July 2006 arXiv papers — page 6

Helmut G. Katzgraber, Gergely T. Zimanyi

We study the return point as well as the complementary point memory effects numerically with paradigmatic models for random magnets and show that already simple systems with Ising spin symmetry can reproduce the experimental results of Pierce et al. where both memory effects become more pronounced for increasing disorder and return point memory is always bet

Dmitri A. Uzdensky

The main subject of my talk is the question: in what kind of astrophysical systems magnetic reconnection is interesting and/or important? To address this question, I first put forward three general criteria for selecting the relevant astrophysical environments. Namely, reconnection should be: fast; energetically important; and observable. From this, I deduce

Hagai Netzer, Benny Trakhtenbrot

We present line and continuum measurements for 9818 SDSS type-I active galactic nuclei (AGNs) with z le 0.75. The data are used to study the four dimensional space of black hole mass, normalized accretion rate (Ledd), metalicity and redshift. The main results are: 1. Ledd is smaller for larger mass black holes at all redshifts. 2. For a given black hole mass

J. H. Kastner, M. Richmond, N. Grosso, D. A. Weintraub

We present Chandra X-ray Observatory monitoring observations of the recent accretion outburst displayed by the pre-main sequence (pre-MS) star V1647 Ori. The X-ray observations were obtained over a period beginning prior to outburst onset in late 2003 and continuing through its apparent cessation in late 2005, and demonstrate that the mean flux of the spatia

Arjen van der Wel, Marijn Franx, Stijn Wuyts, Pieter G. van Dokkum

We determine the importance of redshift-dependent systematic effects in the determination of stellar masses from broad band spectral energy distributions (SEDs), using high quality kinematic and photometric data of early-type galaxies at z~1 and z~0. We find that photometric masses of z~1 galaxies can be systematically different, by up to a factor of 2, from

A. Aragon-Salamanca, A. G. Bedregal, M. R. Merrifield

We test the hypothesis that S0 galaxies are the descendants of fading spirals whose star formation has been shut down, by using the properties of their globular cluster (GC) systems. We estimate the amount by which the GC specific frequency (number of GCs per unit V-band luminosity) is enhanced in S0s relative to spirals. If the transformation hypothesis is

V. V. Sokolov, G. S. Bisnovatyi-Kogan, V. G. Kurt, Yu. N. Gnedin

The typical spectra of gamma-ray bursts (GRBs) are discussed in the context of the compactness problem for GRB sources and how it is resolved in the popular fireball model. In particular, observational (model-independent) constraints on the collimation of the gamma-rays and the dependence of the collimation angle on the photon energy are considered. The fact

D. R. Lorimer, A. J. Faulkner, A. G. Lyne, R. N. Manchester

[ABRIDGED] We present the discovery and follow-up observations of 142 pulsars found in the Parkes 20-cm multibeam pulsar survey of the Galactic plane. These new discoveries bring the total number of pulsars found by the survey to 742. In addition to tabulating spin and astrometric parameters, along with pulse width and flux density information, we present or

A. Misiriotis, E. M. Xilouris, J. Papamastorakis, P. Boumis

We use the COBE/DIRBE (1.2, 2.2, 60, 100, 140, and 240 $μ$m) maps and the COBE/FIRAS spectra (for the wavelength range 100 - 1000 $μ$m) to constrain a model for the spatial distribution of the dust, the stars, and the gas in the Milky Way. By assuming exponential axisymmetric distributions for the dust and the stars and by performing the corresponding radiat

Nicola Bennert, Bruno Jungwiert, Stefanie Komossa, Martin Haas

Spatially resolved emission-line spectroscopy is a powerful tool to determine the physical conditions in the narrow-line region (NLR) of active galactic nuclei (AGNs). We recently used optical long-slit spectroscopy to study the NLRs of a sample of six Seyfert-2 galaxies. We have shown that such an approach, in comparison to the commonly used [OIII] narrow-b

Alexei G. Kritsuk, Rick Wagner, Michael L. Norman, Paolo Padoan

We present the results of three-dimensional simulations of supersonic Euler turbulence with grid resolutions up to 1024^3 points. Our numerical experiments describe nonmagnetized driven turbulent flows with an isothermal equation of state and an rms Mach number of 6. We demonstrate that the inertial range scaling properties of turbulence in this strongly com

George D. Becker, Michael Rauch, Wallace L. W. Sargent

We examine the evolution of the IGM Ly-alpha optical depth distribution using the transmitted flux probability distribution function (PDF) in a sample of 63 QSOs spanning absorption redshifts 1.7 < z < 5.8. The data are compared to two theoretical optical depth distributions: a model distribution based on the density distribution of Miralda-Escude et al. (20

Kerstin E. Kunze

The perturbative approach to stochastic inflation is used to determine the spectrum of density fluctuations and gravitational waves due to the coarse grained field. The amplitude of the curvature fluctuation spectrum, the spectral index and the running of the spectral index are in general found to be smaller than in the standard approach to inflation. Furthe

Marek Krasnansky

We show that in arbitrary even dimension, the two-loop scalar QED Heisenberg-Euler effective action can be reduced to simple one-loop quantities, using just algebraic manipulations, when the constant background field satisfies F^2 = -f^2 I, which in four dimensions coincides with the condition for self-duality, or definite helicity. This result relies on new

Adrian Collister, Ofer Lahav, Chris Blake, Russell Cannon

We describe the construction of MegaZ-LRG, a photometric redshift catalogue of over one million luminous red galaxies (LRGs) in the redshift range 0.4 < z < 0.7 with limiting magnitude i < 20. The catalogue is selected from the imaging data of the Sloan Digital Sky Survey Data Release 4. The 2dF-SDSS LRG and Quasar (2SLAQ) spectroscopic redshift catalogue of

Jun Zhang, Lam Hui, Zoltan Haiman

We develop an analytic approach to study inhomogeneous reionization on large scales by solving the equations of ionization balance and radiative transfer to first order in perturbations. Given the spatial distribution and spectrum of the ionizing sources, our formalism can be used to predict the large scale power spectra of fluctuations in the abundances of

Misao Sasaki, Jussi Valiviita, David Wands

We use the delta N -formalism to investigate the non-Gaussianity of the primordial curvature perturbation in the curvaton scenario for the origin of structure. We numerically calculate the full probability distribution function allowing for the non-instantaneous decay of the curvaton and compare this with analytic results derived in the sudden-decay approxim

A. Babin, A. Figotin

We study nonlinear systems of hyperbolic (in a wider sense) PDE&#39;s in entire d-dimensional space describing wave propagation with the initial data in the form of a finite sum of wavepackets referred to as multi-wavepackets. The problem involves two small parameters beta and rho where: (i) (1/beta) is a factor describing spatial extension of the wavepacket

T. Hahn, S. Heinemeyer, F. Maltoni, G. Weiglein

We present results for the SM and MSSM Higgs-boson production cross sections at the Tevatron and the LHC. The SM cross sections are a compilation of the state-of-the-art theoretical predictions. The MSSM cross sections are obtained from the SM ones by means of an effective coupling approximation, as implemented in FeynHiggs. Numerical results have been obtai

A. Y. Lokhov

This PhD dissertation is devoted to a non-perturbative study of QCD correlators. The main tool that we use is lattice QCD. We concentrated our efforts on the study of the main correlators of the pure Yang - Mills theory in the Landau gauge, namely the ghost and the gluon propagators. We are particularly interested in determining the $\Lqcd$ parameter. It is

Syksy Rasanen

We discuss the physics of backreaction-driven accelerated expansion. Using the exact equations for the behaviour of averages in dust universes, we explain how large-scale smoothness does not imply that the effect of inhomogeneity and anisotropy on the expansion rate is small. We demonstrate with an analytical toy model how gravitational collapse can lead to

Afif Siddiki, Tugrul Hakioglu

This paper has been withdrawn by the first author due to disagreement with experiments.

H. Bombin, M. A. Martin-Delgado

We construct an exactly solvable Hamiltonian acting on a 3-dimensional lattice of spin-$\frac 1 2$ systems that exhibits topological quantum order. The ground state is a string-net and a membrane-net condensate. Excitations appear in the form of quasiparticles and fluxes, as the boundaries of strings and membranes, respectively. The degeneracy of the ground

H. Schatz, K. E. Rehm

We review the nuclear astrophysics aspects of accreting neutron stars in X-ray binaries. We summarize open astrophysical questions in light of recent observations and their relation to the underlying nuclear physics. Recent progress in the understanding of the nuclear physics, especially of X-ray bursts, is also discussed.

Craig van Coevering

We give a correspondence between toric 3-Sasaki 7-manifolds S and certain toric Sasaki-Einstein 5-manifolds M. These 5-manifolds are all diffeomorphic to k#(S^2\times S^3), where k=2b_2(S)+1, and are given by a pencil of Sasaki embeddings of M in S and are given concretely by the zero set of a component of the 3-Sasaki moment map. It follows that there are i

V. P. Gusynin, S. G. Sharapov, J. P. Carbotte

The intensity as well as position in energy of the absorption lines in the infrared conductivity of graphene, both exhibit features that are directly related to the Dirac nature of its quasiparticles. We show that the evolution of the pattern of absorption lines as the chemical potential is varied encodes the information about the presence of the anomalous l

Robert Ewaschuk, Peter D. Turney

It has been argued that a central objective of nanotechnology is to make products inexpensively, and that self-replication is an effective approach to very low-cost manufacturing. The research presented here is intended to be a step towards this vision. We describe a computational simulation of nanoscale machines floating in a virtual liquid. The machines ca

Erik Sjöqvist, David Kult, Johan Åberg

Abelian and non-Abelian geometric phases, known as quantum holonomies, have attracted considerable attention in the past. Here, we show that it is possible to associate nonequivalent holonomies to discrete sequences of subspaces in a Hilbert space. We consider two such holonomies that arise naturally in interferometer settings. For sequences approximating sm

P. Valko, M. R. Gomes, TA Girard

The nucleation of the superconductive phase in macroscopic type-I foils in a slow, continuously decreasing perpendicular magnetic field is observed to first occur at the field $H_{c3}$, and reinitiate at $H_{c2}$. The observed variation of $H_{c2}$ with temperature further yields Ginzburg-Landau parameters for the materials approximately a factor 2 below tab

N. N. Nikolaev, W. Schäfer

At the partonic level, a typical final state in small-x deep inelastic scattering off nuclei and hard proton-nucleus collisions can be characterized by the multiplicity of color-excited nucleons. Within reggeon field theory, each color-excited nucleon is associated with the unitarity cut of the pomeron exchanged between the projectile and nucleus. In this co

Julio I. de Vicente

We study the separability of bipartite quantum systems in arbitrary dimensions using the Bloch representation of their density matrix. This approach enables us to find an alternative characterization of the separability problem, from which we derive a necessary condition and sufficient conditions for separability. For a certain class of states the necessary

The BABAR Collaboration, B. Aubert

We observe a new D_s meson with mass (2856.6 +/- 1.5_{stat.} +/- 5.0_{syst.}) MeV/c^2 and width (48 +/- 7_{stat.} +/- 10_{syst.}) MeV decaying into D^0 K^+ and D^+K^0_S. In the same mass distributions we also observe a broad structure with mass (2688 +/- 4_{stat.} +/- 3_{syst.}) MeV/c^2 and width (112 +/- 7_{stat.} +/- 36_{syst.}) MeV. To obtain this result

Daniel Lenz, Peter Mueller, Ivan Veselić

We provide an ergodic theorem for certain Banach-space valued functions on structures over $\ZZ^d$, which allow for existence of frequencies of finite patterns. As an application we obtain existence of the integrated density of states for associated finite-range operators in the sense of convergence of the distributions with respect to the supremum norm. The

Moshe Kamensky

The motivation for this paper is to extend the known model theoretic treatment of differential Galois theory to the case of linear difference equations (where the derivative is replaced by an automorphism.) The model theoretic difficulties in this case arise from the fact that the corresponding theory ACFA does not eliminate quantifiers. We therefore study g

Jonathan Brundan

We prove that the center of each degenerate cyclotomic Hecke algebra associated to the complex reflection group of type B_d(l) consists of symmetric polynomials in its commuting generators. The classification of the blocks of the degenerate cyclotomic Hecke algebras is an easy consequence. We then deduce that the center of an integral block of parabolic cate

Bernd Ammann, Emmanuel Humbert

Let $M$ be a compact manifold with a metric $g$ and with a fixed spin structure $χ$. Let $λ\_1^+(g)$ be the first non-negative eigenvalue of the Dirac operator on $(M,g,χ)$. We set $$τ(M,χ):= \sup \inf λ\_1^+(g)$$ where the infimum runs over all metrics $g$ of volume 1 in a conformal class $[g\_0]$ on $M$ and where the supremum runs over all conformal classe

Jean-Luc Marichal, Michael J. Mossinghoff

Using combinatorial methods, we derive several formulas for the volume of convex bodies obtained by intersecting a unit hypercube with a halfspace, or with a hyperplane of codimension 1, or with a flat defined by two parallel hyperplanes. We also describe some of the history of these problems, dating to Polya&#39;s Ph.D. thesis, and we discuss several applic

Boris Pioline

In these lecture notes, we review some recent developments on the relation between the macroscopic entropy of four-dimensional BPS black holes and the microscopic counting of states, beyond the thermodynamical, large charge limit. After a brief overview of charged black holes in supergravity and string theory, we give an extensive introduction to special and

N. Mallick, P. -P. Cortet, S. Santucci, S. G. Roux

We study the roughness of a crack interface in a sheet of paper. We distinguish between slow (sub-critical) and fast crack growth regimes. We show that the fracture roughness is different in the two regimes using a new method based on a multifractal formalism recently developed in the turbulence literature. Deviations from monofractality also appear to be di

P. -F. Braun, B. Urbaszek, T. Amand, X. Marie

We show that optical pumping of electron spins in individual InGaAs quantum dots leads to strong nuclear polarisation that we measure via the Overhauser shift (OHS) in magneto-photoluminescence experiments between 0 and 4T. We find a strongly non-monotonous dependence of the OHS on the applied magnetic field, with a maximum nuclear polarisation of 40% for in

B. Skoric, T. U. Vladimirova, M. Celik, J. C. Talstra

We review the fingerprinting scheme by Tardos and show that it has a much better performance than suggested by the proofs in Tardos&#39; original paper. In particular, the length of the codewords can be significantly reduced. First we generalize the proofs of the false positive and false negative error probabilities with the following modifications: (1) we r

Enrico Calzavarini, Thomas H. van den Berg, Federico Toschi, Detlef Lohse

Single-point hot-wire measurements in the bulk of a turbulent channel have been performed in order to detect and quantify the phenomenon of preferential bubble accumulation. We show that statistical analysis of the bubble-probe colliding-times series can give a robust method for investigation of clustering in the bulk regions of a turbulent flow where, due t

S. M. Roy, D. Atkinson, G. Auberson, G. Mahoux

An eight parameter family of the most general nonnegative quadruple probabilities is constructed for EPR-Bohm-Aharonov experiments when only 3 pairs of analyser settings are used. It is a simultaneous representation of 3 Bohr-incompatible experimental configurations valid for arbitrary quantum states.

O. Linnyk, S. Leupold, U. Mosel

We calculate the effects of next-to-leading order perturbative QCD as well as of the quark transverse motion and off-shellness on the Drell-Yan process cross section. By studying the s->infinity behaviour of the cross section in these approaches, we find that the effects of quark off-shellness and intrinsic-k_T parametrize those of higher twists. In particul

V. M. Lashkin, A. I. Yakimenko, O. O. Prikhodko

We study the bound states of two-dimensional bright solitons in nonlocal nonlinear media. The general properties and stability of these multisolitary structures are investigated analytically and numerically. We have found that a steady bound state of coherent nonrotating and rotating solitary structures (azimuthons) can exist above some threshold power. A di

Kalvis M. Jansons

We consider both the effect of particle inertia on stochastic Stokes&#39; drift, and also a related process which could be considered as a crude model of stochastic Stokes&#39; drift driven by an eddy diffusivity. In the latter, the stochastic forcing is a stable OU process rather than Brownian motion. We show that the eddy Stokes&#39; drift velocity has a p

D. Asner, CLEO Collaboration

Due to the quantum correlation between the pair-produced D0 and D0bar from the decay of the psi(3770), the time-integrated single and double tag decay rates depend on charm mixing amplitudes, doubly-Cabibbo-suppressed amplitudes, and the relative strong phase delta between D0 and D0bar decays to identical final states. Using 281 pb^{-1} collected with the CL

B. Kerbikov, E. V. Luschevskaya

We present the evidence that crossover, fluctuation phenomena and possible Anderson transition are the precursors of quark matter formation.

Martin Guessmann, Axel Pelster, Guenter Wunner

We generalize a model of Haeussler and von der Malsburg which describes the self-organized generation of retinotopic projections between two one-dimensional discrete cell arrays on the basis of cooperative and competitive interactions of the individual synaptic contacts. Our generalized model is independent of the special geometry of the cell arrays and desc

E. Perfetto

We consider two disconnected Luttinger liquids which are coupled at $t=0$ through chiral density-density interactions. Both for $t<0$ and $t \geq 0$ the system is exactly solvable by means of bosonization and this allows to evaluate analytically the time-dependence of correlation functions. We find that in the long-time limit the critical exponent governing

M. Wouters, I. Carusotto

The threshold of triply resonant optical parametric oscillation in a semiconductor microcavity in the strong coupling regime is investigated. Because of the third-order nature of the excitonic nonlinearity, a variety of different behaviours is observed thanks to the interplay of parametric oscillation and optical bistability effects. The behaviour of the sig

Jonathan Rocher, Mairi Sakellariadou

D-term inflation is one of the most interesting and versatile models of inflation. It is possible to implement naturally D-term inflation within high energy physics, as for example SUSY GUTs, SUGRA, or string theories. D-term inflation avoids the $η$-problem, while in its standard form it always ends with the formation of cosmic strings. Given the recent thr

Longhua Jiang, Jinwu Ye

Bilayer quantum Hall system (BLQH) differ from its single layer counterparts (SLQH) by its symmetry breaking ground state and associated neutral gapless mode in the pseudo-spin sector. Due to the gapless mode, qualitatively good groundstate and low energy excited state wavefunctions at any finite distance is still unknown. We investigate this important open

Oscar Iglesias, Amilcar Labarta, Xavier Batlle

Some of the main experimental observations related to the occurrence of exchange bias in magnetic systems are reviewed, focusing the attention on the peculiar phenomenology associated to nanoparticles with core/shell structure as compared to thin film bilayers. The main open questions posed by the experimental observations are presented and contrasted to exi

P. Muehlich, V. Shklyar, S. Leupold, U. Mosel

We calculate the spectral function of the omega meson in nuclear matter at zero temperature by means of the low-density theorem. The omega N forward scattering amplitude is calculated within a unitary coupled-channel effective Lagrangian model that has been applied successfully to the combined analysis of pion- and photon-induced reactions. While the peak of

Rob P. Olling

We investigate how the uncertainty on the Hubble constant (H_0) affects the uncertainty in the Equation of State (EOS) of Dark Energy and the total density of the Universe (Omega_tot). We use the approximate relations between the cosmological parameters [Spergel etal (2007)] and use error-propagation to estimate the effects of improving the CMB parameters an

Bobby S. Acharya, Francesco Benini, Roberto Valandro

Type IIA flux compactifications with O6-planes have been argued from a four dimensional effective theory point of view to admit stable, moduli free solutions. We discuss in detail the ten dimensional description of such vacua and present exact solutions in the case when the O6-charge is smoothly distributed. In the localised case, the solution is a half-flat

Sezgin Aygun, Melis Aygun, Ismail Tarhan

This paper has excessive overlap with the following papers also written by the authors or their collaborators: gr-qc/0607110, gr-qc/0607115, gr-qc/0607119, gr-qc/0607109, gr-qc/0607103, gr-qc/0607089, gr-qc/0602012, gr-qc/0608024, and others.

Luigi Accardi, Andreas Boukas

We introduce a new renormalization for the powers of the Dirac delta function. We show that this new renormalization leads to a second quantized version of the Virasoro sector $w_{\infty}$ of the extended conformal algebra with infinite symmetries $W_{\infty}$ of Conformal Field Theory. In particular we construct a white noise (boson) representation of the $

Giulia Rotundo, Mauro Navarra

A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further

A. B. Lahanas

The most recent observations by the WMAP satellite provided us with data of unprecedented accuracy regarding the parameters describing the Standard Cosmological Model. The current matter-energy density of the Universe is close to its critical value of which 73% is attributed to Dark Energy, 23% to Cold Dark Matter and only 4% is ordinary matter of baryonic n

K. Davison, P. M. Dolukhanov, G. R. Sarson, A. Shukurov

We present a mathematical model, based on the compilation and statistical processing of radiocarbon dates, of the transition from the Mesolithic to the Neolithic, from about 7,000 to 4,000 BC in Europe. The arrival of the Neolithic is traditionally associated with the establishment of farming-based economies; yet in considerable areas of north-eastern Europe

Emmanuel Sérié

We formulate a Yang-Mills action principle for noncommutative connections on an endomorphism algebra of a vector bundle. It is shown that there is an influence of the topology of the vector bundle onto the structure of the vacuums of the theory in a non common way. This model displays a new kind of symmetry breaking mechanism. Some mathematical tools are dev

Luis F. Alday, Jan de Boer, Ilies Messamah

In this paper we construct a detailed map from pure and mixed half-BPS states of the D1-D5 system to half-BPS solutions of type IIB supergravity. Using this map, we can see how gravity arises through coarse graining microstates, and we can explicitly confirm the microscopic description of conical defect metrics, the M=0 BTZ black hole and of small black ring

Zhi-zhong Xing, Shun Zhou

We propose a particularly economical neutrino mass model, in which there are only two right-handed Majorana neutrinos of ${\cal O}(1)$ TeV and their masses are highly degenerate. Its novel Yukawa-coupling texture together with the seesaw mechanism allows us to achieve the normal neutrino mass hierarchy with $m^{}_1 = 0$ and a nearly tri-bimaximal neutrino mi

S. Trippel, J. Mikosch, R. Berhane, R. Otto

The absolute photodetachment cross section of OH- anions at a rotational and translational temperature of 170K is determined by measuring the detachment-induced decay rate of the anions in a multipole radio-frequency ion trap. In comparison with previous results, the obtained cross section shows the importance of the initial rotational state distribution. Us

Wolfgang J. Duschl, Markward Britsch

We derive a viscosity from gravitational instability in self-gravitating accretion disks, which has the required properties to account for the observed fast formation of the first super-massive black holes in highly redshifted quasars and for the cosmological evolution of the black hole-mass distribution.

Alessandra Agostini, Giovanni Amelino-Camelia, Michele Arzano, Antonino Marcianó

Over these past few years several quantum-gravity research groups have been exploring the possibility that in some Planck-scale nonclassical descriptions of spacetime one or another form of nonclassical spacetime symmetries might arise. One of the most studied scenarios is based on the use of Hopf algebras, but previous attempts were not successful in derivi

R. Eguchi, M. Taguchi, M. Matsunami, K. Horiba

The temperature ($T$) dependent metal-insulator transition (MIT) in VO$_2$ is investigated using bulk sensitive hard x-ray ($\sim$ 8 keV) valence band, core level, and V 2$p-3d$ resonant photoemission spectroscopy (PES). The valence band and core level spectra are compared with full-multiplet cluster model calculations including a coherent screening channel.

S. V. Maleyev, V. P. Plakhty, S. V. Grigoriev, A. I. Okorokov

Magnon Bose condensation (BC)in the symmetry breaking magnetic field is a result of unusual form of the Zeeman energy, which has terms linear in the spin-wave operators and terms mixing excitations differ in the Wave-vector of the magnetic structure. The following examples are considered: simple easy-plane tetragonal antiferromagnets (AF), frustrated AF fami

Izumi Hachisu, Mariko Kato

We calculate many different nova light curves for a variety of white dwarf masses and chemical compositions, with the assumption that free-free emission from optically thin ejecta dominates the continuum flux. We show that all these light curves are homologous and a universal law can be derived by introducing a ``time scaling factor.&#39;&#39; The template l

Toshiyasu Arai, Naohi Eguchi

Bellantoni and Cook have given a function-algebra characterization of the polynomial-time computable functions via an unbounded recursion scheme which is called safe recursion. Inspired by their work, we characterize the exponential-time computable functions with the use of a safe variant of nested recursion.

Takayuki Myo, Satoru Sugimoto, Kiyoshi Kato, Hiroshi Toki

We study the characteristics of the tensor correlation in $^4$He using a shell model type method. We treat the tensor force explicitly by performing a configuration-mixing calculation in the $2p2h$ basis and include single-particle states up to intermediately high angular momenta. We adopt the Gaussian expansion method for the quantitative description of the

Xun Jia, Sudip Chakravarty

We consider an Ising spin-chain in a random transverse magnetic field and compute the zero temperature wave vector and frequency dependent dynamic structure factor numerically by using Jordan-Wigner transformation. Two types of distributions of magnetic fields are introduced. For a rectangular distribution, a dispersing branch is observed, and disorder tends

Nikodem J. Poplawski

The field equations in $f(R)$ gravity derived from the Palatini variational principle and formulated in the Einstein conformal frame yield a cosmological term which varies with time. Moreover, they break the conservation of the energy--momentum tensor for matter, generating the interaction between matter and dark energy. Unlike phenomenological models of int

Zhi-Wei Wang, Jian Li, Yun-Feng Huang, Yong-Sheng Zhang

We present a scheme for simulating the quantum network of quantum estimation proposed by A. K. Ekert et al. [Phys. Rev. Lett. 88, 217901 (2002)]. We experimentally implement the scheme with linear optical elements. We perform overlap measurements of two single-qubit states and entanglement-witness measurements of some two-qubit states. In addition, it can al

C. M. Chandrashekar, R. Srikanth, Subhashish Banerjee

We study some discrete symmetries of unbiased (Hadamard) and biased quantum walk on a line, which are shown to hold even when the quantum walker is subjected to environmental effects. The noise models considered in order to account for these effects are the phase flip, bit flip and generalized amplitude damping channels. The numerical solutions are obtained

James A. Stickney, Dana Z. Anderson, Alex A. Zozulya

In the last several years considerable efforts have been devoted to developing Bose-Einstein Condensate (BEC)-based devices for applications such as fundamental research, precision measurements and integrated atom optics. Such devices capable of complex functionality can be designed from simpler building blocks as is done in microelectronics. One of the most

W. D. Banks, M. Z. Garaev, D. R. Heath-Brown, I. E. Shparlinski

We show that for any fixed $\eps>0$, there are numbers $δ>0$ and $p_0\ge 2$ with the following property: for every prime $p\ge p_0$ and every integer $N$ such that $p^{1/(4\sqrt{e})+\eps}\le N\le p$, the sequence $1,2,...,N$ contains at least $δN$ quadratic non-residues modulo $p$. We use this result to obtain strong upper bounds on the sizes of the least qu

A. Retzker, M. B. Plenio

A laser cooling scheme for trapped ions is presented which is based on the fast dynamical Stark shift gate, described in [Jonathan etal, PRA 62, 042307]. Since this cooling method does not contain an off resonant carrier transition, low final temperatures are achieved even in traveling wave light field. The proposed method may operate in either pulsed or con

M. Trupke, J. Metz, A. Beige, E. A. Hinds

We report on recent developments in the integration of optical microresonators into atom chips and describe some fabrication and implementation challenges. We also review theoretical proposals for quantum computing with single atoms based on the observation of photons leaking through the cavity mirrors. The use of measurements to generate entanglement can re

Elio Conte, Andrei Khrennikov, Joseph P. Zbilut

It is given a preliminary discussion on the ontic nature of quantum states to be intended as potentialities and on the central role of spin to be considered as the basic essence of quantum mechanical reality. The possible fundamental role of potentialities and of spin is evidenced in the framework of physical as well as of biological reality. After such prel

Yu-Ao Chen, Tao Yang, An-Ning Zhang, Zhi Zhao

The correlations between two qubits belonging to a three-qubit system can violate the Clauser-Horne-Shimony-Holt-Bell inequality beyond Cirel&#39;son&#39;s bound [A. Cabello, Phys. Rev. Lett. 88, 060403 (2002)]. We experimentally demonstrate such a violation by 7 standard deviations by using a three-photon polarization-entangled Greenberger-Horne-Zeilinger s

I. Mazumdar, A. R. P. Rau, V. S. Bhasin

Asymmetric resonances in elastic n+$^{19}$C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+$^{18}$C system when none of the pairs is bound or some of them only weakly bound. By fitting to the general resonance shape described by Fano, we extract resonance position, width, and the &#34;Fano

I. Fuentes-Schuller, P. Barberis-Blostein

We present a family of many-body models which are exactly solvable analytically. The models are an extended n-body interaction Lipkin-Meshkov-Glick model which considers spin-flip terms which are associated with the interaction of an external classical field which coherently manipulates the state of the system in order to, for example, process quantum inform

Che-Ming Li, Li-Yi Hsu, Wei-Yang Lin, Yueh-Nan Chen

We provide a novel criterion for identifying quantum correlation, which allows us to find connections between Bell type inequalities, entanglement detection, and correlation. We utilize the criterion to construct witness operators that can detect genuine multi-qubit entanglement with fewer local measurements. The connection between identifications of quantum

Zhang-yin Wang, Zhan-jun Zhang

A three-party scheme for securely sharing an arbitrary unknown single-qutrit state is presented. Using a general Greenberger-Horne-Zeilinger (GHZ) state as the quantum channel among the three parties, the quantum information (i.e., the qutrit state) from the sender can be split in such a way that the information can be recovered if and only if both receivers

C. F. McCormick, V. Boyer, E. Arimondo, P. D. Lett

We have measured -3.5 dB (-8.1 dB corrected for losses) relative intensity squeezing between the probe and conjugate beams generated by stimulated, nondegenerate four-wave mixing in hot rubidium vapor. Unlike early observations of squeezing in atomic vapors based on saturation of a two-level system, our scheme uses a resonant nonlinearity based on ground-sta

Raul Toral, Claudio J. Tessone

For some models of relevance in the social sciences we review some examples in which system size plays an important role in the final outcome of the dynamics. We discuss the conditions under which changes of behavior can appear only when the number of agents in the model takes a finite value. Those changes of behavior can be related to the apparent phase tra

Manas Kumar Roy

Propagation of sound beam diffracted from a circular aperture in far-field region has been studied in this paper by the method of angular spectrum representation and stationary phase method. This nonparaxial theory is useful when beam angle is not very small and the wavelength $λ$ is comparable to aperture diameter $a$ unlike the situation in paraxial approx

Christian Pierre

The two quantizations of QFT,as well as the attempt of unifying it with general relativity,lead us to consider that the internal structure of an elementary fermion must be twofold and composed of three embedded internal (bi)structures which are vacuum and mass (physical) bosonic fields decomposing into packets of pairs of strings behaving like harmonic oscil

G. Bormetti, E. Cisana, G. Montagna, O. Nicrosini

Reliable calculations of financial risk require that the fat-tailed nature of prices changes is included in risk measures. To this end, a non-Gaussian approach to financial risk management is presented, modeling the power-law tails of the returns distribution in terms of a Student-$t$ (or Tsallis) distribution. Non-Gaussian closed-form solutions for Value-at

Y. Alhassid, S. Liu, H. Nakada

We introduce spin projection methods in the shell model Monte Carlo approach and apply them to calculate the spin distribution of level densities for iron-region nuclei using the complete $(pf+g_{9/2})$-shell. We compare the calculated distributions with the spin-cutoff model and extract an energy-dependent moment of inertia. For even-even nuclei and at low

Hongfei Zhang, Wei Zuo, Junqing Li, G. Royer

The alpha decay half-lives of the recently produced isotopes of the 112, 114, 116 and 118 nuclei and decay products have been calculated in the quasi-molecular shape path using the experimental Qalpha value and a Generalized Liquid Drop Model including the proximity effects between nucleons in the neck or the gap between the nascent fragments. Reasonable est

H. Susanto, P. G. Kevrekidis, B. A. Malomed, R. Carretero-Gonzalez

We investigate fundamental localized modes in 2D lattices with an edge (surface). Interaction with the edge expands the stability area for ordinary solitons, and induces a difference between perpendicular and parallel dipoles; on the contrary, lattice vortices cannot exist too close to the border. Furthermore, we show analytically and numerically that the ed

V. U. Pierce, Fei-Ran Tian

We study the Whitham equations for the fifth order KdV equation. The equations are neither strictly hyperbolic nor genuinely nonlinear. We are interested in the solution of the Whitham equations when the initial values are given by a step function. We classify the step like initial data into eight different types. We construct self-similar solutions for each

S. Gekle, J. Main, T. Bartsch, T. Uzer

We establish a hierarchical ordering of periodic orbits in a strongly coupled multidimensional Hamiltonian system. Phase space structures can be reconstructed quantitatively from the knowledge of periodic orbits alone. We illustrate our findings for the hydrogen atom in crossed electric and magnetic fields.

Michael Aizenman, Robert Sims, Shannon L. Starr

The Sherrington-Kirkpatrick spin glass model has been studied as a source of insight into the statistical mechanics of systems with highly diversified collections of competing low energy states. The goal of this summary is to present some of the ideas which have emerged in the mathematical study of its free energy. In particular, we highlight the perspective

C. Delhomme, M. Pouzet, G. Sagi, N. Sauer

The \textit{age} of a relational structure $\mathfrak A$ of signature $μ$ is the set $age(\mathfrak A)$ of its finite induced substructures, considered up to isomorphism. This is an ideal in the poset $Ω_μ$ consisting of finite structures of signature $μ$ and ordered by embeddability. If the structures are made of infinitely many relations and if, among thos

Kevin Keating, David P. Roberts

We compute the arithmetic intersection numbers of certain Heegner divisors on integral models of Shimura curves over Q. Our formulas generalize the formulas of Gross-Kohnen-Zagier for intersection numbers of Heegner divisors on integral models of modular curves.