior of carbon stars . have shown that graphites also do not adequately explain the ir spectra of circumstellar dust envelopes around carbon - rich objects . it was suggested by that graphite formation in circumstellar envelopes is not a very likely process and its likely that carbon grains exist most likely as amorphous carbon . while find no significant variation in polarization for hd 100746 at u , b , i bands , etc . , finds mild wavelength dependence of polarization in the case of a few carbon stars of mira variables . in particular , the polarization was found to increase systematically toward the red in rt pup , uu aur shows a dip in the polarization curve around the band , and x vel shows a larger polarization in the band than

We report -band polarimetric measurements of a sample of carbon stars at high galactic latitude. The observed polarization is found to increase with asymmetries present in the geometry of the shells. It is shown that the polarized gas is amorphous and has a lower polarizing curve than the oxygen - rich star.

polarization is an important indicator of stellar evolution , especially for stars evolving from red - giant stage to planetary nebulae . however , not much is known about the polarimetric properties of the carbon - enhanced metal - poor ( cemp ) stars , although they have been well studied in terms of photometric as well as low- and high - resolution spectroscopy . we report here first - ever estimates of -band polarimetry of a group of cemp stars . -band polarimetry was planned as the -band is


We investigate several categories of integrable - , - , -modules

the category of finite - dimensional representations of a lie algebra is endowed with a natural contravariant involution where indicates dual space . for categories of infinite - dimensional modules is never an involution as . this is why one usually looks for a `` restricted dual '' or a `` continuous dual '' which might still yield a contravariant involution on a given category of infinite - dimensional modules . in this paper we study two categories of infinite - dimensional modules of certain infinite - dimensional lie algebras and show , in particular , that there exists an interesting category of infinite - dimensional representations on which the functor ( 1 ) of algebraic dualization is well - defined and preserves the property of a module to be of finite loewy length . more precisely , we study representations of locally finite lie algebras , i.e. of direct limits of finite - dimensional lie algebras . there are three well - known classical simple locally finite lie algebras , each of them being defined by an obvious direct limit . none of these lie algebras admits non - trivial finite - dimensional representations , and instead one studies integrable representations ( the definition see in section 2 below ) . however , the category of integrable -modules is vast ( and `` wild '' in the technical sense ) , so it is reasonable to look for interesting subcategories . one subcategory we study is the category of integrable weight modules with finite - dimensional weight spaces , and this is obviously an analog of the category of finite - dimensional representations of a classical finite - dimensional lie algebra . it is less obvious that for this category contains some rather interesting simple modules which are not highest weight modules . the first main result of this paper is the proof of the semisimplicity of this category : an extension of hermann weyl s semisimplicity theorem to the classical lie algebras . the above category is clearly not the only reaso

We study two categories of infinite - dimensional modules of certain infinite / dimensional lie algebras and show that there exists an interesting category of infinitely -dimensional representations on which the functor ( 1 ) of algebraic dualization is well - defined and preserves the property of a module to be of finite loewy length.

we investigate several categories of integrable - , - , -modules . in particular , we prove that the category of integrable - , - , -modules with finite - dimensional weight spaces is semisimple . the most interesting category we study is the category of tensor modules . its objects are defined as integrable modules of finite loewy length such that the algebraic dual is also integrable and of finite loewy length . we prove that the simple objects of are precisely the simple tensor modules , i.e.


Experiments on the direction - resolved full - counting statistics of single - electron tunneling...

the second law of thermodynamics states that the entropy of a macroscopic system driven out of equilibrium grows with time , and the dynamics of such a system is irreversible . the entropy of a mesoscopic system also grows in the long - time limit , but it may decrease over sufficiently short periods of time . hence , the entropy production during a time interval is a random variable , characterized by a distribution . the ` fluctuation theorem ' ( ft ) states that the probabilities of positive and negative entropy changes at sufficiently long are related by remarkably , this simple and universal relation remains valid even far from equilibrium . it has been proven for thermostated hamiltonian systems , markovian stochastic processes , quantum systems , and mesoscopic conductors . the ft is fundamentally important for transport theory . one of its consequences is the jarzynski equality , which in turn leads to the 2nd law of thermodynamics . it also leads to the fluctuation - dissipation theorem and onsager symmetry relations , as well as to their extensions to nonlinear transport . the ft was first verified in an experiment measuring the distribution of the work done on a colloidal particle placed in a water flow and trapped by an optical tweezer . by monitoring the position fluctuations it is possible to estimate the work done on the particle . for this classical experiment , as well as for other related ones performed at room temperature , the thermal fluctuations are quite large and the ft has been confirmed . in contrast , experiments for mesoscopic quantum systems were lacking until very recently . let us now discuss the implications of ft for mesoscopic systems . the first experimental test of the ft applied to single - electron transport has been performed recently in ref . a system of two coupled quantum dots in a 2deg at the gaas / algaas interface was operated in the coulomb blockade regime . ( the single - electron charging energy of a single dot was of

The ft is a fundamentally important theory for single - electron transport. It has been recently proved in a classical experiment, as well as in other related ones performed at room temperature. We present an experimental test of the eigenvalues of the fluctuation theorem applied to single - Electron transport, which is based on the jarzynski equality.

experiments on the direction - resolved full - counting statistics of single - electron tunneling allow testing the fundamentally important fluctuation theorem ( ft ) . at the same time , the ft provides a frame for analyzing such data . here we consider tunneling through a double quantum dot system which is coupled capacitively to a quantum point contact ( qpc ) detector . fluctuations of the environment , including the shot noise of the qpc , lead to an enhancement of the effective temperature