Research archive

arXiv papers from December 2002

The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.

  1. M. F. DeCamp, D. A. Reis, A. Cavalieri, P. H. Bucksbaum

    We study coherent strain in (001) Ge generated by an ultrafast laser-initiated high density electron-hole plasma. The resultant coherent pulse is probed by time-resolved x-ray diffraction through changes in the anomalous transmission. The acoustic pulse front is driven by ambipolar diffusion of the electron-hole plasma and propagates into the crystal at supe

  2. I. V. Kanatchikov

    Precanonical quantization of pure Yang-Mills fields, which is based on the covariant De Donder-Weyl (DW) Hamiltonian formalism, and its connection with the functional Schrodinger representation in the temporal gauge are discussed. The YM mass gap problem is related to a finite dimensional spectral problem for a generalized Clifford-valued magnetic Schr\"odin

  3. Harry I. Teplitz, Nicholas R. Collins, Jonathan P. Gardner, Robert S. Hill

    We present the luminosity function of [OII]-emitting galaxies at a median redshift of z=0.9, as measured in the deep spectroscopic data in the STIS Parallel Survey (SPS). The luminosity function shows strong evolution from the local value, as expected. By using random lines of sight, the SPS measurement complements previous deep single field studies. We calc

  4. Brandon C. Kelly, Philip A. Hughes, Hugh D. Aller, Margo F. Aller

    We introduce an algorithm for applying a cross-wavelet transform to analysis of quasiperiodic variations in a time-series, and introduce significance tests for the technique. We apply a continuous wavelet transform and the cross-wavelet algorithm to the Pearson-Readhead VLBI survey sources using data obtained from the University of Michigan 26-m parabloid at

  5. Frederick M. Walter, Tracy L. Beck, Jon A. Morse, Scott J. Wolk

    The 3" pair of B9 stars, HD 28867, is one of the brightest X-ray sources in the Taurus-Auriga star forming region. In this multi-wavelength study, we attempt to deduce the source of the X-ray emission. We show that the East component is the X-ray source. The East component has a near-IR excess and displays narrow absorption lines in the optical, both of whic

  6. Andrew Gould

    I test the completeness of USNO-B detections of high proper-motion (mu>0.18"/yr) stars and the accuracy of its measurements by comparing them to the revised NLTT (rNLTT) catalog of Salim & Gould. For 14.5<V<18.5, only 6% of such stars are missing from USNO-B while another 4% have large errors, mostly too large to be useful. Including both classes, incomplete

  7. Hong Liu, Gregory Moore, Nathan Seiberg

    In this talk we discuss the cosmic singularity. We motivate the need to correct general relativity in the study of singularities, and mention the kind of corrections provided by string theory. We review how string theory resolves time-like singularities with two examples. Then, a simple toy model with lightlike singularities is presented, and studied in clas

  8. Dominic Mayers

    It is believed that superselection rules in quantum mechanics can restrict the possible operation on a qbit. If this was true, the model used by Mayers for the impossibility of bit commitment and by Kitaev for the impossibility of coin flipping would be inadequate. We explain why this is not the case. We show that a charge superselection rule implies no rest

  9. Frank Wilczek

    Some important problems in quantitative QCD will certainly yield to hard work and adequate investment of resources, others appear difficult but may be accessible, and still others will require essentially new ideas. Here I identify several examples in each class.

  10. Antonina N. Fedorova, Michael G. Zeitlin

    We consider an application of variational-wavelet approach to nonlinear collective models of beam/plasma physics: Vlasov/Boltzmann-like reduction from general BBGKY hierachy. We obtain fast convergent multiresolution representations for solutions which allow to consider polynomial and rational type of nonlinearities. The solutions are represented via the mul

  11. Elad Schneidman, William Bialek, Michael J. Berry

    A population of neurons typically exhibits a broad diversity of responses to sensory inputs. The intuitive notion of functional classification is that cells can be clustered so that most of the diversity is captured in the identity of the clusters rather than by individuals within clusters. We show how this intuition can be made precise using information the

  12. Antonina N. Fedorova, Michael G. Zeitlin

    We present an application of variational-wavelet analysis to quasiclassical calculations of solutions of Wigner equations related to nonlinear (polynomial) dynamical problems. (Naive) deformation quantization, multiresolution representations and variational approach are the key points. Numerical calculations demonstrates pattern formation from localized eige

  13. Clifford Henry Taubes

    This article describes various moduli spaces of pseudoholomorphic curves on the symplectization of a particular overtwisted contact structure on S^1 x S^2. This contact structure appears when one considers a closed self dual form on a 4-manifold as a symplectic form on the complement of its zero locus. The article is focussed mainly on disks, cylinders and t

  14. Zheng Yin

    N=1 and 2 superconformal boundary conditions are shown to be the consequence of a boundary on the worldsheet superspace with positive codimension in the anticommuting subspace. In addition to the well-known boundary conditions, I also find two new infinite series of N=2 boundary states. Their free field realizations are given. A self-contained development of

  15. Blaise Aguera y Arcas, Adrienne L. Fairhall, William Bialek

    A spiking neuron ``computes'' by transforming a complex dynamical input into a train of action potentials, or spikes. The computation performed by the neuron can be formulated as dimensional reduction, or feature detection, followed by a nonlinear decision function over the low dimensional space. Generalizations of the reverse correlation technique with whit

  16. Bhupinder Singh Anand

    If we assume the Thesis that any classical Turing machine T, which halts on every n-ary sequence of natural numbers as input, determines a PA-provable formula, whose standard interpretation is an n-ary arithmetical relation f(x1, >..., xn) that holds if, and only if, T halts, then standard PA can model the state of a deterministic universe that is consistent

  17. G. G. Barnafoldi, P. Levai, G. Papp, G. Fai

    Perturbative QCD results on pion production are presented in proton-proton, proton-nucleus and nucleus-nucleus collisions from CERN SPS up to RHIC energy. A K_{jet}(s, p_T, Q) factor obtained from jet production is applied to perform next-to-leading order calculations. Using the intrinsic transverse momentum (k_T) we determined transverse momentum spectra fo

  18. Alex J. Feingold

    This is an expository introduction to fusion rules for affine Kac-Moody algebras, with major focus on the algorithmic aspects of their computation and the relationship with tensor product decompositions. Many explicit examples are included with figures illustrating the rank 2 cases. New results relating fusion coefficients to tensor product coefficients are

  19. Jeeva Anandan, Naresh Dadhich, Parampreet Singh

    We present an action principle formulation for the study of motion of an extended body in General Relativity in the limit of weak gravitational field. This gives the classical equations of motion for multipole moments of arbitrary order coupling to the gravitational field. In particular, a new force due to the octupole moment is obtained. The action also yie

  20. Jose A. de Azcarraga, Jose M. Izquierdo, Moises Picon, Oscar Varela

    We study how to generate new Lie algebras $\mathcal{G}(N_0,..., N_p,...,N_n)$ from a given one $\mathcal{G}$. The (order by order) method consists in expanding its Maurer-Cartan one-forms in powers of a real parameter $\lambda$ which rescales the coordinates of the Lie (super)group $G$, $g^{i_p} \to \lambda^p g^{i_p}$, in a way subordinated to the splitting

  21. Beatriz Gato-Rivera

    This is a brief introduction to the subject of Conformal Field Theory on surfaces with boundaries and crosscaps, which describes the perturbative expansion of open string theory.

  22. Dirk Hundertmark, Werner Kirsch, Simone Warzel

    We determine the leading low-energy fall-off of the integrated density of states of a magnetic Schroedinger operator with repulsive Poissonian random potential in case its single impurity potential has a slow anisotropic decay at infinity. This so-called magnetic Lifshits tail is shown to coincide with the one of the corresponding classical integrated densit

  23. Pierre Henry-Labordere, Bernard Julia, Louis Paulot

    The correspondence between del Pezzo surfaces and field theory models over the complex numbers or for split real forms is extended to other real forms, in particular to those compatible with supersymmetry. Specifically, all theories of the Magic triangle that reduce to the pure supergravities in four dimensions correspond to singular real del Pezzo surfaces

  24. I. T. Obukhovsky, V. I. Kukulin, M. M. Kaskulov, P. Grabmayr

    The impact of the short-range $N\Delta$ interaction on the pion photoproduction processes off the deuteron in the $\Delta$-resonance region is studied in the framework of recently proposed dressed-bag model. A common dressing procedure for bare three- and six-quark states is used to describe both the pion decay widths of baryon resonances and the effective $

  25. T. V. Shishkina, V. V. Makarenko

    The exclusive reaction $ \gamma\gamma\to f \bar{f} \gamma$ is considered as the possible calibration process on the linear photon collider. We analyse the energy spectrum and total cross section dependence on the detector parameters at various initial beam helicities.

  26. J. Blümlein, H. Böttcher

    In this talk we summarize main results of a recent determination of the polarized deeply inelastic parton distributions to NLO from the world data. In the analysis the LO and NLO parton densities and their $1\sigma$ statistical errors were derived and parameterized. The strong coupling constant $\alpha_s(M_Z^2)$ is determined $\alpha_s(M_Z^2) = 0.113 \pm 0.0

  27. S. K. Sahay

    We investigate the matching of continuous gravitational wave (CGW) signals in an all sky search with reference to Earth based laser interferometric detectors. We consider the source location as the parameters of the signal manifold and templates corresponding to different source locations. It has been found that the matching of signals from locations in the

  28. Eric L Swenson

    We give sufficient conditions for a group of homeomorphisms of a Peano continuum X without cut-points to be a convergence group. The condition is that there is a collection of convergence subgroups whose limit sets `cut up' X in the correct fashion. This is closely related to the result in [E Swenson, Axial pairs and convergence groups on S^1, Topology 39 (2

  29. H. Marion, F. Pereira Dos Santos, M. Abgrall, S. Zhang

    Over five years we have compared the hyperfine frequencies of 133Cs and 87Rb atoms in their electronic ground state using several laser cooled 133Cs and 87Rb atomic fountains with an accuracy of ~10^{-15}. These measurements set a stringent upper bound to a possible fractional time variation of the ratio between the two frequencies : (d/dt)ln(nu_Rb/nu_Cs)=(0

  30. Lev Vaidman, Zion Mitrani

    Methods for measuring an integral of a classical field via local interaction of classical bits or local interaction of qubits passing through the field one at a time are analyzed. A quantum method, which has an exponentially better precision than any classical method we could see, is described.

  31. P. Vielva, E. Martinez-Gonzalez, J. E. Gallegos, L. Toffolatti

    We present an estimation of the point source (PS) catalogue that could be extracted from the forthcoming ESA Planck mission data. We have applied the Spherical Mexican Hat Wavelet (SMHW) to simulated all-sky maps that include CMB, Galactic emission (thermal dust, free-free and synchrotron), thermal Sunyaev-Zel'dovich effect and PS emission, as well as instru

  32. Petr Alexa

    Possible theoretical electromagnetic paths between the ground state and the isomeric state at 75.3 keV in 180Ta are discussed in the framework of the two-quasiparticle-plus-phonon model and the standard axially-symmetric rotor model including Coriolis mixing. Experimental transition rates from the isomeric state to the ground state via observed mediating sta

  33. D. V. Ahluwalia-Khalilova

    We argue that existing doubly special relativities may not be operationally distinguishable from the special relativity. In the process we point out that some of the phenomenologically motivated modifications of dispersion relations, and arrived conclusions, must be reconsidered. Finally, we reflect on the possible conceptual issues that arise in quest for a

  34. Matt Mackie, Anssi Collin, Juha Javanainen

    Collective two-color photoassociation of a freely-interacting 87Rb Bose-Einstein condensate is theoretically examined, focusing on stimulated Raman adiabatic passage (STIRAP) from an atomic to a stable molecular condensate. In particular, Drummond et al. [Phys. Rev. A 65, 063619 (2002); cond-mat/0110578] have predicted that particle-particle interactions can

  35. Arun K. Pati

    Quantum information theory has revolutionized the way in which information is processed using quantum resources such as entangled states, local operations and classical communications. Two important protocols in quantum communications are quantum teleportation and remote state preparation. In quantum teleportation neither the sender nor the receiver know the

  36. M. Jourdan, N. Blümer, H. Adrian

    Superconducting SrTiO_{3-\delta} was obtained by annealing single crystalline SrTiO_3 samples in ultra high vacuum. An analysis of the V(I) characteristics revealed very small critical currents I_c which can be traced back to a unavoidable doping inhomogeneity. R(T) curves were measured for a range of magnetic fields B at I<<I_c, thereby probing only the sam

  37. Miao Li

    We discuss the sizes of a black hole in the M theory pp-wave background, and how the transverse size can be reproduced in the matrix model.

  38. R. Passante, F. Persico

    A time-dependent Casimir-Polder force is shown to arise during the time evolution of a partially dressed two-level atom. The partially dressed atom is obtained by a rapid change of an atomic parameter such as its transition frequency, due to the action of some external agent. The electromagnetic field fluctuations around the atom, averaged over the solid ang

  39. David Garber

    In this note we prove a decomposition related to the affine fundamental group and the projective fundamental group of a line arrangement and a reducible curve with a line component. We give some applications to this result.

  40. T. V. Shishkina, I. B. Marfin

    The cross section for deep inelastic lepton-nucleon scattering with arbitrary polarized scattering fermions is calculated within the electroweak Standard Model and non-minimal gauge models with additional neutral boson. The Lorentz-invariant formulas for cross section and all types of electroweak asymmetries, polarized, charge-polarized, charged, including t

  41. Kiyoshi Tamaki, Masato Koashi, Nobuyuki Imoto

    We prove the unconditional security of the Bennett 1992 protocol, by using a reduction to an entanglement distillation protocol initiated by a local filtering process. The bit errors and the phase errors are correlated after the filtering, and we can bound the amount of phase errors from the observed bit errors by an estimation method involving nonorthogonal

  42. Kiyoshi Tamaki, Masato Koashi, Nobuyuki Imoto

    The security of two-state quantum key distribution against individual attack is estimated when the channel has losses and noises. We assume that Alice and Bob use two nonorthogonal single-photon polarization states. To make our analysis simple, we propose a modified B92 protocol in which Alice and Bob make use of inconclusive results and Bob performs a kind

  43. A. A. Bytsenko, Yu. P. Goncharov

    The natural extension of Schwarzschild metric to the case of nonzero cosmological constant $\Lambda$ known as the Kottler metric is considered and it is discussed under what circumstances the given metric could describe the Schwarzschild black hole immersed in a medium with nonzero energy density. Under the latter situation such an object might carry topolog

  44. R. Brustein, S. P. de Alwis, E. G. Novak

    We conduct a systematic search for a viable string/M-theory cosmology, focusing on cosmologies that include an era of slow-roll inflation, after which the moduli are stabilized and the Universe is in a state with an acceptably small cosmological constant. We observe that the duality relations between different cosmological backgrounds of string/M-theory modu

  45. Seungjoon Hyun, Jaemo Park, Hyeonjoon Shin

    We work out boundary conditions for the covariant open string in the type IIA plane wave background, which corresponds to the D-branes in the type IIA theory. We use the kappa symmetric string action and see what kind of boundary conditions should be imposed to retain kappa symmetry. We find half BPS as well as quarter BPS branes and the analysis agrees with

  46. Andrés Vina

    The rational cohomology of a coadjoint orbit ${\cal O}$ is expressed as tensor product of the cohomology of other coadjoint orbits ${\cal O}_k$, with $ \hbox{dim} {\cal O}_k< \hbox{dim} {\cal O}$.

  47. V. S. Starovoitov

    A random matrix theory approach is applied in order to analyze the localization properties of local spectral density for a generic system of coupled quantum states with strong static imperfection in the unperturbed energy levels. The system is excited by an external periodic field, the temporal profile of which is close to monochromatic one. The shape of loc

  48. Harry J. Lipkin

    The past leaves the surprising experimental successes of the simple constituent quark model to be expained by QCD. Surprising agreement with experiment from simple Sakharov-Zeldovich model (1966) having quarks with effective masses and hyperfine interaction. Nambu's (1966) Colored quarks with gauge gluons gave mass spectrum with only $qqq$ and $\bar q$ bound

  49. Zvi Bern

    In this talk, the recent breakthrough in two-loop perturbative calculations is reviewed, with emphasis on the applications to phenomenological studies. The recent precision measurement of the anomalous magnetic moment of the muon by the Brookhaven g-2 collaboration is also used as an illustrative example of the importance of Standard Model precision perturba

  50. P. Baseilhac, M. Stanishkov

    Exact vacuum expectation values of the third level descendent fields $<(\partial\phi)^3({\bar\partial}\phi)^3e^{a\phi}>$ in the Bullough-Dodd model are proposed. By performing quantum group restrictions, we obtain $<L_{-3}{\bar L}_{-3}{\Phi}_{lk}>$ in perturbed minimal conformal field theories.

  51. Kiyoshi Igusa

    This paper gives a short summary of the central role played by Ed Brown's "twisting cochains" in higher Franz-Reidemeister (FR) torsion and higher analytic torsion. Briefly, any fiber bundle gives a twisting cochain which is unique up to fiberwise homotopy equivalence. However, when they are based, the difference between two of them is a higher algebraic K-t

  52. Tatyana Sharpee, Nicole C. Rust, William Bialek

    We propose a method that allows for a rigorous statistical analysis of neural responses to natural stimuli which are non-Gaussian and exhibit strong correlations. We have in mind a model in which neurons are selective for a small number of stimulus dimensions out of a high dimensional stimulus space, but within this subspace the responses can be arbitrarily

  53. Mikhail Lyubich

    The goal of this technical note is to show that the geometry of generalized parabolic towers cannot be essentially bounded. It fills a gap in author's paper "Combinatorics, geomerty and attractors of quasi-quadratic maps", Annals of Math., 1992.

  54. R. S. Singh, B. K. Sinha, N. K. Lohani

    It is found from Maxwell's equations that the magnetic field lines are good analogues of relativistic strings. It is shown that the super-conducting current in the neutron star's interior causes local rotation of magnetic flux tubes carrying quantized flux.

  55. Mark Walker, Masaki Mori, Michiko Ohishi

    Cold, dense gas clouds have been proposed as a major component of the Galactic dark matter; such clouds can be revealed by the gamma-ray emission which arises from cosmic-rays interacting with the gas. If this dark matter component is clustered then highly luminous GeV sources result, preferentially at low to mid Galactic latitudes where they lie within the

  56. Masayasu Harada

    In this talk I summarize main features of the vector manifestation (VM) which was recently proposed as a novel manifestation of the Wigner realization of chiral symmetry in which the symmetry is restored at the critical point by the massless degenerate pion (and its flavor partners) and the rho meson (and its flavor partners) as the chiral partner. I show ho

  57. F. Loran

    We show that after mapping each element of a set of second class constraints to the surface of the other ones, half of them form a subset of abelian first class constraints. The explicit form of the map is obtained considering the most general Poisson structure. We also introduce a proper redefinition of second class constraints that makes their algebra symp

  58. A. B. Souchkov, J. R. Simpson, H. D. Drew, M. Quijada

    We have measured the optical conductivity of single crystal LuMnO3 from 10 to 45000 cm-1 at temperatures between 4 and 300 K. A symmetry allowed on-site Mn $d$-$d$ transition near 1.7 eV is observed to blue shift (~0.1 eV) in the antiferromagnetic state due to Mn-Mn superexchange interactions. Similar anomalies are observed in the temperature dependence of t

  59. R. Loll

    In these lecture notes, I describe the motivation behind a recent formulation of a non-perturbative gravitational path integral for Lorentzian (instead of the usual Euclidean) space-times, and give a pedagogical introduction to its main features. At the regularized, discrete level this approach solves the problems of (i) having a well-defined Wick rotation,

  60. M. Y. Poon, D. Merritt

    We construct models of triaxial galactic nuclei containing central black holes using the method of orbital superposition, then verify their stability by advancing N-body realizations of the models forward in time. We assume a power-law form for the stellar density, rho ~ 1/r and 1/r^2; these correspond approximately to the nuclear density profiles of bright

  61. Javier Ballesteros-Paredes

    Molecular clouds (MC) are the densest and coldest component of the interstellar gas, and the sites of star formation. They are also turbulent and fractal and their masses and sizes span several orders of magnitude. It is also generally believed that they are close to Virial equilibrium (VE). Since this statement has been questioned by a number of authors, wi

  62. Axel Krause

    We review a recent proposal towards a microscopic understanding of the entropy of non-supersymmetric spacetimes -- with emphasis on the Schwarzschild black hole. The approach is based at an intermediate step on the description of the non-supersymmetric spacetime in terms of dual Euclidean brane pairs of type-II string-theory or M-theory. By counting specific

  63. M. Ausloos, K. Ivanova

    We generalize the momentum indicator idea taking into account the volume of transactions as a multiplicative factor. We compare returns obtained following strategies based on the classical or the generalized technical analysis, taking into account a sort of risk investor criterion.

  64. Y. J. Uemura

    Extensive muon spin relaxation measurements have been performed to determine the magnetic field penetration depth in high-Tc cuprate superconductors with simple hole doping, Zn-doping, overdoping, and formation of static SDW nano islands. System dependence of $n_{s}/m^{*}$ (superconducting carrier density / effective mass) reveals universal correlations betw

  65. S. Bize, S. A. Diddams, U. Tanaka, C. E. Tanner

    Over a two-year duration, we have compared the frequency of the 199Hg+ 5d106s 2S 1/2 (F=0)<-> 5d9 6s2 2D 5/2 (F=2) electric-quadrupole transition at 282 nm with the frequency of the ground-state hyperfine splitting in neutral 133Cs. These measurements show that any fractional time variation of the ratio nu(Cs)/nu(Hg) between the two frequencies is smaller th

  66. J. Berges, Sz. Borsanyi, J. Serreau

    We solve the nonequilibrium dynamics of a 3+1 dimensional theory with Dirac fermions coupled to scalars via a chirally invariant Yukawa interaction. The results are obtained from a systematic coupling expansion of the 2PI effective action to lowest non-trivial order, which includes scattering as well as memory and off-shell effects. The dynamics is solved nu

  67. Harry I. Teplitz, Nicholas R. Collins, Jonathan P. Gardner, Robert S. Hill

    In the first three years of operation STIS obtained slitless spectra of approximately 2500 fields in parallel to prime HST observations as part of the STIS Parallel Survey (SPS). The archive contains almost 300 fields at high galactic latitude (|b|>30) with spectroscopic exposure times greater than 3000 seconds. This sample contains 220 fields (excluding spe

  68. Jonathan P. McCammond, Daniel T. Wise

    A group is coherent if all its finitely generated subgroups are finitely presented. In this article we provide a criterion for positively determining the coherence of a group. This criterion is based upon the notion of the perimeter of a map between two finite 2-complexes which is introduced here. In the groups to which this theory applies, a presentation fo

  69. V. V. Flambaum, E. V. Shuryak

    We follow our previous paper on possible cosmological variation of weak scale (quark masses) and strong scale, inspired by data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra. In this work we identify the {\em strange quark mass} $m_s$ as the most important quantity, and the {\em sigma me

  70. P. Nalbach

    The dielectric constant of amorphous solids at low temperatures is governed by the dynamics of tunneling systems, small groups of atoms which tunnel between quasi equivalent potential minima. Recent experiments showed that at temperatures below 20 mK various glasses exhibit memory for a previously applied electric bias field. A first sweep of an electric bia

  71. P. Coleman, C. Pepin

    Although the concept of a quantum phase transition has been known since the nineteen seventies, their importance as a source of radical transformation in metallic properties has only recently been appreciated. A quantum critical point forms an essential singularity in the phase diagram of correlated matter. We discus new insights into the nature of this phen

  72. T. A. Costi

    We study electronic transport through a strongly interacting quantum dot by using the finite temperature extension of Wilson&#39;s numerical renormalization group (NRG) method. This allows the linear conductance to be calculated at all temperatures and in particular at very low temperature where quantum fluctuations and the Kondo effect strongly modify the t

  73. Serguei Ktitorov

    The problem of the vortex structure in the lattice modele of superconductors has been reduced to the nonlinear map problem characteristic for the fractal theory.

  74. Pierre Del Moral, Arnaud Doucet

    This paper shows how one can use Sequential Monte Carlo methods to perform what is typically done using Markov chain Monte Carlo methods. This leads to a general class of principled integration and genetic type optimization methods based on interacting particle systems.

  75. Long-Long Feng, Chi-Wang Shu, Meng-Ping Zhang

    We describe a newly developed cosmological hydrodynamics code based on the weighted essentially non-oscillatory (WENO) schemes for hyperbolic conservation laws. High order finite difference WENO schemes are designed for problems with piecewise smooth solutions containing discontinuities, and have been successful in applications for problems involving both sh

  76. Kyungjin Ahn, Paul R. Shapiro

    We study the formation and evolution of self-interacting dark matter (SIDM) halos. We find analytical, fully cosmological similarity solutions taking account of the collisional interaction of SIDM particles. This interaction results in a thermal conductivity that heats the halo core and flattens its density profile. These similarity solutions are relevant to

  77. Miho Koma, Atsushi Hosaka, Hiroshi Toki

    Transitions among excited nucleons are studied within a non-relativistic quark model with a deformed harmonic oscillator potential. The transition amplitudes are factorized into the $l$-th moment and a geometrical factor. This fact leads to an analogous result to the ``Alaga-rule'' for baryons.

  78. Yoshiaki Koma

    The structure of the Abelian-projected (AP) flux tube in SU(2) gauge theory in the maximally Abelian gauge is studied by applying the Hodge decomposition to the Abelian Wilson loop. It is shown that the profile of the AP flux tube has the same structure as the classical flux tube solution in the dual Abelian Higgs model, which is composed of a Coulombic and

  79. Manuel I. Marques, Jose M. Borreguero, H. Eugene Stanley, Nikolay V. Dokholyan

    We study cold denaturation of proteins at high pressures. Using multicanonical Monte Carlo simulations of a model protein in a water bath, we investigate the effect of water density fluctuations on protein stability. We find that above the pressure where water freezes to the dense ice phase ($\approx2$ kbar), the mechanism for cold denaturation with decreasi

  80. V. Faraoni, F. I. Cooperstock

    The idea that the universe has zero total energy when one includes the contribution from the gravitational field is reconsidered. A Hamiltonian is proposed as an energy for the exact equations of FRW cosmology: it is then shown that this energy is constant. Thus open and critically open FRW universes have the energy of their asymptotic state of infinite dilu

  81. Massimo Blasone, Paulo Pires Pacheco, Hok Wan Chan Tseung

    By resorting to recent results on the relativistic currents for mixed (flavor) fields, we calculate a space-time dependent neutrino oscillation formula in Quantum Field Theory. Our formulation provides an alternative to existing approaches for the derivation of space dependent oscillation formulas and it also accounts for the corrections due to the non-trivi

  82. Miho Koma, Yoshiaki Koma, Dietmar Ebert, Hiroshi Toki

    The effective string action of the color-electric flux tube in the dual Ginzburg-Landau (DGL) theory is studied by performing a path-integral analysis by taking into account the finite thickness of the flux tube. A modified Yukawa interaction appears as a boundary contribution and is reduced into the ordinary Yukawa interaction in the London Limit.

  83. Yoshiaki Koma, Miho Koma, Hiroshi Toki

    We discuss the Casimir scaling hypothesis on the nonperturbative force in terms of the dual superconducting picture of the QCD vacuum by calculating the string tensions of flux tubes associated with static charges in various SU(3) representations in the dual Ginzburg-Landau (DGL) theory.

  84. N. Chernov, J. L. Lebowitz

    We study numerically and theoretically (on a heuristic level) the time evolution of a gas confined to a cube of size $L^3$ divided into two parts by a piston with mass $M_L \sim L^2$ which can only move in the $x$-direction. Starting with a uniform ``double-peaked'' (non Maxwellian) distribution of the gas and a stationary piston, we find that (a) after an i

  85. N. Chernov, J. L. Lebowitz, Ya. Sinai

    We continue the study of the time evolution of a system consisting of a piston in a cubical container of large size $L$ filled with an ideal gas. The piston has mass $M\sim L^2$ and undergoes elastic collisions with $N\sim L^3$ gas particles of mass $m$. In a previous paper, Lebowitz, Piasecki and Sinai considered a scaling regime, with time and space scaled

  86. M. Nishimura, Y. Tanii

    In the context of the AdS/CFT correspondence the general form of a three-form flux perturbation to the AdS_5 x S^5 solution in the type IIB supergravity which preserves N=2 supersymmetry is obtained. The arbitrary holomorphic function appearing in the N=1 case studied by Grana and Polchinski is restricted to a quadratic function of the coordinates transverse

  87. Daniel C. Galehouse

    Spinors have played an essential but enigmatic role in modern physics since their discovery. Now that quantum-gravitational theories have started to become available, the inclusion of a description of spin in the development is natural and may bring about a profound understanding of the mathematical structure of fundamental physics. A program to attempt this

  88. V. V. Ezhela, J. R. Cudell, P. Gauron, K. Kang

    Nowadays, scientific databases have become the bread-and-butter of particle physicists. These databases must be maintained and checked repeatedly to insure the accuracy of their content. The COMPETE collaboration aims at motivating data maintenance via the interfacing of theory and experiment at the database level. The database concept then needs to be suppl

  89. T. Padmanabhan, T. Roy Choudhury

    Current cosmological observations show a strong signature of the existence of a dark energy component with negative pressure. The most obvious candidate for this dark energy is the cosmological constant (with the equation of state w_X=p/\rho=-1), which, however, raises several theoretical difficulties. This has led to models for dark energy component which e

  90. Vladimir Pestov

    Let $F\subseteq H\subseteq G$ be closed subgroups of a locally compact group. In response to a 1972 question by Eymard, we construct an example where the homogeneous factor-space $G/F$ is amenable in the sense of Eymard-Greenleaf, while $H/F$ is not. (In our example, $G$ is discrete.) As a corollary which answers a 1990 question by Bekka, the induced represe

  91. Yu-xi Liu, Adam Miranowicz, Masato Koashi, Nobuyuki Imoto

    The entanglement of excitonic states in a system of $N$ spatially separated semiconductor microcrystallites is investigated. The interaction among the different microcrystallites is mediated by a single-mode cavity field. It is found that the symmetric sharing of the entanglement (measured by the concurrence) between any pair of the excitonic state with $N$

  92. J. Bajer, A. Miranowicz, R. Tanas

    It is well known that the optical Kerr effect can be a source of highly squeezed light, however the analytical limit of the noise suppression has not been found yet. The process is reconsidered and an analytical estimation of the optimal quadrature noise level is presented. The validity of the new scaling law is checked numerically and analytically.

  93. Martin Goldstern, Saharon Shelah

    A clone on a set X is a set of finitary operations on X which contains all the projections and is closed under composition. The set of all clones forms a complete lattice Cl(X) with greatest element O, the set of all finitary operations. For finite sets X the lattice is "dually atomic": every clone other than O is below a coatom of Cl(X). It was open whether

  94. Andrei Frolov, Lev Kofman

    We consider the quasi-de Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quasi-de Sitter apparent horizon and set it equal to the change of the entropy (1/4 of the area) multiplied by the temperature, dE=TdS. Remarkably, this thermodynamic law reproduces the Friedmann equati

  95. Marcelo Fiore, Tom Leinster

    In many everyday categories (sets, spaces, modules, ...) objects can be both added and multiplied. The arithmetic of such objects is a challenge because there is usually no subtraction. We prove a family of cases of the following principle: if an arithmetic statement about the objects can be proved by pretending that they are complex numbers, then there also

  96. Michele Schiavoni, Laurent Sanchez-Palencia, Francois-Regis Carminati, Ferruccio Renzoni

    We examine the stimulated light scattering onto the propagation modes of a dissipative optical lattice. We show that two different pump-probe configurations may lead to the excitation, via different mechanisms, of the same mode. We found that in one configuration the scattering on the propagation mode results in a resonance in the probe transmission spectrum

  97. Michele Schiavoni, Francois-Regis Carminati, Laurent Sanchez-Palencia, Ferruccio Renzoni

    We have observed the phenomenon of stochastic resonance on the Brillouin propagation modes of a dissipative optical lattice. Such a mode has been excited by applying a moving potential modulation with phase velocity equal to the velocity of the mode. Its amplitude has been characterized by the center-of-mass (CM) velocity of the atomic cloud. At Brillouin re

  98. Fernando Szechtman

    We show that in characteristic 2, the Steinberg representation of the symplectic group Sp(2n,q), q a power of an odd prime p, has two irreducible constituents lying just above the socle that are isomorphic to the two Weil modules of degree (q^n-1)/2.

  99. S. L. Sessions, D. Belitz

    An effective field theory is derived that describes the quantum critical behavior of itinerant ferromagnets as the transition is approached from the ferromagnetic phase. This complements a recent study of the critical behavior on the paramagnetic side of the phase transition, and investigates the role of the ferromagnetic Goldstone modes near criticality. We

  100. Gerhard Hummer, Ioannis G. Kevrekidis

    We present a ``coarse molecular dynamics'' approach and apply it to studying the kinetics and thermodynamics of a peptide fragment dissolved in water. Short bursts of appropriately initialized simulations are used to infer the deterministic and stochastic components of the peptide motion parametrized by an appropriate set of coarse variables. Techniques from