March 2002 arXiv papers — page 27

A. M. Jayannavar, Colin Benjamin

Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering in such systems is presented and also a relatively new model based on wave attenuation is introduced. The problem of Aharonov-Bohm(AB) oscillations in conductance of a mesoscopic ring is studied. We have shown that conductance is symm

Daniel F. Litim

Within the exact renormalisation group, the scaling solutions for O(N) symmetric scalar field theories are studied to leading order in the derivative expansion. The Gaussian fixed point is examined for d>2 dimensions and arbitrary infrared regularisation. The Wilson-Fisher fixed point in d=3 is studied using an optimised flow. We compute critical exponents a

Eric Hayashi, Julio F. Navarro, James E. Taylor, Joachim Stadel

We investigate the evolution of substructure in cold dark matter halos using N-body simulations of tidal stripping of substructure halos (subhalos) within a static host potential. We find that halos modeled following the Navarro, Frenk & White (NFW) mass profile lose mass continuously due to tides from the massive host, leading to the total disruption of sat

Daniel F. Litim, Jan M. Pawlowski

Gauge theories in axial gauges are studied using Exact Renormalisation Group flows. We introduce a background field in the infrared regulator, but not in the gauge fixing, in contrast to the usual background field gauge. It is shown how heat-kernel methods can be used to obtain approximate solutions to the flow and the corresponding Ward identities. Expansio

Chuan-Hung Chen, C. Q. Geng

We study the exclusive decays of $B\to K^{*}\ell^+ \ell^-$ within the framework of the perturbative QCD (PQCD). We obtain the form factors for the $B\to K^{*}$ transition in the large recoil region, where the PQCD for heavy $B$ meson decays is reliable. We find that our results for the form factors at $q^2=0$ are consistent with those from most of the other

Claudio Chamon, Chetan Nayak

We consider the problem of the superconductor-insulator transition in the presence of disorder, assuming that the fermionic degrees of freedom can be ignored so that the problem reduces to one of Cooper pair localization. Weak disorder drives the critical behavior away from the pure critical point, initially towards a diffusive fixed point. We consider the e

R. F. Werner, A. S. Holevo

A conjecture arising naturally in the investigation of additivity of classical information capacity of quantum channels states that the maximal purity of outputs from a quantum channel, as measured by the p-norm, should be multiplicative with respect to the tensor product of channels. We disprove this conjecture for p>4.79. The same example (with p=infinity)

G. Bressi, G. Carugno, R. Onofrio, G. Ruoso

We report on the measurement of the Casimir force between conducting surfaces in a parallel configuration. The force is exerted between a silicon cantilever coated with chromium and a similar rigid surface and is detected looking at the shifts induced in the cantilever frequency when the latter is approached. The scaling of the force with the distance betwee

B. L. Hu

In quantum computation, it is of paramount importance to locate the parameter space where maximal coherence can be preserved in the qubit system. In recent years environment-induced decoherence based the quantum Brownian motion (QBM) models have been applied to two level systems (2LS) interacting with an electromagnetic field, leading to the general belief t

Cristian S. Calude, Boris Pavlov

Is there any hope for quantum computing to challenge the Turing barrier, i.e. to solve an undecidable problem, to compute an uncomputable function? According to Feynman's '82 argument, the answer is {\it negative}. This paper re-opens the case: we will discuss solutions to a few simple problems which suggest that {\it quantum computing is {\it theore

Malte Henkel

In contrast to a widely held opinion, the three-body problem has an analytic solution. This solution was found in 1909 by Sundman. The basic ideas behind it and its history are presented. ----- Contrairement à une opinion largement répandue, le problème des trois corps possède une solution analytique. Cette solution fut découverte en 1909 par Sundman. Nous p

E. Klempt

Light-baryon resonances (with u,d, and s quarks in the SU(3) classification) fall on Regge trajectories. When their squared masses are plotted against the intrinsic orbital angular momenta {\rm L}, $Δ^*$'s with even and odd parity can be described by the same Regge trajectory. For a given {\rm L}, nucleon resonances with spin {\rm S}=3/2 are approximatel

A. S. Barabash

All existing "positive" results on two neutrino double beta decay in different nuclei were analyzed. Using procedure recommended by Particle Data Group weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr, $^{100}$Mo, $^{100}$Mo - $^{100}$Ru ($0^+_1$), $^{116}$Cd, $^{150}$Nd and $^{238}$U were obtained. Existing geoche

Ramaz Khomeriki, Stefano Lepri, Stefano Ruffo

We study the dynamics of the "externally" forced and damped Fermi-Pasta-Ulam (FPU) 1D lattice. The forcing has the spatial symmetry of the Fourier mode with wavenumber p and oscillates sinusoidally in time with the frequency omega. When omega is in the phonon band, the p-mode becomes modulationally unstable above a critical forcing, which we determin

Abhijit Borah, Sasanka Ghosh, Sudipta Nandy

The novel inelastic collision properties of two-soliton interaction for an $n$-component coupled higher order nonlinear Schrödinger equation are studied. Some interesting features of three soliton interactions, related to the integrability of the $n$-component coupled higher order nonlinear Schrödinger equation are also discussed.

A. M. Perelomov

The concept of coherent states originally closely related to the nilpotent group of Weyl is generalized to arbitrary Lie group. For the simplest Lie groups the system of coherent states is constructed and its features are investigated.

Victor Snaith

We verify one of Burn's equivariant Tamagawa number conjectures for some families of quaternion fields.

Victor Snaith

When $G$ is abelian and $l$ is a prime we show how elements of the relative K-group $K_{0}({\bf Z}_{l}[G], {\bf Q}_{l})$ give rise to annihilator/Fitting ideal relations of certain associated ${\bf Z}[G]$-modules. Examples of this phenomenon are ubiquitous. Particularly, we give examples in which $G$ is the Galois group of an extension of global fields and t

Stavros Garoufalidis, Martin Loebl

It can be conjectured that the colored Jones function of a knot can be computed in terms of counting paths on the graph of a planar projection of a knot. On the combinatorial level, the colored Jones function can be replaced by its weight system. We give two curious formulas for the weight system of a colored Jones function: one in terms of the permanent of

A. Vershik

We introduce an universum of the Polish (=complete separable metric) space - the convex cone of distance matrices and study its geometry. It happened that the generic Polish spaces in this sense of this universum is so called Urysohn spaces defined by P.S.Urysohn in 20-th, and generic metric triple (= metric space with probability borel measure) is also Urys

Ciro Ciliberto, Margarida Mendes Lopes

In the present note we show that any surface of general type with $p_g=2$,$q=1$ and non-birational bicanonical map has a pencil of curves of genus 2. Combining this result with previous ones, one obtains thatan irregular surface $S$ of general type with $χ(S)\geq 2$ and non-birational bicanonical map has a pencil of curves of genus 2.

Paolo Lisca

The standard contact structure on the three-sphere is invariant under the action of the cyclic group of order p yielding the lens space L(p,q). Therefore, every lens space carries a natural quotient contact structure Q. A theorem of Eliashberg and McDuff classifies the symplectic fillings of (L(p,1), Q) up to diffeomorphism. We announce a generalization of t

C. Dong, G. Mason

We provide a rigorous mathematical foundation to the study of strongly rational, holomorphic vertex operator algebras V of central charge c = 8, 16 and 24 initiated by Schellekens. If c = 8 or 16 we show that V is isomorphic to a lattice theory corresponding to a rank c even, self-dual lattice. If c = 24 we prove, among other things, that either V is isomorp

Volker Runde

We give an example of an amenable, radical Banach algebra, relying on results from non-abelian harmonic analysis due to H. Leptin, D. Poguntke and J. Boidol.

Zhenbo Qin, Weiqiang Wang

Given a closed complex manifold $X$ of even dimension, we develop a systematic (vertex) algebraic approach to study the rational orbifold cohomology rings $\orbsym$ of the symmetric products. We present constructions and establish results on the rings $\orbsym$ including two sets of ring generators, universality and stability, as well as connections with ver

Jason Cantarella, Rob Kusner, John M Sullivan

The ropelength of a knot is the quotient of its length and its thickness, the radius of the largest embedded normal tube around the knot. We prove existence and regularity for ropelength minimizers in any knot or link type; these are $C^{1,1}$ curves, but need not be smoother. We improve the lower bound for the ropelength of a nontrivial knot, and establish

K. S. Stelle

Standard superspace Feynman diagram rules give one estimate of the onset of ultraviolet divergences in supergravity and super Yang-Mills theories. Newer techniques motivated by string theory but which also make essential use of unitarity cutting rules give another in certain cases. We trace the difference to the treatment of higher-dimensional gauge invarian

Patrick Peter, Nelson Pinto-Neto

We construct a simple non singular cosmological model in which the currently observed expansion phase was preceded by a contraction. This is achieved, in the framework of pure general relativity, by means of a radiation fluid and a free scalar field having negative energy. We calculate the power spectrum of the scalar perturbations that are produced in such

H. Kataoka, Hikaru Sato

We construct boundary state and crosscap state in D=4,N=1 type-IIB Z_N orientifold and investigate properties of amplitude. We find that the boundary state of a cylinder is different from the boundary state of a Möbius strip. Using these states, we find that amplitudes do not factorize in Z_N(N=even) orientifold. Tadpole divergence remain in Z_4, Z_8, Z'

Lars Brink

In a preceding report (hep-th/0112261), Pierre Ramond outlined a programme we have followed recently. An important ingredient in a future unique theory for basic physics must be a unique mathematical structure. It is then interesting to investigate the underlying mathematical structure of 11-dimensional space-time. A search for exceptional group structures s

Noel Black

Interactions of charmed and strange mesons with baryonic matter can be calculated in the nonrelativistic quark potential model. For KN scattering data exists, and the theoretical results for S-waves are in approximate agreement with experiment. Here we apply the same model to the scattering of open-charm (D) mesons by nucleons, and give quark model predictio

T. L. Trueman

We use a simple Regge model to determine the energy dependence of the analyzing power for pC scattering in the CNI region. We take the model of Cudell et al which determines the Regge couplings and intercepts for the I=0, non-flip Regge exchanges (Pomeron, f1 and ω) and extend it to the spin-flip amplitudes by allowing each of these exchanges to have indepen

R. D. McKeown, M. J. Ramsey-Musolf

A remarkably successful program of parity-violating electron scattering experiments is providing new insight into the structure of the nucleon. Measurement of the vector form factors enables a definitive study of potential strange quark-antiquark contributions to the electromagnetic structure such as the magnetic moment and charge distribution. Recent experi

Mrinal Dasgupta, Gavin P. Salam

Recently, interest has developed in the distribution of interjet energy flows, with for example the leading-log calculation of the highly non-trivial colour structure of primary emissions in 4-jet systems. Here we point out however that at leading-log level it is insufficient to consider only multiple primary emission from the underlying hard antenna -- addi

Kazuhide Ichikawa, M. Kawasaki

We consider the possibility of the coupling constants of the $SU(3)\times SU(2)\times U(1)$ gauge interactions at the time of big bang nucleosynthesis having taken different values from what we measure at present, and investigate the allowed difference requiring the shift in the coupling constants not violate the successful calculation of the primordial abun

Hee-Jung Lee

The flavor singlet axial charge has been a source of study in the last years due to its relation to the so called {\it Proton Spin Problem}. The relevant flavor singlet axial current is anomalous, i.e., its divergence contains a piece which is the celebrated $U_A(1)$ anomaly. This anomaly is intimately associated with the $η^\prime$ meson, which gets its mas

Savas Dimopoulos, David Elazzar Kaplan

We apply a recently proposed mechanism -- in which an SU(3) symmetry predicts the weak mixing angle -- to construct realistic theories with composite quarks and leptons at a TeV. Although the models are strongly coupled, they are reliably analyzed using complementarity and 't Hooft's anomaly matching. In the simplest models the right-handed fermions

P. O. Bowman, U. M. Heller, A. G. Williams

We report on the lattice quark propagator using standard and improved Staggered quark actions, with the standard, Wilson gauge action. The standard Kogut-Susskind action has errors of \oa{2} while the ``Asqtad'' action has \oa{4}, \oag{2}{2} errors. The quark propagator is interesting for studying the phenomenon of dynamical chiral symmetry breaking and as a

Roger Barlow

A calculator program has been written to give confidence intervals on branching ratios for rare decay modes (or similar quantities) calculated from the number of events observed, the acceptance factor, the background estimate and the associated errors. Results from different experiments (or different channels from the same experiment) can be combined. The ca

M. A. Barker, A. De Santo, P. Dervan, K. Lang

The MINOS long baseline neutrino oscillation experiment is comprised of three calorimeters, a Near Detector at FNAL, a Far Detector at the Soudan mine in northern Minnesota, and a Calibration Detector in a test beam at CERN. The light produced in the interactions of neutrinos in the Near Detector at FNAL will be routed by optical fibres onto the pixels of Ha

R. Burghardt

We embed the Schwarzschild interior solution in a five-dimensional flat space and show that the systems of the interior and the exterior solution are based on the same geometrical principles. It turns out that the energy tensor of the matter has its origin in the five-dimensional structure of the geometry and is built up by the generalized second fundamental

P. C. W. Davies, Adrian C. Ottewill

We study the response of switched particle detectors to static negative energy densities and negative energy fluxes. It is demonstrated how the switching leads to excitation even in the vacuum and how negative energy can lead to a suppression of this excitation. We obtain quantum inequalities on the detection similar to those obtained for the energy density

F. Ya. Khalili

An improved version of the ``optical bar'' intracavity readout scheme for gravitational-wave antennae is considered. We propose to call this scheme ``optical lever'' because it can provide significant gain in the signal displacement of the local mirror similar to the gain which can be obtained using ordinary mechanical lever with unequal arms

S. Carlip

Near an event horizon, the action of general relativity acquires a new asymptotic conformal symmetry. Using two-dimensional dilaton gravity as a test case, I show that this symmetry results in a chiral Virasoro algebra with a calculable classical central charge, and that Cardy's formula for the density of states reproduces the Bekenstein-Hawking entropy.

Yuri Kaluzhny, Daniel Lehmann

We provide a characterization of those nonmonotonic inference operations C for which C(X) may be described as the set of all logical consequences of X together with some set of additional assumptions S(X) that depends anti-monotonically on X (i.e., X is a subset of Y implies that S(Y) is a subset of S(X)). The operations represented are exactly characterized

Daniel Lehmann

The lexicographic closure of any given finite set D of normal defaults is defined. A conditional assertion "if a then b" is in this lexicographic closure if, given the defaults D and the fact a, one would conclude b. The lexicographic closure is essentially a rational extension of D, and of its rational closure, defined in a previous paper. It provid

Ralf Laemmel

We study program refactoring while considering the language or even the programming paradigm as a parameter. We use typed functional programs, namely Haskell programs, as the specification medium for a corresponding refactoring framework. In order to detach ourselves from language syntax, our specifications adhere to the following style. (I) As for primitive

Andrei Komnik, Alexander O. Gogolin

We investigate energy resolved electric current from various correlated host materials under out-of-equilibrium conditions. We find that, due to a combined effect of electron-electron interactions, non-equilibrium and multi-particle tunnelling, the energy resolved current is finite even above the Fermi edge of the host material. In most cases, the current de

E. Korutcheva, V. Del Prete

In a recent work we have introduced a novel approach to study the effect of weak non-linearities in the transfer function on the information transmitted by an analogue channel, by means of a perturbative diagrammatic expansion. We extend here the analysis to all orders in perturbation theory, which allows us to release any constraint concerning the magnitude

R. Combescot, C. Mora

We explore analytically the nature of the transition to the Fulde-Ferrel-Larkin-Ovchinnikov superfluid phases in the vicinity of the tricritical point, where these phases begin to appear. We make use of an expansion of the free energy up to an overall sixth order, both in order parameter amplitude and in wavevector. We first explore the minimization of this

H. Rosner, J. M. An, W. E. Pickett, S. -L. Drechsler

We provide a comparison of accurate full potential band calculations of the Fermi surfaces areas and masses of MgB2 and ZrB2 with the de Haas-van Alphen date of Yelland et al. and Tanaka et al., respectively. The discrepancies in areas in MgB2 can be removed by a shift of sigma-bands downward with respect to pi-bands by 0.24 eV. Comparison of effective masse

P. Vignolo, M. L. Chiofalo, S. Succi, M. P. Tosi

We present a new numerical method for studying the dynamics of quantum fluids composed of a Bose-Einstein condensate and a cloud of bosonic or fermionic atoms in a mean-field approximation. It combines an explicit time-marching algorithm, previously developed for Bose-Einstein condensates in a harmonic or optical-lattice potential, with a particle-in-cell Mo

H. Appel, E. K. U. Gross, K. Burke

An approximate solution to the time-dependent density functional theory (TDDFT) response equations for finite systems is developed, yielding corrections to the single-pole approximation. These explain why allowed Kohn-Sham transition frequencies and oscillator strengths are usually good approximations to the true values, and why sometimes they are not. The a

Z. Akdeniz, A. Minguzzi, P. Vignolo, M. P. Tosi

We use a semiclassical three-fluid thermodynamic model to evaluate the phenomena of spatial demixing in mesoscopic clouds of fermionic and bosonic atoms at high dilution under harmonic confinement, assuming repulsive boson-boson and boson-fermion interactions and including account of a bosonic thermal cloud at finite temperature T. The finite system size all

Hidekazu Morita, Shinji Watanabe, Masatoshi Imada

We study phase diagrams of the Hubbard model on anisotropic triangular lattices, which also represents a model for $κ$-type BEDT-TTF compounds. In contrast with mean-field predictions, path-integral renormalization group calculations show a universal presence of nonmagnetic insulator sandwitched by antiferromagnetic insulator and paramagnetic metals. The non

F. Cordero, C. R. Grandini, M. Ferretti

The complex dynamic Young's modulus of ceramic Nd2-xCexCuO4 with x = 0, 0.05 and 0.20 has been measured from 1.5 to 100 K at frequencies of 1-10 kHz. In the undoped sample the modulus starts decreasing below ~20 K, instead of approaching a constant value as in a normal solid. The modulus minimum has been interpreted in terms of paraelastic contribution f

S. Jonsell, H. Heiselberg, C. J. Pethick

We calculate energy levels of two and three bosons trapped in a harmonic oscillator potential with oscillator length $a_{\mathrm osc}$. The atoms are assumed to interact through a short-range potential with a scattering length $a$, and the short-distance behavior of the three-body wave function is characterized by a parameter $θ$. For large positive $a/a_{\m

Julien Barre, Freddy Bouchet, Thierry Dauxois, Stefano Ruffo

We study an analytically tractable model with long-range interactions for which an out-of-equilibrium very long-lived coherent structure spontaneously appears. The dynamics of this model is indeed very peculiar: a bicluster forms at low energy and is stable for very long time, contrary to statistical mechanics predictions. We first explain the onset of the s

S. Cocco, R. Monasson

A large deviation analysis of the solving complexity of random 3-Satisfiability instances slightly below threshold is presented. While finding a solution for such instances demands an exponential effort with high probability, we show that an exponentially small fraction of resolutions require a computation scaling linearly in the size of the instance only. T

Wolfgang Kinzel, Ido Kanter

Two neural networks which are trained on their mutual output bits are analysed using methods of statistical physics. The exact solution of the dynamics of the two weight vectors shows a novel phenomenon: The networks synchronize to a state with identical time dependent weights. Extending the models to multilayer networks with discrete weights, it is shown ho

Huan-Qiang Zhou, Jon Links, Ross H. McKenzie, Xi-Wen Guan

A model describing coherent quantum tunneling between two trapped Bose-Einstein condensates is shown to admit an exact solution. The spectrum is obtained by the algebraic Bethe ansatz. An asymptotic analysis of the Bethe ansatz equations leads us to explicit expressions for the energies of the ground and first excited states in the limit of {\it weak} tunnel

K. W. Yu

We have employed our recently developed Green's function formalism to study the dielectric behavior of a model membrane, formed by two periodic interfaces separating two media of different dielectric constants. The Maxwell's equations are converted into a surface integral equation; thus it greatly simplifies the solutions and yields accurate results

Qijin Chen, Ying-Jer Kao, Andrew P. Iyengar, K. Levin

We study the sensitivity of $T_c$ and the pseudogap onset temperature, $T^*$, to low fields, $H$, for cuprate superconductors, using a BCS-based approach extended to arbitrary coupling. We find that $T^*$ and $T_c$, which are of the same superconducting origin, have very different $H$ dependences. The small coherence length makes $T^*$ rather insensitive to

J. A. Méndez-Bermúdez, G. A. Luna-Acosta, P. Šeba, K. N. Pichugin

We study classical and quantum scattering properties in the ballistic regime of particles in two-dimensional chaotic billiards that are models of electron- or micro- waveguides. To this end we construct the purely classical counterparts of the Scattering Probability (SP) matrix $\mid S_{n,m}\mid^2$ and Husimi distributions and specialize to the case of mixed

Takafumi Kita

This paper derives a density matrix of the steady-state statistical mechanics compatible with the steady-state thermodynamics proposed by Oono and Paniconi [Prog. Theor. Phys. Suppl. {\bf 130}, 29 (1998)]. To this end, we adopt three plausible basic assumptions for uniform steady states: (i) equivalence between any two subsystems of the total, (ii) statistic

C. Morisset, D. Schaerer, N. -L. Martin-Hernandez, E. Peeters

We present a detailed photoionization model of G29.96-0.02 (hereafter G29.96), one of the brightest Galactic Ultra Compact HII (UCHII) regions in the Galaxy. This source has been observed extensively at radio and infrared wavelengths. The most recent data include a complete ISO (SWS and LWS) spectrum, which displays a remarkable richness in atomic fine-struc

Shinae Park, Scott J. Kenyon

We describe near-IR imaging data for a sample of 23 class I sources in the Taurus-Auriga dark clouds. Combining our data with previous photometry, we detect brightness variations of 0.1-0.5 mag in many sources. The near-IR morphologies are consistent with mm continuum measurements. Most (60%) of the sample are true protostars; the rest may be objects in tran

G. Fasano, D. Bettoni, M. D'Onofrio, P. Kjaergaard

This is the first paper of a series investigating the scaling relations of early-type galaxies in clusters. Here we illustrate the multi-band imagery and the image reduction and calibration procedures relative to the whole sample of 22 clusters at 0.05 < z < 0.25. We also present the detailed surface photometry of 312 early-type galaxies in 7 clusters in the

E. Olsson, C. J. Pethick

The study of tensor correlations and pions in dense matter in astronomical contexts has recently acquired renewed importance for a number of reasons. One is the discovery by Akmal, and Pandharipande (Phys. Rev. C56 2261 (1997)) of a striking increase in tensor correlations in cold matter at densities not far above that of isospin-symmetric nuclear matter at

H. Beuther, P. Schilke, F. Gueth, M. McCaughrean

We present a high-angular-resolution molecular line and millimeter continuum study of the massive star formation site IRAS 05358+3543. The most remarkable feature is a highly collimated (collimation factor ~10) and massive (>10 M_sun) bipolar outflow of 1 pc length, which is part of a quadrupolar outflow system. The three observed molecular outflows forming

Zsolt Paragi

A radio &#34;colour-colour&#34; diagram is defined in order to determine the evolutionary state of synchrotron-emitting plasma bubbles that are ejected during outbursts in microquasars. We establish the colour-colour diagram for the plasmons of SS433 observed on 18 April 1998 using VLBI observations. We show that the radio plasmons are not consistent with a

Y. Ascasibar, G. Yepes, S. Gottloeber, V. Mueller

The cosmic star formation history in Cold Dark Matter dominated cosmological scenarios is studied by means of hydrodynamical numerical simulations. In particular, we explore a low density model with a Lambda-term and two high density models with different power spectra, all of them being spatially flat. Our simulations employ a fully nonlinear N-body and Eul

Jin H. An, Cheongho Han

In this paper, we investigate the effect of a wide binary companion of the lens on the astrometric behavior of Galactic gravitational microlensing events and compare it to the effect on the photometric behavior. We find that the wide binary companion of the lens can affect the centroid motion of images substantially even if the corresponding light curve appe

Yuichi Terashima, Naoko Iyomoto, Luis C. Ho, Andrew F. Ptak

This paper presents a comprehensive study of the X-ray properties of low-ionization nuclear emission-line regions (LINERs) and low-luminosity Seyfert galaxies based on observations obtained with ASCA. We analyzed data of 53 observations of 21 LINERs and 17 low-luminosity Seyferts. X-ray emission has been detected in all but one object. The X-ray luminosities