July 2002 arXiv papers — page 7

David P. DiVincenzo, Patrick Hayden, Barbara M. Terhal

Recent work has shown how to use the laws of quantum mechanics to keep classical and quantum bits secret in a number of different circumstances. Among the examples are private quantum channels, quantum secret sharing and quantum data hiding. In this paper we show that a method for keeping two classical bits hidden in any such scenario can be used to construc

K. Audenaert, M. B. Plenio, J. Eisert

We study the entanglement cost under quantum operations preserving the positivity of the partial transpose (PPT-operations). We demonstrate that this cost is directly related to the logarithmic negativity, thereby providing the operational interpretation for this easily computable entanglement measure. As examples we discuss general Werner states and arbitra

O. Nicrosini, A. Rimini

A new proposal for a Lorentz-invariant spontaneous localization theory is presented. It is based on the choice of a suitable set of macroscopic quantities to be stochastically induced to have definite values. Such macroscopic quantities have the meaning of a time-integrated amount of a microscopically defined quantity called stuff related to the presence of

A. K. Pati, S. R. Jain, A. Mitra, R. Ramanna

We investigate if physical laws can impose limit on computational time and speed of a quantum computer built from elementary particles. We show that the product of the speed and the running time of a quantum computer is limited by the type of fundamental interactions present inside the system. This will help us to decide as to what type of interaction should

Jyrki Piilo

We present a simple method to calculate the binary collision rate between atoms in near-resonant optical lattices. The method is based on the Monte Carlo wave function simulations and the collision rate is obtained by monitoring the quantum flux beyond the average distance between the atoms. To illustrate the usefulness of the method, we calculate the collis

Sanghyun Park, Melih K. Sener, Deyu Lu, Klaus Schulten

Photosystem I is a protein-pigment complex that performs photosynthesis in plants, green algae, and cyanobacteria. It contains an aggregate of chlorophylls that absorbs light and delivers the resulting electronic excitation to the special pair of chlorophylls where the excitation energy is used for producing charge separation across the cell membrane. The se

V. A. Gani, A. E. Kudryavtsev, V. A. Lensky, V. M. Weinberg

The states of hydrogen atom with principal quantum number n <= 3 and zero magnetic quantum number in constant homogeneous magnetic field H are considered. The perturbation theory series is summed with the help of Borel transformation and conformal mapping of the Borel variable. Convergence of approximate energy eigenvalues and their agreement with correspond

R. Ball, A. C. McIntosh, J. Brindley

A simple dynamical system that models the competitive thermokinetics and chemistry of cellulose decomposition is examined, with reference to evidence from experimental studies indicating that char formation is a low activation energy exothermal process and volatilization is a high activation energy endothermal process. The thermohydrolysis chemistry at the c

J. Dobaczewski, J. Dudek, R. Wyss

The superdeformed bands in 58Cu, 59Cu, 60Zn, and 61Zn are analyzed within the frameworks of the Skyrme-Hartree-Fock as well as Strutinsky-Woods-Saxon total routhian surface methods with and without the T=1 pairing correlations. It is shown that a consistent description within these standard approaches cannot be achieved. A T=0 neutron-proton pairing configur

V. A. Karmanov, J. Carbonell

The light-front dynamics is an efficient approach to study of field theory and of relativistic composite systems (nuclei at relativistic relative nucleon momenta, hadrons in the quark models). The explicitly covariant version of this approach is briefly reviewed and illustrated by some applications.

J. Carbonell, V. A. Karmanov

For the zero-range interaction providing a given mass M_2 of the two-body bound state, the mass M_3 of the relativistic three-boson state is calculated. We have found that the three-body system exists only when M_2 is greater than a critical value M_c approximately 1.43 m (m is the constituent mass). For M_2=M_c the mass M_3 turns into zero and for M_2<M_c t

H. Krebs, V. Bernard, Ulf-G. Meißner

Near threshold neutral pion electroproduction on the deuteron is studied in the framework of baryon chiral perturbation theory at next-to-leading order in the chiral expansion. We develop the multipole decomposition for pion production off spin-1 particles appropriate for the threshold region. The existing data at photon virtuality k^2 = -0.1 GeV^2 can be de

Yun Zhang, Ru-Keng Su

Using the quark mass density- and temperature dependent model, we have studied the thermodynamical properties and the stability of strangelet at finite temperature. The temperature, charge and strangeness dependences on the stability of strangelet are investigated. We find that the stable strangelets are only occured in the high strangeness and high negative

D. Kudzia, B. Wilczynska, H. Wilczynski

An attempt to extract critical exponents gamma, beta and tau from data on gold nuclei fragmentation due to interactions with nuclear emulsion at energies 4.0 A GeV and 10.6 A GeV is presented. Based on analysis of Campi&#39;s 2nd charge moments, two subsets of data at each energy are selected from the inclusive data, corresponding to &#39;liquid&#39; and &#3

Tsampikos Kottos, Uzy Smilansky

We connect quantum graphs with infinite leads, and turn them to scattering systems. We show that they display all the features which characterize quantum scattering systems with an underlying classical chaotic dynamics: typical poles, delay time and conductance distributions, Ericson fluctuations, and when considered statistically, the ensemble of scattering

Henryk Fuks, Anna T. Lawniczak

We present a lattice gas cellular automaton (LGCA) to study spatial and temporal dynamics of an epidemic of SIR (susceptible-infected-removed) type. The automaton is fully discrete, i.e. space, time and number of individuals are discrete variables. The automaton can be applied to study spread of epidemics in both human and animal populations. We investigate

Henryk Fuks

We demonstrate that a local mapping f in a space of bisequences over {0,1} which conserves the number of nonzero sites can be viewed as a deterministic particle system evolving according to a local mapping in a space of increasing bisequences over Z. We present an algorithm for determination of the local mapping in the space of particle coordinates correspon

T. A. Kozhamkulov, Kuralay Myrzakul, R. Myrzakulov

We conjecture that many (maybe all) integrable equations and spin systems in 2+1 dimensions can be obtained from the (2+1)-dimensional Gauss-Mainardi-Codazzi and Gauss-Weingarten equations, respectively. We also show that the (2+1)-dimensional Gauss-Mainardi-Codazzi equation which describes the deformation (motion) of surfaces is the exact reduction of the Y

I. Catto, Ch. Hainzl

We investigate the self-energy of one electron coupled to a quantized radiation field by extending the ideas developed recently by C. Hainzl. We fix an arbitrary cut-off parameter Lambda and recover the alpha^2-term of the self-energy, where alpha is the coupling parameter representing the fine structure constant. Thereby we develop a method which allows to

Anastasios Mallios

Applying the classical Serre-Swan theorem, as this is extended to topological (non-normed) algebras, one attains a classification of elementary particles via their spin-structure. In this context, our argument is virtually based on a ``correspondence principle&#39;&#39; of S. A. Selesnick, formulated herewith in a sheaf-theoretic language, presisely speaking

Maurice de Gosson

Symplectic topology has become a thriving area of research in mathematics and physics since Gromov&#39;s discovery in 1985 of a surprising property of canonical transformations (and hence of hamiltonian flows),&#34;the principle of the symplectic camel&#34;. We exploit this property to show that the usually EBK quantization is equivalent to the physical assu

M. Farinati, A. Solotar

We prove that Ext^*_A(k,k) is a Gerstenhaber algebra, where A is a Hopf algebra. In case A=D(H) is the Drinfeld double of a finite dimensional Hopf algebra H, our results implies the existence of a Gerstenhaber bracket on H^*_{GS}(H,H). This fact was conjectured by R. Taillefer in math.KT0207154. The method consists in identifying Ext^*_A(k,k) as a Gerstenha

Meirav Amram, Mina Teicher

In this article, we compute the braid monodromy of two algebraic curves defined over R. These two curves are of complex level not bigger than 6, and they are unions of lines and conics. We use two different techniques for computing their braid monodromies. These results will be applied to computations of fundamental groups of their complements in C^2 and C P

S. Walters

For any irrational theta and rational number p/q such that q|qtheta-p|<1, a projection e of trace q|qtheta-p| is constructed in the the irrational rotation algebra A_theta that is invariant under the Fourier transform. (The latter is the order four automorphism U mapped to V, V mapped to U^{-1}, where U, V are the canonical unitaries generating A_theta.) Fur

Sergei Chmutov

A few years ago N.A&#39;Campo invented a construction of a link from a real curve immersed into a disk. In the case of the curve originating from the real morsification method the link is isotopic to the link of the corresponding singularity. There are some curves which do not occur in the singularity theory. In this article we describe the Casson invariant

Luis Baez-Duarte

A formal description of a functional analysis approach to the Riemann zeta-functional equation that provides in principle an infinity of different proofs based on work by the author on the existence of dilation-invariant unitary operators in L2 of the positive real line.

B. Enriquez, F. Gavarini, G. Halbout

Any quantization of a quasitriangular Lie bialgebra g gives rise to a braiding of the dual Poisson-Lie formal group G^*. We show that this braiding always coincides with the Weinstein-Xu braiding. We also define the lifts of the classical r-matrix r as certain functions on G^* x G^*, prove their existence and uniqueness using co-Hochschild cohomology argumen

Roberto De Leo

Novikov&#39;s problem of semiclassical orbits of quasi-electrons in a normal metal leads to a correspondance between 3-ply periodic functions in R and fractals in R P^2. These fractals are the complement of infinitely many open sets labeled by integer 2-cycles of T^3. Here we present a characterization of the fractal points in terms of the open sets labels.

Andrei Okounkov, Rahul Pandharipande

We express all equivariant Gromov-Witten invariants of the projective line as matrix elements of explicit operators acting in the Fock space. As a consequence, we prove the equivariant theory is governed by the 2-Toda hierarchy of Ueno and Takasaki. This is the second in a sequence of three papers devoted to the Gromov-Witten theory of nonsingular target cur

Gianni Dal Maso, Helene Frankowska

This paper is devoted to the autonomous Lagrange problem of the calculus of variations with a discontinuous Lagrangian. We prove that every minimizer is Lipschitz continuous if the Lagrangian is coercive and locally bounded. The main difference with respect to the previous works in the literature is that we do not assume that the Lagrangian is convex in the

Walter Bergweiler, A. Eremenko, J. K. Langley

If f is a real entire function and ff&#34; has only real zeros then f belongs to the Laguerre-Polya class, the closure of the set of real polynomials with real zeros. This result completes a long line of development originating from a conjecture of Wiman in 1914.

Gregory Freiman, Boris Granovsky

We construct a probability model seemingly unrelated to the considered stochastic process of coagulation and fragmentation. By proving for this model the local limit theorem, we establish the asymptotic formula for the partition function of the equilibrium measure for a wide class of parameter functions of the process. This formula proves the conjecture stat

G. Mockenhaupt, W. Schlag

The Hardy-Littlewood majorant problem asks whether L^p norms of functions on the circle grow if one replaces their Fourier coefficients with their absolute values. This is clear if p is an even integer, but false if p is any other number. One can still ask if the norm grows at most by the degree raised to a small power for any p. We show that this is so with

Adam Sikora, Terence Tao

We prove that spectral projections of Laplace-Beltrami operator on the m-complex unit sphere E_{Delta_{S^{2m-1}}}([0,R)) are uniformly bounded as an operator from H^p(S^{2m-1}) to L^p(S^{2m-1}) for all p --> (1,infinity). We also show that the Bochner-Riesz conjecture is true when restricted to cylindrically symmetric functions on R^{n-1} times R.

Yong-Geun Oh

In this paper, we first develop a mini-max theory of the action functional over the semi-infinite cycles via the chain level Floer homology theory and construct spectral invariants of Hamiltonian diffeomorphisms on arbitrary compact symplectic manifold (M,omega). To each given time dependent Hamiltonian function H and quantum cohomology class 0 not equal a e

I. Coanda, A. Tikhomirov, G. Trautmann

We prove that the space of mathematical instantons with second Chern class 5 over ${\mathbb P}_3$ is smooth and irreducible. Unified and simple proofs for the same statements in case of second Chern class $\leq 4$ are contained.

Eckart Viehweg, Kang Zuo

Let f:X-->Y be a semi-stable family of complex abelian varieties over a curve Y of genus q, and smooth over the complement of s points. If F(1,0) denotes the non-flat (1,0) part of the corresponding variation of Hodge structures, the Arakelov inequalities say that 2deg(F(1,0)) is bounded from above by g=rank(F(1,0))(2q-2+s). We show that for s>0 families rea

Anna Lachowska

Using the quantum Fourier transform F, we describe the block decomposition and multiplicative structure of a subalgebra Z + F(Z) in the center of the small quantum group u_l at a root of unity. It contains the previously known subalgebra Z, which is isomorphic to the algebra of characters of finite dimensional modules over u_l. We prove that the intersection

Steven Buechler, Olivier Lessmann

Geometrical stability theory is a powerful set of model-theoretic tools that can lead to structural results on models of a simple first-order theory. Typical results offer a characterization of the groups definable in a model of the theory. The work is carried out in a universal domain of the theory (a saturated model) in which the Stone space topology on ul

N. Aizawa, F. J. Herranz, J. Negro, M. A. del Olmo

A new twisted deformation, U_z(so(4,2)), of the conformal algebra of the (3+1)-dimensional Minkowskian spacetime is presented. This construction is provided by a classical r-matrix spanned by ten Weyl-Poincare generators, which generalizes non-standard quantum deformations previously obtained for so(2,2) and so(3,2). However, by introducing a conformal null-

J. Alexandre, N. E. Mavromatos, Sarben Sarkar

Starting from N=1 scalar supermultiplets in 2+1 dimensions, we build explicitly the composite superpartners which define a N=2 superalgebra induced by the initial N=1 supersymmetry. The occurrence of this extension is linked to the topologically conserved current out of which the composite superpartners are constructed.

Carlos Castro

Based on the old results of Cho, Soh, Park and Yoon, it is shown how higher m + n dimensional pure gravitational actions restricted to AdS_m times S^n backgrounds admit a holographic reduction to a lower m-dimensional Yang-Mills-like gauge theory of diffeomorphisms of S^n interacting with a charged non-linear sigma model plus boundary terms by a simple tunin

C. D. Fosco, F. A. Schaposnik

We present a non-perturbative regularization scheme for Quantum Field Theories which amounts to an embedding of the originally unregularized theory into a spacetime with an extra compactified dimensions of length L ~ Lambda^{-1} (with Lambda an ultraviolet cutoff), plus a doubling in the number of fields, which satisfy different periodicity conditions and ha

Ranjan Kumar Ghosh

We argue that Quantum Gravitation forces us to sum over metrics of all signatures.

Ozgur Sarioglu

Given the path of a point particle, one can relate its acceleration and, in general, its kinematics to the curvature scalars of its trajectory. Using this, a general Ansatz is made for the Yang Mills connection corresponding to a non-Abelian point source. The Yang Mills field equations are then solved outside the position of the point source under physically

B. Allanach, S. Kraml, W. Porod

We provide a comparison of the results of four SUSY mass spectrum calculations in mSUGRA: Isajet, SuSpect, SoftSusy, and SPheno. In particular, we focus on the high tan(beta) and focus point regions, where the differences in the results are known to be large.

Paul Stoler

Nucleon elastic and transition form factors at high momentum transfer -t are treated in terms of generalized parton distributions in a two-body framework. In this framework the high -t dependence of the form factors give information about the high k_perp, or short distance b_perp correlations of nucleon model wave functions. Applications are made to elastic

A. Del Fabbro, D. Treleani

A sizable rate of events where two pairs of b-quarks are produced contemporarily is foreseen at the CERN LHC, as a consequence of the large parton luminosity. At very high energies both single and the double parton scatterings contribute to the process, the latter mechanisms, although power suppressed, giving the dominant contribution to the integrated cross

D. Falcone

We discuss the impact of fermion mass matrices on some lepton number violating processes, namely baryogenesis via leptogenesis and neutrinoless double beta decay, and on some lepton flavor violating processes, namely radiative lepton decays in supersymmetric seesaw models.

P. Ball, V. M. Braun, N. Kivel

We develop a consistent technique for the calculation of real photon emission in hard exclusive processes, which is based on the background field formalism and allows a convenient separation of hard electromagnetic and soft hadronic components of the photon. The latter ones are related to matrix-elements of light-cone operators in the electromagnetic backgro

M. A. Perfilov, S. M. Troshin

We demonstrate that the explicit mass dependence of the exponent in the power--like energy behavior of the vector--meson production cross-section in the processes of virtual photon interactions with a proton gamma^*p --> Vp obtained in the off--shell extension of the approach based on unitarity is in a quantitative agreement with the high--energy HERA experi

Wojciech Krolikowski

A new explicit model of neutrino texture is presented, where in the overall 6x6 mass matrix the lefthanded and righthanded Majorana 3x3 components are diagonal with equal entries of opposite sign, while the Dirac 3x3 component is given as a diagonal hierarchical structure (possibly similar to the charged lepton and quark 3x3 mass matrices) deformed by the po

C. Michael

Lattice QCD can give direct information on OZI-violating contributions to mesons. Here we explore the contributions that split flavour singlet and non-singlet meson masses. I discuss in detail the spectrum and decays for scalar mesons (ie including glueball effects). I also review the status of hybrid mesons and their decays.

Bernd Gehrmann

As a computationally less costly test case for full QCD, we investigate an SU(3) Yang-Mills theory coupled to a bosonic spinor field. This theory corresponds to QCD with minus two quark flavors and is known as the bermion model. Our central object of interest is the step scaling function which describes the scale evolution of the running coupling in the Schr

B. Aubert, BABAR Collaboration

The B^0 -> D^*-a_1^+ branching fraction has been measured with data collected by the BABAR experiment in 1999 and 2000 corresponding to a total integrated luminosity of 20.6 fb^-1. Signal events have been selected using a partial reconstruction technique, in which only the a_1^+ and the slow pion (pi_s) from the D^*- decay are identified. A signal yield of 1

The BABAR Collaboration, B. Aubert

A preliminary determination of the first moment of the hadronic mass distribution <(M_X)^2 - bar{m_D}^2> in semileptonic B decays has been obtained as a function of the minimum lepton momentum, ranging from 0.9 to 1.6 GeV/c. The measurement is based on a new technique involving BBbar events in which one fully reconstructed B meson decays hadronically and the

The BABAR Collaboration, B. Aubert

We present a search for the decays B0->e+e-, B0->mu+mu-, and B0->emu in data collected at the Upsilon(4S) with the BABAR detector at the SLAC B Factory. Using a data set of 54.4 fb-1, we find no evidence for a signal and set the following preliminary upper limits at the 90% confidence level: B(B0->e+e-)< 3.3*10E-7, B(B0->mu+mu-) < 2.0*10E-7, and B(B0->emu) <

B. Aubert

We present preliminary results from a search for the rare, flavor-changing neutral current decays B to K l+ l- and B to K* l+ l-, where l+ l- is either an e+ e- or mu+ mu- pair. The data sample comprises (84.4 +- 0.9) X 10e6 upsilon(4S) to B B-bar decays (77.8 /fb) collected with the BaBar detector at the PEP-II B factory. For B to K l+ l-, we observe a sign

The BABAR Collaboration, B. Aubert

A preliminary result on the study of the inclusive electron spectrum in B -> X_u e nu decays above the kinematic limit for the dominant B -> X_c e nu transitions is presented. This study is performed at the PEP-II asymmetric B Factory, where B meson pairs are produced in the decay of the Upsilon(4S) resonance. For the electron momentum range of 2.3 - 2.6 GeV

B. Aubert, BABAR Collaboration

We present a preliminary measurement of the branching fraction for B to rho e nu and of the CKM matrix element |Vub| using approximately 55 million B Bbar meson pairs collected with the BABAR detector. Using isospin relations for several modes we find BF(B0 to rho- e+ nu) = (3.39+-0.44+-0.52+-0.60)x10^(-4) and |Vub| = (3.69+-0.23+-0.27+0.40-0.59)x10^(-3). Th

The BABAR Collaboration, B. Aubert

We present measurements of the decays B0->Ds(*)+D*-, using data recorded by the BABAR detector in 1999 and 2000, consisting of 20.8 fb^-1. The analysis is conducted with a partial reconstruction technique, in which only the Ds(*)+ and the soft pion from the D*- decay are reconstructed. From the observed rates, we measure the branching fractions BR(B0->Ds+D*-

R. Ammar, CLEO Collaboration

Using the CLEO detector at the Cornell Electron Storage Ring, we have observed the Omega_c (css ground state) in the decay Omega_c -> Omega- e+ nu. We find a signal of 11.4 +- 3.8 (stat) events. The probability that we have observed a background fluctuation is 7.6 x 10-5. We measure BF(Omega_c -> Omega- e+ nu) x sigma(e+ e- -> Omega_c X) = (42.2 +- 14.1 (sta

B. Aubert, BaBar Collaboration

We present a preliminary determination of the inclusive branching fraction for the rare radiative penguin transition B -> X_{s} gamma. The measurement is based on a data sample of 60 million BB pairs collected between 1999 and 2001 with the BaBar detector at the PEPII asymmetric-energy e+e- B Factory at SLAC. We study events containing a high-energy photon f

Ronald W. Hellings, Thomas A. Moore

The nonlinear aspect of gravitational wave generation that produces power at harmonics of the orbital frequency, above the fundamental quadrupole frequency, is examined to see what information about the source is contained in these higher harmonics. We use an order (4/2) post-Newtonian expansion of the gravitational wave waveform of a binary system to model

Eric Poisson

We consider a situation in which two metrics are joined at a null hypersurface. It often occurs that the union of the two metrics gives rise to a Ricci tensor that contains a term proportional to a Dirac delta-function supported on the hypersurface. This singularity is associated with a thin distribution of matter on the hypersurface, and following Barrabes

Lorenzo Iorio

According to very recent developments of the LARES mission, which would be devoted to the measurement of the general relativistic Lense--Thirring effect in the gravitational field of the Earth with Satellite Laser Ranging, it seems that the LARES satellite might be finally launched in a polar, low--altitude orbit by means of a relatively low--cost rocket. Th

Gyula Fodor, Zoltán Perjés, Michael Bradley

The slow-rotation approximation of Hartle is developed to a setting where a charged rotating fluid is present. The linearized Einstein-Maxwell equations are solved on the background of the Reissner-Nordstrom space-time in the exterior electrovacuum region. The theory is put to action for the charged generalization of the Wahlquist solution found by Garcia. T

Henryk Fuks, Anna T. Lawniczak, Stanislav Volkov

We investigate individual packet delay in a model of data networks with table-free, partial table and full table routing. We present analytical estimation for the average packet delay in a network with small partial routing table. Dependence of the delay on the size of the network and on the size of the partial routing table is examined numerically. Conseque

François Bry

The model theory of a first-order logic called N^4 is introduced. N^4 does not eliminate double negations, as classical logic does, but instead reduces fourfold negations. N^4 is very close to classical logic: N^4 has two truth values; implications in N^4 are material, like in classical logic; and negation distributes over compound formulas in N^4 as it does

Diderik Batens

This paper concerns a goal directed proof procedure for the propositional fragment of the adaptive logic ACLuN1. At the propositional level, it forms an algorithm for final derivability. If extended to the predicative level, it provides a criterion for final derivability. This is essential in view of the absence of a positive test. The procedure may be gener

Jan Małuszyński, Aida Vitória

We show how definite extended logic programs can be used for defining and reasoning with rough sets. Moreover, a rough-set-specific query language is presented and an answering algorithm is outlined. Thus, we not only show a possible application of a paraconsistent logic to the field of rough sets as we also establish a link between rough set theory and logi

Guo-Qiang Zhang

This paper studies axioms for nonmonotonic consequences from a semantics-based point of view, focusing on a class of mathematical structures for reasoning about partial information without a predefined syntax/logic. This structure is called a default structure. We study axioms for the nonmonotonic consequence relation derived from extensions as in Reiter&#39

Michael J. Maher

Defeasible logic is an efficient logic for defeasible reasoning. It is defined through a proof theory and, until now, has had no model theory. In this paper a model-theoretic semantics is given for defeasible logic. The logic is sound and complete with respect to the semantics. We also briefly outline how this approach extends to a wide range of defeasible l

Ofer Arieli, Marc Denecker, Bert Van Nuffelen, Maurice Bruynooghe

In this paper we consider two points of views to the problem of coherent integration of distributed data. First we give a pure model-theoretic analysis of the possible ways to `repair&#39; a database. We do so by characterizing the possibilities to `recover&#39; consistent data from an inconsistent database in terms of those models of the database that exhib

Philippe Besnard, Torsten Schaub, Hans Tompits, Stefan Woltran

Signed systems were introduced as a general, syntax-independent framework for paraconsistent reasoning, that is, non-trivialised reasoning from inconsistent information. In this paper, we show how the family of corresponding paraconsistent consequence relations can be axiomatised by means of quantified Boolean formulas. This approach has several benefits. Fi

D. A. Bagrets, Yu. V. Nazarov

Full counting statistics (FCS) of charge transfer in mesoscopic systems has recently become a subject of significant interest, since it proves to reveal an important information about the system which can be hardly assessed by other means. While the previous research mostly addressed the FCS of non- interacting systems, the present paper deals with the FCS i

D. E. Feldman, Yuval Gefen

It is well known that while forward scattering has no effect on the conductance of one-dimensional systems, backscattering off a static impurity suppresses the current. We study the effect of a time-dependent point impurity on the conductance of a one-channel quantum wire. At strong repulsive interaction (Luttinger liquid parameter g<1/2), backscattering ren

Robert M. Konik

We consider transport through quantum dots with two tunneling paths. Interference between paths gives rise to Fano resonances exhibiting Kondo-like physics. In studying such quantum dots, we employ a generalized Anderson model which we argue to be integrable. The exact solution is non-perturbative in the tunneling strengths of both paths. By exploiting this

A. A. Zhukov, P. A. J. de Groot, V. V. Metlushko, B. Ilic

We study the interactions of the vortex lattice with a periodic square array of holes in a superconducting Nb film. Using high resolution magnetic field measurements of electrical losses, extremely narrow states with a magnetic field width reaching 1% of the matching field value are found at the commensurate points. They are accompanied by pronounced harmoni

J. Davidsen, R. Kapral

The influence of topological defects on phase synchronization and phase coherence in two-dimensional arrays of locally-coupled, nonidentical, chaotic oscillators is investigated. The motion of topological defects leads to a breakdown of phase synchronization in the vicinities of the defects; however, the system is much more phase coherent as long as the coup

Ana. L. C. Pereira, P. A. Schulz

The behavior of extended states is quantitatively analyzed for two dimensional lattice models. A levitation picture is established for both white-noise and correlated disorder potentials. In a continuum limit window of the lattice models we find simple quantitative expressions for the extended states levitation, suggesting an underlying universal behavior. O

Sudhansu S. Mandal, J. K. Jain

The activation energy measured in transport experiments in the fractional Hall regime corresponds to the energy required to create a far separated particle hole pair. We calculate, for several fractional quantum Hall states, the energy gaps for the excitation in which the excited composite fermion reverses its spin quantum number. Our results indicate that s

Sudhansu S. Mandal, Jainendra K. Jain

It is shown that Wen&#39;s effective theory correctly describes the Tomonaga-Luttinger liquid at the edge of a system of non-interacting composite fermions. However, the weak residual interaction between composite fermions appears to be a relevant perturbation. The filling factor dependence of the Tomonaga-Luttinger parameter is estimated for interacting com

T. J. da Silva, J. G. Moreira

We simulate a growth model with restricted surface relaxation process in d=1 and d=2, where d is the dimensionality of a flat substrate. In this model, each particle can relax on the surface to a local minimum, as the Edwards-Wilkinson linear model, but only within a distance s. If the local minimum is out from this distance, the particle evaporates through

G. E. Astrakharchik, S. Giorgini

We investigate the cross-over from three to one dimension in a Bose gas confined in highly anisotropic traps. By using Quantum Monte-Carlo techniques, we solve the many-body Schrodinger equation for the ground state and obtain exact results for the energy per particle and the mean square radii of the cloud in the transverse and longitudinal direction. Result

M. Kessler, W. Dieterich, A. Majhofer

Using an atom-vacancy exchange algorithm, we investigate the kinetics of the order-disorder transition in an fcc A_3B binary alloy model following a temperature quench from the disordered phase. We observe two clearly distinct ordering scenarios depending on whether the final temperature T_f falls above or below the ordering spinodal T_{sp}, which is deduced

Jordi Soriano, Jordi Ortin, Aurora Hernandez-Machado

We have studied the kinetic roughening of an oil--air interface in a forced imbibition experiment in a horizontal Hele--Shaw cell with quenched disorder. Different disorder configurations, characterized by their persistence length in the direction of growth, have been explored by varying the average interface velocity v and the gap spacing b. Through the ana

S. Cocco, J. F. Marko, R. Monasson

Recent experiments on unzipping of RNA helix-loop structures by force have shown that about 40-base molecules can undergo kinetic transitions between two well-defined `open&#39; and `closed&#39; states, on a timescale = 1 sec [Liphardt et al., Science 297, 733-737 (2001)]. Using a simple dynamical model, we show that these phenomena result from the slow kine

I. S. Manida, Yu. M. Pis&#39;mak

We study a simple model of the stochastic information filtering, in a randomly organized information system. For simplest versions of the model it appears to be possible to describe the filtering dynamics in terms of the master equations. Exact analytical results for these equations and results of numerical investigation of the dynamical features of the filt

E. E. Krasovskii, W. Schattke, V. N. Strocov, R. Claessen

A combined experimental and theoretical study of very-low-energy electron diffraction at the (0001) surface of 2H-NbSe2 is presented. Electron transmission spectra have been measured for energies up to 50 eV above the Fermi level with k|| varying along the GammaK line of the Brillouin zone. Ab initio calculations of the spectra have been performed with the e

A. K. Rajagopal, R. W. Rendell, Sumiyoshi Abe

The Kullback-Leibler inequality is a way of comparing any two density matrices. A technique to set up the density matrix for a physical system is to use the maximum entropy principle, given the entropy as a functional of the density matrix, subject to known constraints. In conjunction with the master equation for the density matrix, these two ingredients all

S. Blawid, A. Deppeler, A. J. Millis

We propose a new semiclassical approach based on the dynamical mean field theory to treat the interactions of electrons with local lattice fluctuations. In this approach the classical (static) phonon modes are treated exactly whereas the quantum (dynamical) modes are expanded to second order and give rise to an effective semiclassical potential. We determine

Navdeep Bajwa, Alka Ingale, D. K. Avasthi, Ravi Kumar

Modification induced by 110 MeV Ni ion irradiated thin film samples of C60 on Si and quartz substrates were studied at various fluences. The pristine and irradiated samples were investigated using Raman spectroscopy, electrical conductivity and optical absorption spectroscopy. The Raman data and band gap measurements indicate that swift ions at low fluences

D. Paolotti, C. Cattuto, U. Marini Bettolo Marconi, A. Puglisi

Motivated by recent experiments we have carried out an Event Driven computer simulation of a diluted binary mixture of granular particles vertically vibrated in the presence of gravity. The simulations not only confirm that the kinetic energies of the two species are not equally distributed, as predicted by various theoretical models, but also seem to reprod

A. Crépieux, P. Bruno

In heterogeneous system, the correspondence between calculated and measured quantities, such as the conductivity or the resistivity, is not obvious since the former ones are local quantities whereas the latter ones are often average values over the sample. In this report, we show explicitly how the correspondence can be done in the case of magnetic multilaye

I. Shvarchuck, Ch. Buggle, D. S. Petrov, K. Dieckmann

We report the formation of Bose-Einstein condensates into non-equilibrium states. Our condensates are much longer than equilibrium condensates with the same number of atoms, show strong phase fluctuations, and have a dynamical evolution similar to that of quadrupole shape oscillations of regular condensates. The condensates emerge in elongated traps as the r

Dietrich Stauffer

In the Sznajd model of 2000, a pair of neighbouring agents on a square lattice convinces its six neighbours of the pair opinion iff the two agents of the pair share the same opinion. Now we replace the usual random sequential updating rule by simultaneous updating and find that this change makes a complete consenus much more difficult. The larger the lattice

T. M. Buehler, D. J. Reilly, R. Brenner, A. R. Hamilton

The single electron transistor (SET) is a prime candidate for reading out the final state of a qubit in a solid state quantum computer. Such a measurement requires the detection of sub-electron charge motion in the presence of random charging events. We present a detection scheme where the signals from two SETs are cross-correlated to suppress unwanted artif

Pekka Koskinen, Ulrich Hohenester

We present a theoretical analysis of four-wave mixing in coupled quantum dots subject to inhomogeneous broadening. For the biexciton transitions a clear signature of interdot-coupling appears in the spectra. The possibility of experimental observation is discussed.

Kazuo Hida

The ground state phase transitions in the distorted S=1 kagome Heisenberg antiferromagnet (KHAF) with single-site anisotropy D are studied by the numerical exact diagonalization method. For strong easy plane anisotropy, the hexgonal singlet solid (HSS) ground state of the uniform KHAF is destroyed and large-D state is realized. The quantum phase transition b