June 1999 arXiv papers — page 2

N. Fornengo, M. C. Gonzalez-Garcia, J. W. F. Valle

Flavour changing (FC) neutrino-matter interactions have been proposed as a solution to the atmospheric neutrino anomaly. Here we perform the analysis of the full set of the recent 52 kTy Super-Kamiokande atmospheric neutrino data, including the zenith angle distribution of the contained events as well as the higher energy upward-going stopping and through-go

Gert Aarts, Jan Smit

As a toy model for dynamics in nonequilibrium quantum field theory we consider the abelian Higgs model in 1+1 dimensions with fermions. In the approximate dynamical equations, inhomogeneous classical (mean) Bose fields are coupled to quantized fermion fields, which are treated with a mode function expansion. The effective equations of motion imply e.g. Coulo

V. Fock, A. Gorsky, N. Nekrasov, V. Rubtsov

We discuss various dualities, relating integrable systems and show that these dualities are explained in the framework of Hamiltonian and Poisson reductions. The dualities we study shed some light on the known integrable systems as well as allow to construct new ones, double elliptic among them. We also discuss applications to the (supersymmetric) gauge theo

Ralph Blumenhagen, Alok Kumar

We generalize the construction of four dimensional non-tachyonic orientifolds of type 0B string theory to non-supersymmetric backgrounds. We construct a four dimensional model containing self-dual D3 and D9-branes and leading to a chiral anomaly-free massless spectrum. Moreover, we discuss a further tachyon-free six dimensional model with only D5 branes. Eve

Donam Youm

We study the dynamics of the probe fundamental string in the field background of the partially localized supergravity solution for the fundamental string ending on Dp-brane. We separately analyze the probe dynamics for its motion along the worldvolume direction and the transverse direction of the source Dp-brane. We compare the dynamics of the probe along th

Dmitry Alekseevsky, Janusz Grabowksi, Giuseppe Marmo, Peter W. Michor

We present a slight generalization of the notion of completely integrable systems to get them being integrable by quadratures. We use this generalization to integrate dynamical systems on double Lie groups.

F. Delduc, L. Gallot, A. Sorin

A N=4 supersymmetric matrix KP hierarchy is proposed and a wide class of its reductions which are characterized by a finite number of fields are described. This class includes the one-dimensional reduction of the two-dimensional N=(2|2) superconformal Toda lattice hierarchy possessing the N=4 supersymmetry -- the N=4 Toda chain hierarchy -- which may be rele

D. R. Phillips, T. D. Cohen

The central tenet of effective theory is that the details of short-distance physics will not have a significant impact on low-energy observables. Here we perform an analysis of electron-deuteron scattering at low momentum transfers which is based on effective field theory. We show that in our approach the deuteron electromagnetic form factors $F_C$ and $F_M$

Mario Antonelli, Nicola Fabiano

We review the possibility of formation for a bound state made out of a stop quark and its antiparticle. The detection of a signal from its decay has been investigated for the case of a $e^+e^-$ collider.

N. F. Blagoveshchenskaya, V. A. Kornienko, T. D. Borisova, B. Thidé

Experimental results from Tromso HF pumping experiments in the nightside auroral E region are reported. We found intriguing evidence that a modification of the ionosphere-magnetosphere coupling, due to the effects of powerful HF waves beamed into an auroral sporadic E layer, can lead to a local intensification of the auroral activity. Summarizing multi-instr

Guido Cognola, Emilio Elizalde, Klaus Kirsten

A general calculation of Casimir energies --in an arbitrary number of dimensions-- for massless quantized fields in spherically symmetric cavities is carried out. All the most common situations, including scalar and spinor fields, the electromagnetic field, and various boundary conditions are treated with care. The final results are given as analytical (clos

Gilad Gour

Beginning with Bekenstein, many authors have considered a uniformly spaced discrete quantum spectrum for black hole horizon area. It is also believed that the huge degeneracy of these area levels corresponds to the notion of black hole entropy. Starting from these two assumptions we here infer the algebra of a Schwarzschild black hole's observables. This

Anthony Challinor

We present a 1+3 covariant discussion of the contribution of gravitational waves to the anisotropy of the CMB in an almost-Friedmann-Robertson-Walker universe. Our discussion is based in the covariant approach to perturbations in cosmology, which provides a physically transparent and gauge-invariant methodology for CMB physics. Applying this approach to line

P. Facchi, A. Mariano, S. Pascazio

We analyze the coherence properties of polarized neutrons, after they have interacted with a magnetic field or a phase shifter undergoing different kinds of statistical fluctuations. We endeavor to probe the degree of disorder of the distribution of the phase shifts by means of the loss of quantum mechanical coherence of the neutron. We find that the notion

Mary Beth Ruskai

In many physically realistic models of quantum computation, Pauli exchange interactions cause a subset of two-qubit errors to occur as a first order effect of couplings within the computer, even in the absence of interactions with the computer's environment. We give an explicit 9-qubit code that corrects both Pauli exchange errors and all one-qubit error

W. Y. Wang, Y. L. Wu, Y. A. Yan

The heavy quark effective field theory (HQEFT) containing both effective `quark fields' and `antiquark fields' is investigated in detail. By integrating out (but not neglecting) the effective antiquark fields, we present a new formulation of effective theory which differs from the usual heavy quark effective theory (HQET) and exhibits valuable featur

Robert Oeckl

We develop a general framework for quantum field theory on noncommutative spaces, i.e., spaces with quantum group symmetry. We use the path integral approach to obtain expressions for $n$-point functions. Perturbation theory leads us to generalised Feynman diagrams which are braided, i.e., they have non-trivial over- and under-crossings. We demonstrate the p

David H. Evans, Benjamin Grinstein, Detlef R. Nolte

Over a large fraction of phase space a combination of an operator product and heavy quark expansions effectively turn the decay $\bar B -> D^{(*)0} e+e-$ into a ``short distance'' process, i.e., one in which the weak and electromagnetic interactions occur through single local operators. These processes have an underlying W-exchange quark diagram topo

Naoki Itoh, Shugo Kusano, Tsuyoshi Sakamoto, Satoshi Nozawa

We present an accurate analytic fitting formula for the thermal bremsstrahlung Gaunt factor in the nonrelativistic limit. The fitting formula excellently reproduces the numerical results of the calculation carried out by the present authors using the method of Karzas and Latter. The present analytic fitting formula will be useful for the analysis of the X-ra

A. Hopkins, R. Windhorst, L. Cram, R. Ekers

An international project is underway to design and build a radio telescope with an effective collecting area two orders of magnitude greater than the largest existing instruments. One of the many scientific goals of this instrument will be the investigation of the extragalactic radio source population at flux densities two to three orders of magnitude fainte

B. T. Soifer, K. Matthews, G. Neugebauer, L. Armus

Near infrared imaging and spectroscopic observations of the extremely red object (R-K~ 7 mag) CL 0939+4713 B have been obtained with the Near Infrared Camera on the Keck I Telescope of the W. M. Keck Observatory. The imaging shows a slightly elongated structure, while the spectroscopy shows a continuum break that allows us to determine the redshift of z = 1.

N. Bahcall, J. P. Ostriker, S. Perlmutter, P. J. Steinhardt

The "cosmic triangle" is introduced as a way of representing the past, present, and future status of the universe. Our current location within the cosmic triangle is determined by the answers to three questions: How much matter is in the universe? Is the expansion rate slowing down or speeding up? And, is the universe flat? A review of recent observations su

Lucien Hardy

Quantum entanglement can be used to demonstrate nonlocality and to teleport a quantum state from one place to another. The fact that entanglement can be used to do both these things has led people to believe that teleportation is a nonlocal effect. In this paper it is shown that teleportation is conceptually independent of nonlocality. This is done by constr

G. Plunien, R. Schützhold, G. Soff

Thermal effects on the creation of particles under the influence of time-dependent boundary conditions are investigated. The dominant temperature correction to the energy radiated by a moving mirror is derived by means of response theory. For a resonantly vibrating cavity the thermal effect on the number of created photons is obtained non-perturbatively. Fin

L. N. Labzowsky, A. V. Nefiodov, G. Plunien, G. Soff

The hyperfine structure (hfs) of electron levels of $^{238}_{92}$U ions with the nucleus excited in the low-lying rotational $2^+$ state with an energy $E_{2^+} = 44.91$ keV is investigated. In hydrogenlike uranium, the hfs splitting for the $1s_{1/2}$-ground state of the electron constitutes 1.8 eV. The hyperfine-quenched (hfq) lifetime of the $1s2p ^3P_0$

Julian Juhi-Lian Ting

The possibility of stochastic resonance of a quantum channel and hence the noise enhanced quantum channel capacity is explored by considering one-Pauli channels which are more classical like. The fidelity of the channel is also considered.

H. P. Breuer, D. Faller, B. Kappler, F. Petruccione

The dynamics of atom lasers with a continuous output coupler based on two-photon Raman transitions is investigated. With the help of the time-convolutionless projection operator technique the quantum master equations for pulsed and continuous wave (cw) atom lasers are derived. In the case of the pulsed atom laser the power of the time-convolutionless project

George Svetlichny

We investigate the symmetry properties of hierarchies of non-linear Schroedinger equations (introduced by Doebner and Goldin, and Goldin and Svetlichny), which describe non-interacting systems in which tensor product wave-functions evolve by independent evolution of the factors (the separation property). We show that there are obstructions to lifting symmetr

Xinlan Zhou, Debbie W. Leung, Isaac L. Chuang

Realistic physical implementations of quantum computers can entail tradeoffs which depart from the ideal model of quantum computation. Although these tradeoffs have allowed successful demonstration of certain quantum algorithms, a crucial question is whether they fundamentally limit the computational capacity of such machines. We study the limitations of a q

Gregg Jaeger

A review of "Bohmian Mechanics and Quantum Theory: An Appraisal" (James Cushing, Arthur Fine and Sheldon Goldstein, Eds.), an extensive collection of articles on Bohmian mechanics. In addition to broad, critical overviews of Bohmian mechanics, the reviewed collection contains extensions and hybrid versions of the theory and several detailed applicati

H. D. Zeh

The conceptual and dynamical aspects of decoherence are analyzed, while their consequences are discussed for several fundamental applications. This mechanism, which is based on a universal Schrödinger equation, is furthermore compared with the phenomenological description of open systems in terms of `quantum dynamical maps'.

G. Quznetsov

The sufficient and necessary conditions for a nonzero fermion mass without Higgs are considered. The Parity Violation is deduced from these conditions.

S. Jadach

I show how to construct Monte Carlo algorithms (programs), prove that they are correct and document them. Complicated algorithms are build using a handful of elementary methods. This construction process is transparently illustrated using graphical representation in which complicated graphs consist of only several elementary building blocks. In particular I

R. Bijker, A. Leviatan

We discuss recent calculations of the mass spectrum, electromagnetic and strong couplings of baryon resonances. The calculations are done in a collective constituent model for the nucleon, in which the resonances are interpreted as rotations and vibrations of a symmetric top with a prescribed distribution of the charge and magnetization. We analyze recent da

G. Roepke, A. Schnell, P. Schuck, U. Lombardo

Isospin singlet (pn) pairing as well as quartetting in nuclei is expected to arise near the symmetry line $N=Z$. Empirical values can be deduced from the nuclear binding energies applying special filters. Within the local density approximation, theoretical estimates for finite nuclei are obtained from results for the condensation energy of asymmetric nuclear

O. Krehl, C. Hanhart, S. Krewald, J. Speth

We present an alternative method for calculating amplitudes for correlated pi pi exchange in the ``sigma'' and rho channel in piN scattering. Starting from a fixed mass meson exchange potential, we introduce the width of the exchanged particles by integrating over a mass spectral function. The spectral functions are constructed from the pseudoempiric

Arnd Bäcker, Grischa Haag

We study the spectral statistics for quantized skew translations on the torus, which are ergodic but not mixing for irrational parameters. It is shown explicitly that in this case the level--spacing distribution and other common spectral statistics, like the number variance, do not exist in the semiclassical limit.

Banibrata Mukhopadhyay, Subhadip Raychaudhuri

For the cases of irreducible representation, the complete set of operators necessary to specify uniquely the states. There are two ways of representing the state, using uncoupled and coupled basis. Here we discuss, how the number of operators for the cases of coupled and uncoupled basis changes as well as their difference with the increase of dimension. For

T. Gannon

Unimodal (i.e. single-humped) permutations may be decomposed into a product of disjoint cycles. Some enumerative results concerning their cyclic structure -- e.g. 2/3 of them contain fixed points -- are given. We also obtain in effect a kind of combinatorial universality for continuous unimodal maps, by severely constraining the possible ways periodic orbits

Andrew Hassell, Andras Vasy

In this paper we consider certain asymptotically Euclidean spaces, namely compact manifolds with boundary X equipped with a scattering metric g, as defined by Melrose. We then consider Hamiltonians H which are `short-range' self-adjoint perturbations of the Laplacian of g. Melrose and Zworski have given a detailed description of the associated scattering

Ralf Meyer

We prove excision in entire and periodic cyclic cohomology and construct a Chern-Connes character for Fredholm modules over a C*-algebra without summability restrictions, taking values in a variant of Connes's entire cyclic cohomology. Before these results can be obtained, we have to sort out some fundamental questions about the class of algebras on whic

Steven P. Diaz, Anthony V. Geramita, Juan C. Migliore

Given a finite set, $X$, of points in projective space for which the Hilbert function is known, a standard result says that there exists a subset of this finite set whose Hilbert function is ``as big as possible'' inside $X$. Given a finite set of points in projective space for which the minimal free resolution of its homogeneous ideal is known, what

Boris Shapiro, Michael Shapiro, Alek Vainshtein, Andrei Zelevinsky

Let W be an arbitrary Coxeter group of simply-laced type (possibly infinite but of finite rank), u,v be any two elements in W, and i be a reduced word (of length m) for the pair (u,v) in the Coxeter group W\times W. We associate to i a subgroup Gamma_i in GL_m(Z) generated by symplectic transvections. We prove among other things that the subgroups correspond

Jacob v. B. Hjelmborg

Pure infiniteness (in sense of E.Kirchberg and M.Rørdam) is considered for C*-algebras arising from singly generated dynamical systems. In particular, Cuntz-Krieger algebras and their generalizations, i.e., graph-algebras and O_A of an infinite matrix A, admit characterizations of pure infiniteness. As a consequence, these generalized Cuntz-Krieger algebras

Masaki Kashiwara, Pierre Schapira

This is an announcement of a long paper in progress. On a locally compact space, we introduce the stack of ind-sheaves (ind-objects of the category of sheaves with compact support) and construct the analogous of the usual six operations on sheaves. As an application, we treat, in the formalism of ind-sheaves, functions with growth conditions such as the ``te

Boju Jiang, Xiao-Song Lin, Shicheng Wang, Ying-Qing Wu

We will develop various methods, some are of geometric nature and some are of algebraic nature, to detect the various achiralities of knots and links in $S^3$. For example, we show that the twisted Whitehead double of a knot is achiral if and only if the double is the unknot or the figure eight knot, and we show that all non-trivial links with $\leq9$ crossi

Louis Funar, Tom L. Thickstun

We prove that an open 3-manifold proper homotopy equivalent to a geometrically simply connected polyhedron is simply connected at infinity, generalizing a theorem of V.Poenaru.

H. W. Braden, A. Marshakov, A. Mironov, A. Morozov

We construct a two parameter family of 2-particle Hamiltonians closed under the duality operation of interchanging the (relative) momentum and coordinate. Both coordinate and momentum dependence are elliptic, and the modulus of the momentum torus is a non-trivial function of the coordinate. This model contains as limiting cases the standard Ruijsenaars-Calog

David Kastor, Jennie Traschen

We compare oscillations of a fundamental string ending on a D3-brane in two different settings: (1) a test-string radially threading the horizon of an extremal black D3-brane and (2) the spike soliton of the DBI effective action for a D3-brane. Previous work has shown that overall transverse modes of the test-string appear as l=0 modes of the transverse scal

A. Gomez Nicola, R. J. Rivers, D. A. Steer

We show that in certain limits the (1+1)-dimensional massive Thirring model at finite temperature $T$ is equivalent to a one-dimensional Coulomb gas of charged particles at the same $T$. This equivalence is then used to explore the phase structure of the massive Thirring model. For strong coupling and $T>>m$ (the fermion mass) the system is shown to behave a

J. C. Brunelli, M. Gurses, K. Zheltukhin

We give the Lax representations for for the elliptic, hyperbolic and homogeneous second order Monge-Ampere equations. The connection between these equations and the equations of hydrodynamical type give us a scalar dispersionless Lax representation. A matrix dispersive Lax representation follows from the correspondence between sigma models, a two parameter e

Sergiu Ostaf

The article gives explicit calculation and interpretation of the additional locally anisotropic effects. Double role of the resulted gauge like fields discussed.

Thomas Strobl

The N=1 supersymmetric version of generalized 2d dilaton gravity can be cast into the form of a Poisson Sigma Model, where the target space and its Poisson bracket are graded. The target space consists of a 1+1 superspace and the dilaton, which is the generator of Lorentz boosts therein. The Poisson bracket on the target space induces the invariance of the w

E. Elizalde

The concept of determinant for a linear operator in an infinite-dimensional space is addressed, by using the derivative of the operator's zeta-function (following Ray and Singer) and, eventually, through its zeta-function trace. A little play with operators as simple as $\pm I$ ($I$ being the identity operator) and variations thereof, shows that the pres

D. Chruscinski

We find a universal SO(2) symmetry of a p-form Maxwell theory for both odd and even p. For odd p it corresponds to the duality rotations but for even p it defines a new set of transformations which is not related to duality rotations. In both cases a symmetry group defines a subgroup of the O(2,1) group of R-linear canonical transformations which has also a

Vijay Balasubramanian, Simon F. Ross

In anti-de Sitter (AdS) space, classical supergravity solutions are represented "holographically" by conformal field theory (CFT) states in which operators have expectation values. These 1-point functions are directly related to the asymptotic behaviour of bulk fields. In some cases, distinct supergravity solutions have identical asymptotic behaviour

Tancredi Carli

Different choices of the renormalisation scale (muren) can be used to describe hard scattering processes with two jets at large transverse momentum in deep-inelastic scattering at HERA by fixed order perturbative QCD calculations. For leading (LO) and next-to-leading order (NLO) calculations the simplest choices, Q2, the virtuality of the incoming photon, an

Tancredi Carli

Recent data obtained in ep collisions at HERA by the H1 collaboration are presented: searches for new phenomena beyond the Standard Model, measurement of the inclusive neutral and charged current cross sections and of the proton structure function, determination of the gluon density in the proton and photon from jet productions, measurement and interpretatio

Michael A. Doncheski

In this report, I will present the current status of the low-mass axigluon. The axigluon is a massive, color octet, axial vector boson, predicted in, e.g., chiral color models and some technicolor models, with a mass of order the electroweak scale. Axigluons with a mass larger than about 125 GeV to nearly 1 TeV can be eliminated by di-jet production at hadro

Bronislav G. Zakharov

We develop a formalism for evaluation of the transverse momentum dependence of cross sections of the radiation processes in medium. The analysis is based on the light-cone path integral approach to the induced radiation. The results are applicable in both QED and QCD.

I. B. Khriplovich

Upper limits on the electric dipole moments (EDM) of elementary particles and atoms are presented, and their physical implications are discussed. The bounds following from the neutron and atomic experiments are comparable. In particular, they strongly constrain P odd, T even interactions. The nuclear EDMs can be studied at ion storage rings, with the expecte

A. Schäfer

A number of physics arguments for a high-luminosity high energy polarized Electron- Nucleon/Nucleus-Collider (i.e. with a luminosity of at least 10^{33} cm^{-2} sec^{-1} and an invariant energy squarred of at least s >= 100 GeV^2) are presented. The main purpose of this machine would be generally speaking the investigation of QCD beyond the twist-2 level res

K. Hencken, P. Stagnoli, D. Trautmann, G. Baur

Due to the coherence of all the protons in a nucleus, there are very strong electromagnetic fields of short duration in relativistic heavy ion collisions. They give rise to quasireal photon-photon and photon-nucleus collisions with a large flux. RHIC will begin its experimental program this year and such types of collisions will be studied experimentally at

Hisakazu Minakata, Shinji Watanabe

We examine the possibility of detecting effects of leptonic CP violation by precise measurement of the solar neutrinos within the framework of standard electroweak theory minimally extended to include neutrino masses and mixing. We prove a ``no-go theorem'' which states that effects of CP violating phase disappear in the nu_e survival probability to

Takeo Moroi, Lisa Randall

The cosmological moduli problem is discussed in the framework of sequestered sector/anomaly-mediated supersymmetry (SUSY) breaking. In this scheme, the gravitino mass (corresponding to the moduli masses) is naturally 10 - 100 TeV, and hence the lifetime of the moduli fields can be shorter than $\sim 1 sec$. As a result, the cosmological moduli fields should

Jiri Chyla, Marek Tasevsky

Interactions of virtual photons are analyzed in terms of photon structure. It is argued that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. The role of longitudinal photons for proper interpretation of jet cross--sections in the region of moderate virtualities access

Wolfram Kittel

Color reconnection and Bose-Einstein correlations not only can have an influence on the measurement of the W-mass in the fully hadronic W+W- decay channel at LEP2, but also can give essential information on the structure of the QCD vacuum and the space-time development of a q_1\bar q_2 system. Recent developments are critically analyzed, with particular emph

U. K. Yang et al

We report on a measurement of the neutrino-nucleon and antineutrino-nucleon differential cross sections in the CCFR detector. The measurement of the differential cross sections over a wide range of energies allows Delta xF_3 = xF_3(nu)-xF_3(anti-nu) and R to be extracted. Delta xF_3 is related to the difference between the contributions of the strange and ch

The OPAL Collaboration, G. Abbiendi et al

A measurement of inclusive semileptonic branching fractions of b hadrons produced in Z decays is presented. An enriched Z -> bbbar sample is obtained with a lifetime flavour-tagging technique. The leptonic events are then selected from this sample, and classified according to their origin, which is determined by comparing the distribution of several kinemati

Valery Koryukin

The detection and the research of the neutrinos background of Universe are the attractive problems. This problems do not seem the unpromising one in the case of the high neutrinos density that is necessary for the explanation of the nucleons-antinucleons asymmetry of Universe. It was offered before to use the low energy neutrinos background of Universe for t

J. W. van Holten

We examine the motion of a relativistic charged particle in a constant magnetic field perturbed by gravitational waves incident along the direction of the magnetic field. We apply a generalized energy conservation law to compute the variations of the kinetic energy of the particle during passage of the waves. We also explicitly compute the change in the orbi

Farhad Darabi

We study a model of quantum cosmology originating from a classical model of gravitation where a self interacting scalar field is coupled to gravity with the metric undergoing a signature transition. We show that there are dual classical signature changing solutions, one at large scales and the other at small scales. It is possible to fine-tune the physics in

L. Fatibene, M. Ferraris, M. Francaviglia, M. Raiteri

A geometrical framework for the definition of entropy in General Relativity via Noether theorem is briefly recalled and the entropy of Taub-Bolt Euclidean solutions of Einstein equations is then obtained as an application. The computed entropy agrees with previously known results, obtained by statistical methods. It was generally believed that the entropy of

John D. Anderson, Philip A. Laing, Eunice L. Lau, Anthony S. Liu

We conclude that Murphy's proposal (radiation of the power of the main-bus electrical systems from the rear of the craft) can not explain the anomalous Pioneer acceleration.

John D. Anderson, Philip A. Laing, Eunice L. Lau, Anthony S. Liu

We conclude that Katz's proposal (anisotropic heat reflection off of the back of the spacecraft high-gain antennae, the heat coming from the RTGs) does not provide enough power and so can not explain the Pioneer anomaly.

Jin-Yi Cai, Lane A. Hemaspaandra, Gerd Wechsung

We continue the study of robust reductions initiated by Gavalda and Balcazar. In particular, a 1991 paper of Gavalda and Balcazar claimed an optimal separation between the power of robust and nondeterministic strong reductions. Unfortunately, their proof is invalid. We re-establish their theorem. Generalizing robust reductions, we note that robustly strong r

A. Wong, M. Chechik

This paper describes a case study conducted in collaboration with Nortel to demonstrate the feasibility of applying formal modeling techniques to telecommunication systems. A formal description language, SDL, was chosen by our qualitative CASE tool evaluation to model a multimedia-messaging system described by an 80-page natural language specification. Our m

M. Chechik, D. Paun

A pattern-based approach to the presentation, codification and reuse of property specifications for finite-state verification was proposed by Dwyer and his collegues. The patterns enable non-experts to read and write formal specifications for realistic systems and facilitate easy conversion of specifications between formalisms, such as LTL, CTL, QRE. In this

Alexander N. Korotkov

We consider the continuous quantum measurement of a two-level system, for example, a single-Cooper-pair box measured by a single-electron transistor or a double-quantum dot measured by a quantum point contact. While the approach most commonly used describes the gradual decoherence of the system due to the measurement, we show that when taking into account th

R. J. Radwanski, Z. Ropka

It has been shown that the crystal-field interactions can produce a non- magnetic singlet ground state for the highly-correlated d6 system situated in the quasi-octahedral crystal field (CEF) surrounding provided the spin-orbit interactions are correctly taking into account. The spin-orbit interactions in combination with the trigonal distortion of the cubic

X. Guardiola, A. Diaz-Guilera

We study spatio-temporal pattern formation in a ring of N oscillators with inhibitory unidirectional pulselike interactions. The attractors of the dynamics are limit cycles where each oscillator fires once and only once. Since some of these limit cycles lead to the same pattern, we introduce the concept of pattern degeneracy to take it into account. Moreover

Bertrand Roehner, D. Sornette

We document and analyze the empirical facts concerning one of the clearest evidence of speculation in financial trading as observed in the postage collection stamp market. We unravel some of the mechanisms of speculative behavior which emphasize the role of fancy and collective behavior. In our conclusion, we propose a classification of speculative markets b

Dietrich Stauffer, D. Sornette

In the Cont-Bouchaud model [cond-mat/9712318] of stock markets, percolation clusters act as buying or selling investors and their statistics controls that of the price variations. Rather than fixing the concentration controlling each cluster connectivity artificially at or close to the critical value, we propose that clusters shatter and aggregate continuous

A. A. Likhachev, K. Ullakko

A quantitative model describing large magnetostrain effect observed in several ferromagnetic shape memory alloys such as Ni2MnGa is briefly reported.The paper contains an exact thermodynamic consideration of the mechanical and magnetic properties for a similar type materials. As a result, the basic mechanical state equation including magnetic field effect is

J. Röhler

Oxygen doping dimples the CuO_2 planes of YBa_2Cu_3O_{6.8-6.92} by displacing copper normal to the planes and further towards Ba. The correlated oxygen displacements, however, are constrained to the in-plane axes. This displacement pattern is discussed in terms of doping dependent Cu 4s - 3d hybridizations.

Tooru Taniguchi, Markus Buttiker

We illustrate the relation between the scattering phase appearing in the Friedel sum rule and the phase of the transmission amplitude for quantum scatterers connected to two one-dimensional leads. Transmission zero points cause abrupt phase changes $\pmπ$ of the phase of the transmission amplitude. In contrast the Friedel phase is a continuous function of en

Vladimir Shvetsov, Dirk Helbing

We present a macroscopic model of mixed multi-lane freeway traffic that can be easily calibrated to empirical traffic data, as is shown for Dutch highway data. The model is derived from a gas-kinetic level of description, including effects of vehicular space requirements and velocity correlations between successive vehicles. We also give a derivation of the

Paul R. Van Tassel, Pascal Viot, Gilles Tarjus, Jeremy J. Ramsden

Many experimental studies of protein deposition on solid surfaces involve alternating adsorption/desorption steps. In this paper, we investigate the effect of a desorption step (separating two adsorption steps) on the kinetics, the adsorbed-layer structure, and the saturation density. Our theoretical approach involves a density expansion of the pair distribu

J. Talbot, G. Tarjus, P. R. Van Tassel, P. Viot

The adsorption or adhesion of large particles (proteins, colloids, cells, >...) at the liquid-solid interface plays an important role in many diverse applications. Despite the apparent complexity of the process, two features are particularly important: 1) the adsorption is often irreversible on experimental time scales and 2) the adsorption rate is limited b

Raffaele Cafiero, Angelo Valleriani, Josè Luis Vega

We study the behavior under perturbations of different versions of Bak-Sneppen (BS) model in 1 + 1 dimension. We focus our attention on the damage-spreading features of the BS model with both random as well as deterministic updating, with sequential as well as parallel updating. In addition, we compute analytically the asymptotic plateau reached by the dista

Masamichi Nishino, Hiroaki Onishi, Pascal Roos, Kizashi Yamaguchi

We study the magnetic properties of $S=1/2$ antiferromagnetic Heisenberg chains with inhomogeneity of interaction. Using a quantum Monte Carlo method and an exact diagonalization method, we study bond-impurity effect in the uniform $S=1/2$ chain and also in the bond-alternating chain. Here `bond impurity' means a bond with strength different from those i

Tohru Okamoto, K. Hosoya, S. Kawaji, A. Yagi

Magnetotransport in 2DES's formed in Si-MOSFET's and Si/SiGe quantum wells at low temperatures is reported. Metallic temperature dependence of resistivity is observed for the n-Si/SiGe sample even in a parallel magnetic field of 9T, where the spins of electrons are expected to be polarized completely. Correlation between the spin polarization and min

L. Henrard, E. Hernandez, P. Bernier, A. Rubio

We have developed a pair-potential approach for the evaluation of van der Waals interaction between carbon nanotubes in bundles. Starting from a continuum model, we show that the intertube modes range from $5 cm^{-1}$ to $60 cm^{-1}$. Using a non-orthogonal tight-binding approximation for describing the covalent intra-tube bonding in addition, we confirme a

Owen G. Jepps, Gary Ayton, Denis J. Evans

We show that arbitrary phase space vector fields can be used to generate phase functions whose ensemble averages give the thermodynamic temperature. We describe conditions for the validity of these functions in periodic boundary systems and the Molecular Dynamics (MD) ensemble, and test them with a short-ranged potential MD simulation.

H. Matsumoto, S. Sakamoto, F. Wajima, T. Koyama

I-V characteristics of the high T$_c$ superconductor Bi$_2$Sr$_2$Ca$_1$C$_2$O$_8$ shows a strong hysteresis, producing many branches. The origin of hysteresis jumps is studied by use of the model of multi-layered Josephson junctions proposed by one of the authors (T. K.). The charging effect at superconducting layers produces a coupling between the next near

R. Moessner, A. J. Berlinsky

We investigate the magnetic susceptibility of the classical Heisenberg antiferromagnet with nearest-neighbour interactions on the geometrically frustrated pyrochlore lattice, for a pure system and in the presence of dilution with nonmagnetic ions. Using the fact that the correlation length in this system for small dilution is always short, we obtain an appro

A. Yu. Cherny, A. A. Shanenko

The well-known results concerning a dilute Bose gas with the short-range repulsive interaction should be reconsidered due to a thermodynamic inconsistency of the method being basic to much of the present understanding of this subject and nonrelevant behaviour of the pair distribution function at small boson separations. The aim of our paper is to propose a n

Yuri V. Lvov, Ildar R. Gabitov

We show that an integro-differential equation model for pulse propagation in optical transmission lines with dispersion management, is integrable at the {\it leading nonlinear order}. This equation can be transformed into the nonlinear Schroedinger equation by a near-identity canonical transformation for the case of weak dispersion. We also derive the next o

Harel Primack, Uzy Smilansky

We present a comprehensive semiclassical investigation of the three-dimensional Sinai billiard, addressing a few outstanding problems in "quantum chaos". We were mainly concerned with the accuracy of the semiclassical trace formula in two and higher dimensions and its ability to explain the universal spectral statistics observed in quantized chaotic

L. Baroni, R. Livi, A. Torcini

Synchronization is shown to occur in spatially extended systems under the effect of additive spatio-temporal noise. In analogy to low dimensional systems, synchronized states are observable only if the maximum Lyapunov exponent $Λ$ is negative. However, a sufficiently high noise level can lead, in map with finite domain of definition, to nonlinear propagatio