January 2003 arXiv papers — page 16

Marta Gomez-Reino

In this paper we analyse the non-hyperelliptic Seiberg-Witten curves derived from M-theory that encode the low energy solution of N=2 supersymmetric theories with product gauge groups. We consider the case of a SU(N_1)xSU(N_2) gauge theory with a hypermultiplet in the bifundamental representation together with matter in the fundamental representations of SU(

J. Smiseth, E. Smoergrav, F. S. Nogueira, J. Hove

Large-scale Monte Carlo simulations are employed to study phase transitions in the three-dimensional compact abelian Higgs model in adjoint representations of the matter field, labelled by an integer q, for q=2,3,4,5. We also study various limiting cases of the model, such as the $Z_q$ lattice gauge theory, dual to the $3DZ_q$ spin model, and the 3DXY spin m

Ari Pakman

The unitarity of the NS supersymmetric coset SL(2,R)/U(1) is studied for the discrete representations. The results are applied to the proof of the no-ghost theorem for fermionic strings in AdS(3) x N in the NS sector. A no-ghost theorem is proved for states in flowed discrete representations.

Maciej Dunajski, Lionel J. Mason

We briefly review the hierarchy for the hyper-Kähler equations and define a notion of symmetry for solutions of this hierarchy. A four-dimensional hyper-Kähler metric admits a hidden symmetry if it embeds into a hierarchy with a symmetry. It is shown that a hyper-Kähler metric admits a hidden symmetry if it admits a certain Killing spinor. We show that if th

A. Pautrat, C. Goupil, Ch. Simon, D. Charalambous

We report Small-Angle Neutron Scattering (SANS) measurements on the vortex lattice in a PbIn polycrystal in the presence of an applied current. Using the rocking curves as a probe of the distribution of current in the sample, we observe that vortex pinning is due to the surface roughness. This leads to a surface current that persists in the flux flow region.

M. Xu, F. Stefani, G. Gerbeth

With only a few exceptions, the numerical simulation of cosmic and laboratory hydromagnetic dynamos has been carried out in the framework of the differential equation method. However, the integral equation method is known to provide robust and accurate tools for the numerical solution of many problems in other fields of physics. The paper is intended to faci

Arnab Chatterjee, Bikas K. Chakrabarti, S. S. Manna

We have numerically simulated the ideal-gas models of trading markets, where each agent is identified with a gas molecule and each trading as an elastic or money-conserving two-body collision. Unlike in the ideal gas, we introduce (quenched) saving propensity of the agents, distributed widely between the agents ($0 \le λ< 1$). The system remarkably self-orga

Jinsung Park, Krzysztof P. Wojciechowski

We prove an adiabatic decomposition formula of the zeta-determinant of the Laplace type operator with respect to Dirichlet boundary condition. We allow the non-invertible tangential operator. As a result, our adiabatic decomposition formula involves the scattering matrix over the manifold with cylindrical end. We also describe the adiabatic limit of the zeta

A. B. Arbuzov

Radiative corrections to the muon decay spectrum due to soft and virtual electron--positron pairs are calculated.

Roman Lietava, Jan Pisut, Neva Pisutova, Boris Tomasik

We propose a simple Glauber-type mechanism for suppression of jet production up to transverse momenta of about 10 GeV/c at RHIC. For processes in this kinematic region, the formation time is smaller than the interval between two successive hard partonic collisions and the subsequent collision influences the jet production. Number of jets then roughly scales

R. Skibinski, J. Golak, H. Witala, W. Glockle

The three-nucleon photodisintegration of 3He has been calculated in the whole phase space using consistent Faddeev equations for the three-nucleon bound and scattering states. Modern nucleon-nucleon and 3N forces have been applied as well as different approaches to nuclear currents. Phase space regions are localized where 3N force effects are especially larg

Roberto Iengo, Jorge G. Russo

We study the classical breaking of a highly excited (closed or open) string state on the leading Regge trajectory, represented by a rotating soliton solution, and we find the resulting solutions for the outgoing two pieces, describing two specific excited string states. This classical picture reproduces very accurately the precise analytical relation of the

Ion I. Cotăescu, Mihai Visinescu

The continuous and discrete symmetries of the Dirac-type operators produced by particular Killing-Yano tensors are studied in manifolds of arbitrary dimensions. The Killing-Yano tensors considered are covariantly constant and realize certain square roots of the metric tensor. Such a Killing-Yano tensor produces simultaneously a Dirac-type operator and the ge

V. N. Yershov

It is supposed that the electron neutrino mass is related to the structures and masses of the $W^\pm$ and $Z^0$ bosons. Using a composite model of fermions (described elsewhere), it is shown that the massless neutrino is not consistent with the high values of the experimental masses of $W^\pm$ and $Z^0$. Consistency can be achieved on the assumption that the

Juan P. Garrahan, David Chandler

We introduce a coarse-grained model for atomic glass formers. Its elements are physically motivated local microscopic dynamical rules parameterized by observables. Results of the model are established and used to interpret the measured behaviors of supercooled fluids approaching glass transitions. The model predicts the presence of a crossover from hierarchi

O. B. Karpov

General relativistic spin-orbit interaction leads to the quasiresonant oscillation of the gyroscope mass center along the orbital normal. The beating amplitude does not include the speed of light and equals the ratio of the intrinsic momentum of the gyroscope to its orbital momentum. The modulation frequency equals the angular velocity of the geodetic preces

P. Danielewicz

Binding energy of symmetric nuclear matter can be accessed straightforwardly with the textbook mass-formula and a sample of nuclear masses. We show that, with a minimally modified formula (along the lines of the droplet model), the symmetry energy of nuclear matter can be accessed nearly as easily. Elementary considerations for a macroscopic nucleus show tha

Hideyuki Umeda, Ken&#39;ichi Nomoto

It has been proposed theoretically that the first generation of stars in the Universe (population III) would be as massive as 100 solar masses (100Mo), because of inefficient cooling of the precursor gas clouds. Recently, the most iron-deficient (but still carbon-rich) low-mass star -- HE0107-5240 -- was discovered. If this is a population III that gained it

H. Tajima, H. Aihara, T. Higuchi, H. Kawai

The proper-time resolution function for the measurement of the time evolution of B mesons with the Belle detector at KEKB is studied in detail. The obtained resolution function is applied to the measurement of B meson lifetimes, the B0-B0bar oscillation frequency and time-dependent CP asymmetries.

Andrew W. Kerr, John C. Hauck, Bahram Mashhoon

We discuss the influence of the cosmological constant on the gravitomagnetic clock effect and the gravitational time delay of electromagnetic rays. Moreover, we consider the relative motion of a binary system to linear order in the cosmological constant $Λ$. The general expression for the effect of $Λ$ on pericenter precession is given for arbitrary orbital

A. I. Zenchuk

The paper represents the method for construction of the families of particular solutions to some new classes of $(n+1)$ dimensional nonlinear Partial Differential Equations (PDE). Method is based on the specific link between algebraic matrix equations and PDE. Admittable solutions depend on arbitrary functions of $n$ variables.

Tomotsugu Goto, Sadanori Okamura, Maki Sekiguchi, Mariangela Bernardi

In previous work on galaxy clusters, several authors reported a discovery of an unusual population of galaxies, which have spiral morphologies, but do not show any star formation activity. These galaxies are called ``passive spirals&#39;&#39;, and have been interesting since it has been difficult to understand the existence of such galaxies. Using a volume l

P. J. Lin-Chung

A general method in constructing a complete set of wave functions for multipartite identical qubits is presented based on the irreducible representations of the permutation group and the nth rank tensors. Particular examples for n =2, 3, and 4 are derived and the entanglement behavior for each state is examined from several criteria. It is found that the sta

H. Kleinert, A. Chervyakov

The partition function of a quantum statistical system in flat space can always be written as an integral over a classical Boltzmann factor $\exp[ -βV^{\rm eff cl({\bf x}_0)]$, where $V^{\rm eff cl({\bf x}_0)$ is the so-called effective classical potential containing the effects of all quantum fluctuations. The variable of integration is the temporal path av

C. Henkel, J. -Y. Courtois, R. Kaiser, C. Westbrook

A detailed theoretical investigation of the reflection of an atomic de Broglie wave at an evanescent wave mirror is presented. The classical and the semiclassical descriptions of the reflection process are reviewed, and a full wave-mechanical approach based on the analytical soution of the corresponding Schrödinger equation is presented. The phase shift at r

C. Lavor, L. R. U. Manssur, R. Portugal

We review Grover&#39;s algorithm by means of a detailed geometrical interpretation and a worked out example. Some basic concepts of Quantum Mechanics and quantum circuits are also reviewed. This work is intended for non-specialists which have basic knowledge on undergraduate Linear Algebra.

Andreas Klappenecker, Martin Roetteler

Unitary error bases generalize the Pauli matrices to higher dimensional systems. Two basic constructions of unitary error bases are known: An algebraic construction by Knill, which yields nice error bases, and a combinatorial construction by Werner, which yields shift-and-multiply bases. An open problem posed by Schlingemann and Werner (see http://www.imaph.

L. R. U. Manssur, R. Portugal

We simulate Grover&#39;s algorithm in a classical computer by means of a stochastic method using the Hubbard-Stratonovich decomposition of n-qubit gates into one-qubit gates integrated over auxiliary fields. The problem reduces to finding the fixed points of the associated system of Langevin differential equations. The equations are obtained automatically fo

Alonso Botero, Benni Reznik

We address the decomposition of a multi-mode pure Gaussian state with respect to a bi-partite division of the modes. For any such division the state can always be expressed as a product state involving entangled two-mode squeezed states and single mode local states at each side. The character of entanglement of the state can therefore be understood modewise;

P. M. Bellan

It is shown that if a current-carrying magnetic flux tube is bulged at its axial midpoint z=0 and constricted at its axial endpoints z=+h,-h, then plasma will be accelerated from z=+h,-h towards z=0 resulting in a situation similar to two water jets pointed at each other. The ingested plasma convects embedded, frozen-in toroidal magnetic flux from z=+h,-h to

S. Frauendorf, N. K. Kuzmenko, V. M. Mikhajlov, J. Sheikh

The pair correlations in mesoscopic systems such as $nm$-size superconducting clusters and nuclei are studied at finite temperature for the canonical ensemble of fermions in model spaces with a fixed particle number: i) a degenerate spherical shell (strong coupling limit), ii) an equidistantly spaced deformed shell (weak coupling limit). It is shown that aft

Jean-Jacques Zondy

Steady-state and dynamics of the self-phase-locked (3ω==> 2ω, ω) subharmonic optical parametric oscillator are analyzed in the pump-and-signal resonant configuration, using an approximate analytical model and a full propagation model. The upper branch solutions are found always stable, regardless of the degree of pump enhancement. The domain of existence of

Lior M. Burko

We consider the period of a simple pendulum in the gravitational field of the spherical Earth. Effectively, gravity is enhanced compared with the often used flat Earth approximation, such that the period of the pendulum is shortened. We discuss the flat Earth approximation, and show when the corrections due to the spherical Earth may be of interest.

L. Roca, E. Oset

A theoretical analysis of the $(π^-,γγ)$ reaction in nuclei is made in order to find the viability of this reaction to test modifications of the $σ$ meson mass in nuclear matter. The $ππ$ correlation in the scalar-isoscalar channel in nuclear matter could, in principle, manifest itself in this reaction since it plays an important role in the $ππ\toγγ$ mechan

Kazuhiro Yabana, Manabu Ueda, Takashi Nakatsukasa

The fusion reaction of a halo nucleus 11Be on 208Pb is described by a three-body direct reaction model. A time-dependent wave packet approach is applied to a three-body reaction problem. The wave packet approach enables us to obtain scattering solutions without considering the three-body scattering boundary conditions. The time evolution of the wave packet a

FOPI Collaboration, A. Andronic

We present new experimental data on directed flow in collisions of Au+Au, Xe+CsI and Ni+Ni at incident energies from 90 to 400A MeV. We study the centrality and system dependence of integral and differential directed flow for particles selected according to charge. All the features of the experimental data are compared with Isospin Quantum Molecular Dynamics

Tibor Toth-Katona, John R. Cressman, Walter I. Goldburg, James T. Gleeson

This is a study of the global fluctuations in power dissipation and light transmission through a liquid crystal just above the onset of electroconvection. The source of the fluctuations is found to be the creation and annihilation of defects. They are spatially uncorrelated and yet temporally correlated. The temporal correlation is seen to persist for extrem

Giuliano Benenti, Giulio Casati, Gregor Veble

We study in detail the time behavior of classical fidelity for chaotic systems. We show in particular that the asymptotic decay, depending on system dynamical properties, can be either exponential, with a rate determined by the gap in the discretized Perron-Frobenius operator, or algebraic, with the same power as for correlation functions decay. Therefore th

Qi Cheng

In this paper, a random primality proving algorithm is proposed, which generates prime certificate of length O(log n). The certificate can be verified in deterministic time O(log^4 n). The algorithm runs in heuristical time tilde{O}(log^4 n), some supporting evidences are provided.

J. Taback, K. Whyte

We study the large scale geometry of the upper triangular subgroup of PSL(2,Z[1/n]), which arises naturally in a geometric context. We prove a quasi-isometry classification theorem and show that these groups are quasi-isometrically rigid with infinite dimensional quasi-isometry group. We generalize our results to a larger class of groups which are metabelian

Francois Bouchut, Francois Golse, Christophe Pallard

R. Glassey and W. Strauss have proved in [Arch. Rational Mech. Anal. 92 (1986), 59--90] that classical solutions to the relativistic Vlasov-Maxwell system in three space dimensions do not develop singularities as long as the support of the distribution function in the momentum variable remains bounded. The present paper simplifies their proof.

E. Chetcuti, P. Ptak

Suppose that $S$ is an incomplete inner product space. A. Dvurečenskij shows that there are no finitely additive states on orthogonally closed subspaces, $F(S)$, of $S$ that are regular with respect to finitely dimensional spaces. In this note we show that the most important special case of the former result--the case of the evaluations given by vectors in t

Roland Berger

It has been shown recently, in a joint work with Michel Dubois-Violette and Marc Wambst (see math.QA/0203035), that Koszul property of $N$-homogeneous algebras (as defined in the original paper) becomes natural in a $N$-complex setting. A basic question is to define the differential of the bimodule Koszul complex of an $N$-homogeneous algebra, e.g., for comp

River Chiang

We consider compact connected six dimensional symplectic manifolds with Hamiltonian SU(2) or SO(3) actions with cyclic principal stabilizers. We classify such manifolds up to equivariant symplectomorphisms.

A. A. Vladimirov

We consider an operator function (F(λ)) for (λ\in(σ,τ)\subseteq\mathbb R) whose values are semibounded selfadjoint operators in Hilbert space (\mathfrak H). Our main goal is to estimate the number (\mathcal N_F(α,β)) of the eigenvalues of (F(λ)) on a segment ([α,β)\Subset(σ,τ)). In particular, we prove the estimates (\mathcal N_F(α,β)\geqslant ν_F(β)-ν_F(α))

A. Losev, Yu. Manin

This paper is a sequel to [LoMa] where moduli spaces of painted stable curves were introduced and studied. We define the extended modular operad of genus zero, algebras over this operad, and study the formal differential geometric structures related to these algebras: pencils of flat connections and Frobenius manifolds without metric. We focus here on the co

Yuri G. Zarhin

We discuss a certain class of absolutely irreducible group representations that behave nicely under the restriction to normal subgroups and subalgebras. These representations proved to be useful for the construction of abelian varieties with small endomorphism rings.

G. W. Gibbons

After a pedagogical review of elementary cosmology, I go on to discuss some obstacles to obtaining inflationary or accelerating universes in M/String Theory. In particular, I give an account of an old No-Go Theorem to this effect. I then describe some recent ideas about the possible rôle of the tachyon in cosmology. I stress that there are many objections to

Marko Kolanovic

I consider gravity induced over a smooth (finite thickness) soliton. Graviton kinetic term is coupled to bulk scalar that develops solitonic vacuum expectation value. Couplings of Kaluza-Klein modes to soliton-localized matter are suppressed, giving rise to crossover distance $r_c=M_{P}^2/M_{*}^3$ between 4D and 5D behavior. This system can be viewed as a fi

Giuseppe Bimonte, Giampiero Esposito, Giuseppe Marmo, Cosimo Stornaiolo

Peierls brackets are part of the space-time approach to quantum field theory, and provide a Poisson bracket which, being defined for pairs of observables which are group invariant, is group invariant by construction. It is therefore well suited for combining the use of Poisson brackets and the full diffeomorphism group in general relativity. The present pape

Ali H. Chamseddine

Various approaches by the author and collaborators to define gravitational fluctuations associated with a noncommutative space are reviewed.

G. Morchio, F. Strocchi

The convergence of integrals over charge densities is discussed in relation with the problem of electric charge and (non-local) charged states in Quantum Electrodynamics (QED). Delicate, but physically relevant, mathematical points like the domain dependence of local charges as quadratic forms and the time smearing needed for strong convergence of integrals

Bert Schroer

Modular theory of operator algebras and the associated KMS property are used to obtain a unified description for the thermal aspects of the standard heat bath situation and those caused by quantum vacuum fluctuations from localization. An algebraic variant of lightfront holography reveals that the vacuum polarization on wedge horizons is compressed into the

Thomas A. Trainor

The balance function has been proposed to `clock&#39; hadronization by measuring the charge-dependent correlation length on rapidity. According to the proposal a narrowed balance function would imply reduced hadron diffusion time and therefore delayed hadronization due to a long-lived prehadronic state, a quark-gluon plasma or QGP. I examine this chain of ar

M. N. Rebelo

Fermion masses and mixing, both in the quark and leptonic sector, are discussed within the approach to the Yukawa puzzle proposed by Arkani-Hamed and Schmaltz. In the quark sector we have shown that at least two extra dimensions are necessary in order to obtain sufficient CP violation, while reproducing the correct quark mass spectrum and mixing angles. We h

Sz. Borsanyi, A. Patkos, D. Sexty

We study the onset of Goldstone phenomenon in a hybrid inflation scenario. The physically motivated range of parameters is analyzed in order to meet the cosmological constraints. Classical equations of motion are solved and the evolution through the spontaneous symmetry breaking is followed. We emphasize the role of topological defects that partially maintai

Orhan Cakir

The single production of top quark due to flavor changing neutral current (FCNC) interaction and its decay to bW are studied at CLIC+LHC based gamma-p colliders. We consider both t-c-gamma and t-u-gamma anomalous couplings. The anomalous charm (up) quark anomalous coupling parameter kappa_gamma^c (kappa_gamma^u) can be probed down to 9.5x10^-3 (8.0x10^-3) at

D. Janc, M. Rosina, D. Treleani, A. Del Fabbro

In the LHC collider a significant rate of events with double parton scattering is expected. This will be the leading mechanism for production of two b-bbar pairs. We estimate the probability of binding two b quarks into a diquark and the probability of dressing this diquark into a b-b-ubar-dbar ISP=01+ tetraquark. Calculations shows that that this bound stat

Daniel Ashery, H. C. Pauli

We use the transverse-momentum dependence of the cross section for diffractive dissociation of high energy pions to two jets to study some non-perturbative Light-Cone wave functions of the pion. We compare the predictions for this distribution by Gaussian and Coulomb wave functions as well as the wave function derived from solution of the Light-Cone Hamilton

S. M. Troshin, N. E. Tyurin

We discuss recent HERA results on vector--meson electroproduction gamma*p -> Vp and demonstrate that universality of the initial and final state interactions responsible for the transition between the on- and off-mass shell states allows to explain energy independence of the ratio of exclusive rho electroproduction cross section to the total cross section. W

G. Akemann, T. Wettig

We apply a complex chiral random matrix model as an effective model to QCD with a small chemical potential at zero temperature. In our model the correlation functions of complex eigenvalues can be determined analytically in two different limits, at weak and strong non-Hermiticity. We compare them to the distribution of the smallest Dirac operator eigenvalues

Sven Holtmann, Thomas Schulze

We numerically investigate the three-dimensional O(6) model on 12^3 to 120^3 lattices. From Binder&#39;s cumulant at vanishing magnetic field we obtain the critical coupling J_c=1.42865(5) and verify this value with the χ^2-method. The universal value of Binder&#39;s cumulant at this point is g_r(J_c)=-1.94456(10). At the critical coupling we find the critic

T. B. Humensky

SLAC E-158 is making the first measurement of parity violation in Moller scattering. E-158 measures the right-left cross-section asymmetry, A_LR, in the scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of ~10^-7 to an accuracy of better than 10^-

CLEO Collaboration, S. E. Csorna

Using 9.1 fb-1 of e+ e- data collected at the Upsilon(4S) with the CLEO detector using the Cornell Electron Storage Ring, measurements are reported for both the branching fractions and the helicity amplitudes for the decays B- -> D*0 rho- and B0bar -> D*+ rho-. The fraction of longitudinal polarization in B0bar -> D*+ rho- is found to be consistent with that

L3 Collaboration

The three different helicity states of W bosons produced in the reaction e+ e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bos

Ariel Caticha

Can the spatial distance between two identical particles be explained in terms of the extent that one can be distinguished from the other? Is the geometry of space a macroscopic manifestation of an underlying microscopic statistical structure? Is geometrodynamics derivable from general principles of inductive inference? Tentative answers are suggested by a m

G. Lambiase

Bounds on the scale parameter {\cal L} arising in loop quantum gravity theory are derived in the framework of Cerenkov&#39;s effect and neutrino oscillations. Assuming that {\cal L} is an universal constant, we infer {\cal L}> 10^{-18}eV^{-1}, a bound compatible with ones inferred in different physical context.

Peter Buergisser, Martin Lotz

We prove lower bounds of order $n\log n$ for both the problem to multiply polynomials of degree $n$, and to divide polynomials with remainder, in the model of bounded coefficient arithmetic circuits over the complex numbers. These lower bounds are optimal up to order of magnitude. The proof uses a recent idea of R. Raz [Proc. 34th STOC 2002] proposed for mat

Giorgio Parisi

In this note we study the convergence of the survey decimation algorithm. An analytic formula for the reduction of the complexity during the decimation is derived. The limit of the converge of the algorithm are estimated in the random case: interesting phenomena appear near the boundary of convergence.

Marcus Hutter

The probability of observing $x_t$ at time $t$, given past observations $x_1...x_{t-1}$ can be computed with Bayes&#39; rule if the true generating distribution $μ$ of the sequences $x_1x_2x_3...$ is known. If $μ$ is unknown, but known to belong to a class $M$ one can base ones prediction on the Bayes mix $ξ$ defined as a weighted sum of distributions $ν\in

S. M. Kautz

A bounded Kolmogorov-Loveland selection rule is an adaptive strategy for recursively selecting a subsequence of an infinite binary sequence; such a subsequence may be interpreted as the query sequence of a time-bounded Turing machine. In this paper we show that if A is an algorithmically random sequence, A_0 is selected from A via a bounded Kolmogorov-Lovela

Kewen Wang, Lizhu Zhou

Much work has been done on extending the well-founded semantics to general disjunctive logic programs and various approaches have been proposed. However, these semantics are different from each other and no consensus is reached about which semantics is the most intended. In this paper we look at disjunctive well-founded reasoning from different angles. We sh

A. Rochefort

We theoretically studied the electronic and electrical properties of metallic and semiconducting peapods with encapsulated C_{60} (C_{60}@CNT) as a function of the carbon nanotube (CNT) diameter. For exothermic peapods (CNT diameter > 11.8 A), only minor changes, ascribed to a small structural deformation of the nanotube walls, were observed. These include a

Constantino Tsallis, Celia Anteneodo, Lisa Borland, Roberto Osorio

Ergodicity, this is to say, dynamics whose time averages coincide with ensemble averages, naturally leads to Boltzmann-Gibbs (BG) statistical mechanics, hence to standard thermodynamics. This formalism has been at the basis of an enormous success in describing, among others, the particular stationary state corresponding to thermal equilibrium. There are, how

Steven S. Plotkin, Peter G. Wolynes

The energy landscapes of proteins have evolved to be different from most random heteropolymers. Many studies have concluded that evolutionary selection for rapid and reliable folding to a given structure that is stable at biological temperatures leads to energy landscapes having a single dominant basin and an overall funnel topography. We show here that, whi

Joseph Rudnick, Robijn Bruinsma

Recent studies reveal that certain viruses package a portion of their genome in a manner that mirrors the icosahedral symmetry of the protein container, or capsid. Graph theoretical constraints forbid exact realization of icosahedral symmetry. This paper proposes a model for the determination of quasi-icosahedral genome structures and discusses the connectio

A. M. C. Souza, C. Tsallis

The Boltzmann-Gibbs celebrated entropy $S_{BG}=-k\sum_ip_i \ln p_i$ is {\it concave} (with regard to all probability distributions $\{p_i\}$) and {\it stable} (under arbitrarily small deformations of any given probability distribution). It seems reasonable to consider these two properties as {\it necessary} for an entropic form to be a {\it physical} one in

Hwayong Noh, M. P. Lilly, D. C. Tsui, J. A. Simmons

The conductivity of extremely high mobility dilute two-dimensional holes in GaAs changes linearly with temperature in the insulating side of the metal-insulator transition. Hopping conduction, characterized by an exponentially decreasing conductivity with decreasing temperature, is not observed when the conductivity is smaller than $e^{2}/h$. We suggest that

A. V. Malyshev, V. A. Malyshev, F. Dominguez-Adame

We study theoretically diffusion of one-dimensional Frenkel excitons in J-aggregates at temperatures that are smaller or of the order of the J-band width. We consider an aggregate as an open linear chain with uncorrelated on-site (diagonal) disorder that localizes the exciton at chain segments of size smaller than the full chain length. The exciton diffusion

L. I. Salminen, A. I. Tolvanen, M. J. Alava

We report tensile failure experiments on paper sheets. The acoustic emission energy and the waiting times between acoustic events follow power-law distributions. This remains true while the strain rate is varied by more than two orders of magnitude. The energy statistics has the exponent $β\sim 1.25 \pm 0.10$ and the waiting times the exponent $τ\sim 1.0 \pm

Alexander Weiße, Jan Loos, Holger Fehske

In view of recent experiments, indicating the spatial coexistence of conducting and insulating regions in the ferromagnetic metallic phase of doped manganites, we propose a refined mixed-phase description. The model is based on the competition of a double-exchange driven metallic component and a polaronic insulating component, whose volume fractions and carr

Eldon G. Emberly, George Kirczenow

Ab-initio total energy calculations reveal benzene-dithiolate (BDT) molecules on a gold surface, contacted by a monoatomic gold STM tip to have two classes of low energy conformations with differing symmetries. Lateral motion of the tip or excitation of the molecule cause it to change from one conformation class to the other and to switch between a strongly

Stefano Luin, Vittorio Pellegrini, Aron Pinczuk, Brian S. Dennis

Inelastic light scattering measurements of low-lying collective excitations of electron double layers in the quantum Hall state at total filling nu_T=1 reveal a deep magnetoroton in the dispersion of charge-density excitations across the tunneling gap. The roton softens and sharpens markedly when the phase boundary for transitions to highly correlated compre

R. Monaco, R. J. Rivers

It has been argued by Zurek and Kibble that the likelihood of producing defects in a continuous phase transition depends in a characteristic way on the quench rate. In this paper we discuss our experiment for measuring the Zurek-Kibble scaling exponent $σ$ for the production of fluxons in annular symmetric Josephson Tunnel Junctions. The predicted exponent i

Xavier Waintal, Michel Viret

We consider the spin torque induced by a current flowing ballistically through a magnetic domain wall. In addition to a global pressure in the direction of the electronic flow, the torque has an internal structure of comparable magnitude due to the precession of the electrons&#39; spins at the &#34;Larmor&#34; frequency. As a result, the profile of the domai

Michel Droz, Antonio L. Ferreira, Adam Lipowski

Recently some two-dimensional models with double symmetric absorbing states were shown to share the same critical behaviour that was called the voter universality class. We show, that for an absorbing-states Potts model with finite but further than nearest neighbour range of interactions the critical point is splitted into two critical points: one of the Isi

Qingshan Yuan, Peter Thalmeier

The s+g mixed gap function Δ_k=Δ{[(1-x)-x\sin^4θ\cos4ϕ]} (x: weight of g-wave component) has been studied within BCS theory. By suitable consideration of the pairing interaction, we have confirmed that the coexistence of s- and g-wave, as well as the state with equal s and g amplitudes (i.e., x=1/2) may be stable. This provides the semi-phenomenological theo

A. Kohen, G. Leibovitch, G. Deutscher

We have measured Andreev reflections between an Au tip and Y_{1-x}Ca_{x}Ba_{2}Cu_{3}O_{7 - δ} thin films in the in-plane orientation. The conductance spectra are best fitted with a pair potential having the &#34;d_{x^{2}-y^{2}+is&#34; symmetry. We find that the amplitude of the &#34;is&#34; component is enhanced as the contact transparency is increased. This

S. Parashar, A. R. Raju P. Victor, S. B. Krupanidhi, C. N. R. Rao

YMnO3 thin films have been grown on n - type Si substrates by nebulized spray pyrolysis in the Metal - Ferroelectric - Semiconductor (MFS) configuration. The C-V characteristics of the film in MFS structure exhibit hysteretic behavior consistent with the polarization charge switching direction, with the memory window decreasing with increase in temperature.

Manidipa Mitra, P. A. Sreeram, Sushanta Dattagupta

An exact treatment of the Anderson - Hasegawa two - site model, incorporating the presence of superexchange and polarons, is used to compute the heat capacity. The calculated results point to the dominance of the lattice contribution, especially in the ferromagnetic regime. This behavior is in qualitative agreement with experimental findings.

Giorgio Parisi

We show that the phonon-saddle transition in the ensemble of generalized inherent structures (minima and saddles) happens at the same point as the dynamical phase transition in glasses, that has been studied in the framework of the mode coupling approximation. The Boson peak observed in glasses at low temperature is a remanent of this transition.

G. Li, S. -J. Feng, F. Liu, Y. Yang

The magnetic transport properties have been measured for La0.67-xYxCa0.33MnO3 (0 <= x <= 0.14) system. It was found that the transition temperature Tp almost linearly moves to higher temperature as H increases. Electron spin resonance confirms that above Tp, there exist ferromagnetic clusters. From the magnetic polaron point of view, the shift of Tp vs. H wa

Giorgio Parisi

In this paper I will describe some results that have been recently obtained in the study of random Euclidean matrices, i.e. matrices that are functions of random points in Euclidean space. In the case of translation invariant matrices one generically finds a phase transition between a phonon phase and a saddle phase. If we apply these considerations to the s

P. -C. Ho, S. Moehlecke, M. B. Maple

The different pinning strengths of the flux line lattice in the peak effect (PE) region of a polycrystalline sample of CeRu$_2$ with a superconducting transition temperature {$T_c = 6.1$ K} have been probed by means of magnetization measurements with a SQUID magnetometer as the temperature $T$ and the magnetic field $H$ are varied. Magnetic relaxation measur

Kazumi Maki, Stephan Haas

The temperature and angular dependence of the c-axis Josephson current and the superfluid density in layered d-wave superconductors are studied within the framework of an extended Ambegaokar-Baratoff formalism. In particular, the effects of angle-dependent tunneling matrix elements and Andreev scattering at grain boundaries are taken into account. These lead

Petter Holme, Petter Minnhagen, Beom Jun Kim

The two-dimensional random gauge \xy model, where the quenched random variables are magnetic bond angles uniformly distributed within $[-rπ, rπ]$ ($0 \leq r \leq 1$), is studied via Monte Carlo simulations. We investigate the phase diagram in the plane of the temperature $T$ and the disorder strength $r$, and infer, in contrast to a prevailing conclusion in

T. Miyakawa, H. Christ, C. P. Search, P. Meystre

We analyze the full nonlinear dynamics of the four-wave mixing between an incident beam of fermions and a fermionic density grating. We find that when the number of atoms in the beam is comparable to the number of atoms forming the grating, the dephasing of that grating, which normally leads to a decay of its amplitude, is suppressed. Instead, the density gr

C. M. Martin, S. Guha, M. Chandrasekhar, H. R. Chandrasekhar

We present studies of the photoluminescence (PL), absorption and Raman scattering from poly[2,7-(9,9&#39;-bis(2-ethylhexyl))fluorene] under hydrostatic pressures of 0-100 kbar at room temperature. The well-defined PL and associated vibronics that are observed at atmospheric pressure change dramatically around 20 kbar in the bulk sample and at around 35 kbar

S. G. Djorgovski, S. R. Kulkarni, D. A. Frail, F. A. Harrison

Studies of the cosmic gamma-ray bursts (GRBs) and their host galaxies are now starting to provide interesting or even unique new insights in observational cosmology. Observed GRB host galaxies have a median magnitude R ~ 25 mag, and show a range of luminosities, morphologies, and star formation rates, with a median redshift z ~ 1. They represent a new way of

Kevin M. Huffenberger, Uros Seljak

We explore the connection between halo concentration and the dark matter power spectrum using the halo model. We fit halo model parameters to non-linear power spectra over a large range of cosmological models. We find that the non-linear evolution of the power spectrum generically prefers the concentration at non-linear mass scale to decrease with the effect