November 2005 arXiv papers — page 33

Raffaele Romano, Domenico D'Alessandro

We prove that the environment induced entanglement between two non interacting, two-dimensional quantum systems S and P can be used to control the dynamics of S by means of the initial state of P. Using a simple, exactly solvable model, we show that both accessibility and controllability of S can be achieved under suitable conditions on the interaction of S

Wissam Abdel Samad, Roy Ghandour, Mohamad Nabil Hajj Chehade

In this paper, we will introduce the quantum circuit simulator we developed in C++ environment. We devise a novel method for efficient memory handling using linked list structures that enables us to simulate a quantum circuit of up to 20 qubits in a reasonable time. Our package can simulate the activity of any quantum circuit constructed by the user; it will

Nelson R. F. Braga, Rafael D'Andrea

We study the Schrodinger equation for one-electron atoms in space-times with d >= 4 spatial dimensions where the Gauss law is assumed to be valid. It is shown that there are no normalizable wave functions corresponding to bound states. The consistency with the classical limit is discussed.

Alessandro Sergi

The symplectic structure of quantum commutators is first unveiled and then exploited to introduce generalized non-Hamiltonian brackets in quantum mechanics. It is easily recognized that quantum-classical systems are described by a particular realization of such a bracket. In light of previous work, this introduces a unified approach to classical and quantum-

R. W. Robinett

A simple model wavefunction, consisting of a linear combination of two free-particle Gaussians, describes many of the observed features seen in the interactions of two isolated Bose-Einstein condensates as they expand, overlap, and interfere. We show that a simple extension of this idea can be used to predict the qualitative time-development of a single expa

Andrei Khrennikov

We show that QM can be represented as a natural projection of a classical statistical model on the phase space $Ω= H\times H,$ where $H$ is the real Hilbert space. Statistical states are given by Gaussian measures on $Ω$ having zero mean value and dispersion of very small magnitude $α$ (which is considered as a small parameter of the model). Such statistical

Marco Lucamarini

I present an eavesdropping on the protocol proposed by W.-H. Kye, et al. [Phys. Rev. Lett. 95, 040501 (2005)]. I show how an undetectable Eve can steal the whole information by labeling and then measuring the photons prepared by the user Alice.

Thomas F. Jordan, Anil Shaji, E. C. G. Sudarshan

Lorentz transformations of spin density matrices for a particle with positive mass and spin 1/2 are described by maps of the kind used in open quantum dynamics. They show how the Lorentz transformations of the spin depend on the momentum. Since the spin and momentum generally are entangled, the maps generally are not completely positive and act in limited do

S. Ritter, J. Odenheimer, D. W. Heermann, F. Bantignies

The conditions of the chromosomes inside the nucleus in the Rabl configuration have been modelled as self-avoiding polymer chains under restraining conditions. To ensure that the chromosomes remain stretched out and lined up, we fixed their end points to two opposing walls. The numbers of segments $N$, the distances $d_1$ and $d_2$ between the fixpoints, and

I. Yang, B. Kahng

Online auctions have expanded rapidly over the last decade and have become a fascinating new type of business or commercial transaction in this digital era. Here we introduce a master equation for the bidding process that takes place in online auctions. We find that the number of distinct bidders who bid $k$ times, called the $k$-frequent bidder, up to the $

S. Gordienko, T. Baeva, A. Pukhov

It is shown that plasma-based optics can be used to guide and focus highly divergent laser-generated ion beams. A hollow cylinder is considered, which initially contains a hot electron population. Plasma streaming toward the cylinder axis maintains a focusing electrostatic field due to the positive radial pressure gradient. The cylinder works as thick lens,

V. O. Nesterenko, P. -G. Reinhard, T. Halfmann, L. I. Pavlov

A simple scheme of population and detection of low-lying electronic quadrupole modes in free small deformed metal clusters is proposed. The scheme is analyzed in terms of the TDLDA (time-dependent local density approximation) calculations. As test case, the deformed cluster $Na^+_{11}$ is considered. Long-living quadrupole oscillations are generated via reso

S. V. Akulinichev, V. S. Klenov, L. V. Kravchuk, S. G. Lebedev

High radiation hardness, chemical resistance, high temperature operation capabilities stimulate a growing interest to use diamond materials as detectors of ionizing radiation. Samples of CVD-diamond materials in sizes 12 square mm and 4 square mm with thickness from 50 microns up to 500 microns have been grown in INR RAS using a DC glow discharge in a mixtur

Jozsef Garai

The work function is embedded in the equation describing the relationship between the constant volume and constant pressure heat capacities. The modification of the work function results that the relationship between these quantities must be changed accordingly. Using the newly derived work functions of elastic solids the description of the heat capacities a

Chunguang Du, Hongyi Chen, Shiqun Li

A scheme of left-handed metamaterial (LHM) composed of superconducting quantum interference devices (SQUIDs) and conducting wires is proposed. The permeability of a probe field can be smoothly tuned over a wide range with another electromagnetic (coupling) field due to quantum interference effect. Similar to electromagnetically induced transparency (EIT) of

Claudio Conti

The dynamics of several light filaments (spatial optical solitons) propagating in an optically nonlinear and non-local random medium is investigated using the paradigms of the physics of complexity. Cluster formation is interpreted as a dynamic phase transition. A connection with the random matrices approach for explaining the vibrational spectra of an ensem

M. J. Ison, C. O. Dorso

In this short communication we address the problem of reducibility in a highly excited Lennard-Jones system. We show that the probability of emitting $n$ fragments can be described in terms of a single probability through the binomial expression. However, the Arrhenius law does not hold and the process can be viewed as a mixture of sequential and simultaneou

V. N. Pomerantsev, V. P. Popov

The Coulomb deexcitation of $(πp)$ atom in collisions with the hydrogen atom has been studied in the fully quantum mechanical close-coupling approach for the first time. The total Coulomb deexcitation cross-sections of $nl\to n'l'$ transitions and $l$-averaged cross-sections are calculated for $n=3 - 8$ and at the relative energies $E=0.01 - 100$ eV.

V. Tvaskis, J. Arrington, M. E. Christy, R. Ent

The effects of two-photon exchange corrections, suggested to explain the difference between measurements of the proton elastic electromagnetic form factors using the polarization transfer and Rosenbluth techniques, have been studied in elastic and inelastic scattering data. Such corrections could introduce epsilon-dependent non-linearities in inelastic Rosen

A. N. Sissakian, A. S. Sorin, M. K. Suleymanov, V. D. Toneev

A physical program is formulated for new facilities opening in Dubna for acceleration of heavy ions with an energy up to 5 AGeV.

V. A. Bondarenko, J. Honzatko, V. A. Khitrov, A. M. Sukhovoj

Reliable information on level density and radiative strength functions for the excitation energy region with density of excited states more than 100 levels per 1 MeV and higher can be obtained now only by its model-free extraction from intensities of two-step cascades proceeding between compound states and few low-lying levels. Full model-free determination

J. C. González-Avella, M. G. Cosenza, K. Tucci

We study the effect of mass media, modeled as an applied external field, on a social system based on Axelrod's model for the dissemination of culture. The numerical simulations show that the system undergoes a nonequilibrium phase transition between an ordered phase (homogeneous culture) specified by the mass media and a disordered (culturally fragmented

Metod Saniga, Michel Planat

The basic combinatorial properties of a complete set of mutually unbiased bases (MUBs) of a q-dimensional Hilbert space H\_q, q = p^r with p being a prime and r a positive integer, are shown to be qualitatively mimicked by the configuration of points lying on a proper conic in a projective Hjelmslev plane defined over a Galois ring of characteristic p^2 and

Masao Hirokawa

We mathematically study the infrared catastrophe for the Hamiltonian of Nelson's model when it has the external potential in a general class. For the model, we prove the pull-through formula on ground states in operator theory first. Based on this formula, we show both non-existence of any ground state and divergence of the total number of soft bosons.

Radford M. Neal

Ratios of normalizing constants for two distributions are needed in both Bayesian statistics, where they are used to compare models, and in statistical physics, where they correspond to differences in free energy. Two approaches have long been used to estimate ratios of normalizing constants. The `simple importance sampling' (SIS) or `free energy perturb

Sylvie Monniaux

Navier-Stokes equations are investigated in a functional setting in 3D open sets, bounded or not, without assuming any regularity of the boundary. The main idea is to find a correct definition of the Stokes operator in a suitable Hilbert space of divergence-free vectors and apply the Fujita-Kato method, a fixed point procedure, to get a local strong solution

Michael McCooey

We consider locally linear Z_p x Z_p actions on the four-sphere. We present simple constructions of interesting examples, and then prove that a given action is concordant to its linear model if and only if a single surgery obstruction taking to form of an Arf invariant vanishes. We discuss the behavior of this invariant under various connected-sum operations

Karen Acquista

We give a criterion for the cohomological dimension of a field, involving norm maps on Milnor K-theory; this criterion was originally formulated by Kato. The theorem we prove is a generalization of a theorem in Serre's book on Galois cohomology.

Antoine Mellet, Alexis F. Vasseur

We consider the compressible Navier-Stokes equation with density dependent viscosity coefficients, focusing on the case where those coefficients vanish on vacuum. We prove the stability of weak solutions both in the torus and in the whole space in dimension 2 and 3. The pressure is given by p=rho^gamma, and our result holds for any gamma>1. In particular, we

Yonina C. Eldar, Ewa Matusiak, Tobias Werther

In this paper we develop constructive invertibility conditions for the twisted convolution. Our approach is based on splitting the twisted convolution with rational parameters into a finite number of weighted convolutions, which can be interpreted as another twisted convolution on a finite cyclic group. In analogy with the twisted convolution of finite discr

K. Slooten

Recently Delorme and Opdam have generalized the theory of R-groups towards affine Hecke algebras with unequal labels. We apply their results in the case where the affine Hecke algebra is of type B, for an induced discrete series representation with real central character. We calculate the R-group of such an induced representation, and show that it decomposes

Jean-Christophe Novelli, Jean-Yves Thibon

We introduce a graded Hopf algebra based on the set of parking functions (hence of dimension (n+1)^{n-1} in degree n). This algebra can be embedded into a noncommutative polynomial algebra in infinitely many variables. We determine its structure, and show that it admits natural quotients and subalgebras whose graded components have dimensions respectively gi

P. E. Frenkel

We give formulae relating the value of an irreducible character of a classical group at a matrix to entries of powers of the matrix. This yields a far-reaching generalization of a result of J. L. Cisneros-Molina concerning the $GL_2$ case.

Zhiqiang Xu

Based on discrete truncated powers, the beautiful Popoviciu's formulation for restricted integer partition function is generalized. An explicit formulation for two dimensional multivariate truncated power functions is presented. Therefore, a simplified explicit formulation for two dimensional vector partition functions is given. Moreover, the generalized

Christian Voigt

We introduce and study the concept of a bornological quantum group. This generalizes the theory of algebraic quantum groups in the sense of van Daele from the algebraic setting to the framework of bornological vector spaces. Working with bornological vector spaces, the scope of the latter theory can be extended considerably. In particular, the bornological t

Teodora Liliana Dinu

We study the boundary value problem $-{\rm div}((|\nabla u|^{p\_1(x) -2}+|\nabla u|^{p\_2(x)-2})\nabla u)=f(x,u)$ in $Ω$, $u=0$ on $\partialΩ$, where $Ω$ is a smooth bounded domain in $\RR^N$. We focus on the cases when $f\_\pm (x,u)=\pm(-λ|u|^{m(x)-2}u+|u|^{q(x)-2}u)$, where $m(x):=\max\{p\_1(x),p\_2(x)\} < q(x) < \frac{N\cdot m(x)}{N-m(x)}$ for any $x\in\b

Teodora Liliana Dinu

We establish the existence of an entire solution for a class of stationary Schrödinger systems with subcritical discontinuous nonlinearities and lower bounded potentials that blow-up at infinity. The proof is based on the critical point theory in the sense of Clarke and we apply Chang&#39;s version of the Mountain Pass Lemma for locally Lipschitz functionals

Robert M. Guralnick, Martin Lorenz

We present a new proof of a theorem of Schur&#39;s determining the least common multiple of the orders of all finite groups of complex $n \times n$-matrices whose elements have traces in the field of rational numbers. The basic method of proof goes back to Minkowski and proceeds by reduction to the case of finite fields. For the most part, we work over an ar

Euisung Park

Let $X \subset ¶^r$ be a nondegenerate projective variety and let $ν_{\ell} : ¶^r \to ¶^N$ be the $\ell$-th Veronese embedding. In this paper we study the higher normality, defining equations and syzygies among them for the projective embedding $ν_{\ell} (X) \subset ¶^N$. We obtain that for a very ample line bundle $L \in {Pic}X$ such that $X \subset ¶H^0 (X

Seppo I Hiltunen

This note aims to clarify the interrelations of certain inequivalently defined Banach spaces denoted by C^i(\barΩ) for a natural number i and a bounded open set Ω. We give some sufficient conditions for the equality of these spaces, and present examples to show that the spaces indeed can be unequal for Ωhaving irregular boundary.

Andreas Fring

We consider non-Hermitian but PT-symmetric extensions of Calogero models, which have been proposed by Basu-Mallick and Kundu for two types of Lie algebras. We address the question of whether these extensions are meaningful for all remaining Lie algebras (Coxeter groups) and if in addition one may extend the models beyond the rational case to trigonometric, h

A. Gorsky, M. B. Voloshin

We revisit the problem of decay of a metastable vacuum induced by the presence of a particle. For the bosons of the `master field&#39; the problem is solved in any number of dimensions in terms of the spontaneous decay rate of the false vacuum, while for a fermion we find a closed expression for the decay rate in (1+1) dimensions. It is shown that in the (1+

M. Chaichian, K. Nishijima, A. Tureanu

Noncommutative coordinates are decomposed into a sum of geometrical ones and a universal quantum shift operator. With the help of this operator, the mapping of a commutative field theory into a noncommutative field theory (NCFT) is introduced. A general measure for the Lorentz-invariance violation in NCFT is also derived.

Hartmut Pilkuhn

For relativistic closed systems, an operator is explained which has as stationary eigenvalues the squares of the total cms energies, while the wave function has only half as many components as the corresponding Dirac wave function. The operator&#39;s time dependence is generalized to a Klein-Gordon equation. It ensures relativistic kinematics in radiative de

H. Q. Lu, Z. G. Huang, W. Fang, P. Y. Ji

In this paper, we consider a quantum model of gravitation interacting with a Born-Infeld(B-I) type scalar field $ϕ$. The corresponding Wheeler-Dewitt equation can be solved analytically for both very large and small cosmological scale factor. In the condition that small cosmological scale factor tend to limit, the wave function of the universe can be obtaine

Raul Rabadan, Andreas Ringwald, Kris Sigurdson

Recently, the PVLAS collaboration has reported an anomalously large rotation of the polarization of light in the presence of a magnetic field. As a possible explanation they consider the existence of a light pseudoscalar particle coupled to two photons. In this note, we propose a method of independently testing this result by using a high-energy photon regen

Rainer J. Fries, Joseph I. Kapusta, Yang Li

We discuss a model for the energy distribution and the early space-time evolution of a heavy ion collision. We estimate the gluon field generated in the wake of hard processes and through primordial fluctuations of the color charges in the nuclei. Without specifying the dynamical mechanism of thermalization we calculate the energy momentum tensor of the foll

Sanghyeon Chang, C. S. Kim, Masahiro Yamaguchi

The warped bulk standard model has been studied in the Randall-Sundrum background on $S^1/\Z\times\Z&#39;$ interval with the bulk gauge symmetry $SU(3)\times SU(2)_L\times SU(2)_R\times U(1)_{B-L}$. With the assumption of no large cancellation between the fermion flavor mixing matrices, we present a simple analytic method to determine the bulk masses of stan

Bjorn O Lange

A leading-power factorization formula for weight functions relating the B to Xs gamma photon spectrum to arbitrary partial decay rates in B to Xu l nu is derived. These weight functions are independent of the hadronic shape function and allow for the determination of V_{ub} in a model-independent way. We calculate the weight function in renormalization-group

S. M. Barr, Bumseok Kyae, Qaisar Shafi

It is shown that in SO(10) and SU(5) models having a $U(1)_R$ symmetry, the requirement of breaking the unified group to the Standard Model leads to flat directions in the scalar potential. These can lead to a ``cosmological modulus problem&#34;. This is relevant to grand unified models of inflation, where $U(1)_R$ symmetries are often used to insure the fla

F. Kleefeld

A new crossing symmetric unitarization scheme conveniently applied to meson-meson and meson-baryon scattering amplitudes is shortly proposed which can be not only used by theoreticians to unitarize arbitrary theoretical reaction amplitudes resulting from phenomenological Lagrangeans for mesons and baryons, yet also by experimentalists to generate realistic u

R. Peschanski

Central diffractive production of the Higgs boson has recently received much attention as a potentially interesting production mode at the LHC. We shall review some of the wishes and realities encountered in this field. Theoretical open problems of diffractive dynamics are involved in making accurate predictions for the LHC, among which the most crucial is u

Dieter Schildknecht

Historically vector-meson physics arose along two different paths to be reviewed in Sections 1 and 2. In Section 3, the phenomenological consequences will be discussed with an emphasis on those aspects of the subject matter relevant in present-day discussions on deep inelastic scattering in the diffraction region of low values of the Bjorken variable.

D. Schildknecht

The energy dependence of the virtual photoabsorption cross section in deep inelastic scattering (DIS) at low $x = Q^2/W^2 < 0.1$ may be described in terms of the saturation scale that in our approach depends on the energy, $Λ^2_{sat} = Λ^2_{sat} (W^2)$. We briefly summarize our recent findings that allow us to predict the exponent $C_2$ of $Λ^2_{sat} (W^2) \

E. Accomando, A. Kaiser

We have analysed the production of WW and WZ vector-boson pairs at the LHC. These processes give rise to four-fermion final states, and are particularly sensitive to possible non-standard trilinear gauge-boson couplings. We have studied the interplay between the influence of these anomalous couplings and the effect of the complete logarithmic electroweak O(α

Matthias Buchler

I calculate the leading logarithmic contributions up to two-loop order of the octet part of the K -> pi pi amplitude. This sector of the weak chiral Lagrangian is believed to be the main source of the enhancement of the I=0 relative to the I=2 K -> pi pi amplitude, the so-called Delta I = 1/2 rule. I discuss the procedure of chiral extrapolations of lattice

Adam P. Szczepaniak, Pawel Krupinski

We compute the energy of the ground state and a low lying excitation of the gluonic field in the presence of static quark -anti-quark ($\qq$) sources. We show that for separation between the sources less then a few fm the gluonic ground state of the static $\qq$ system can be well described in terms of a mean field wave functional with the excited states cor

Francesco Knechtli

We present a determination of the strange quark mass using lattice QCD. Particular focus is put on the definition and renormalization of the mass. The latter is done non-perturbatively, using a recursive finite-size scaling technique. The hadronic regime of QCD, where the kaon mass is used as input of the calculation, is connected with the perturbative regim

Dariusz Prorok

The transverse energy and charged particle multiplicity at midrapidity and their ratio are evaluated in a statistical model with the longitudinal and transverse flows for different centrality bins at RHIC at $\sqrt{s_{NN}}=130$ and 200 GeV. Full description of decays of hadron resonances is applied in these estimations. The predictions of the model at the fr

A. Abulencia

We measure the branching fraction of the top quark to longitudinally and right-handed polarized $W$ bosons, $F_0$ and $F_+$, using approximately 200 pb$^{-1}$ of $\bar{p}p$ collisions collected by the CDF II detector. We analyze two quantities sensitive to the $W$ helicity: the invariant mass of the charged lepton and the bottom-quark jet in the decay $t\to

M. Ablikim

Using 58 million $J/ψ$ events taken with the BESII detector, a search for $eta_{c}$ CP violating decays into $ππ$ and $\bar{K}K$ has been performed. No clear $eta_{c}$ is observed, and upper limits for $B(eta_{c}->ππ)$and $B(eta_{c}->\bar{K} K)$ are given at the 90% confidence level, $B(J/ψ->γη_{c})\times B(eta_{c}->π^{+}π^{-})<1.1\times 10^{-5}$ , $B(J/ψ->γ

Lorenzo Iorio

In this letter we work out the secular precession of the spin of a gyroscope in geodesic motion around a central mass in the framework of the Dvali-Gabadadze-Porrati multidimensional gravity model. Such an effect, which depends on the mass of the central body and on the orbit radius of the gyroscope, contrary to the precessions of the orbital elements of the

P. D. D&#39;Eath

The canonical approach to Riemannian quantum gravity is reviewed with reference to local supersymmetry, to the classical boundary-value problem arising from the Hartle-Hawking quantum state, and particularly for (anti-)self-dual geometries. Two examples of the boundary-value problem for the Einstein equations, possibly with a cosmological constant Λ, are tre

Zdzislaw A. Golda, Andrzej Woszczyna, Karolina Zawada

Under an appropriate change of the perturbation variable Lifshitz-Khalatnikov propagation equations for the scalar perturbation reduce to d&#39;Alembert equation. The change of variables is based on the Darboux transform.

Mei Chen, Oliver M. Collins

This paper introduces a new trellis pruning method which uses nonlinear convolutional coding for peak-to-average power ratio (PAPR) reduction of filtered QPSK and 16-QAM modulations. The Nyquist filter is viewed as a convolutional encoder that controls the analog waveforms of the filter output directly. Pruning some edges of the encoder trellis can effective

Mei Chen, Teng Li, Oliver M. Collins

We propose a computationally efficient multilevel coding scheme to achieve the capacity of an ISI channel using layers of binary inputs. The transmitter employs multilevel coding with linear mapping. The receiver uses multistage decoding where each stage performs a separate linear minimum mean square error (LMMSE) equalization and decoding. The optimality of

Stanislav Bulygin

In this paper we studied generalization of Hermitian function field proposed by A.Garcia and H.Stichtenoth. We calculated a Weierstrass semigroup of the point at infinity for the case q=2, r>=3. It turned out that unlike Hermitian case, we have already three generators for the semigroup. We then applied this result to codes, constructed on generalized Hermit

Martin Ziegler

For a linearly recurrent vector sequence P[n+1] = A(n) * P[n], consider the problem of calculating either the n-th term P[n] or L<=n arbitrary terms P[n_1],...,P[n_L], both for the case of constant coefficients A(n)=A and for a matrix A(n) with entries polynomial in n. We improve and extend known algorithms for this problem and present new applications for i

Yang Li Hector Yee

We present a method to accelerate global illumination computation in dynamic environments by taking advantage of limitations of the human visual system. A model of visual attention is used to locate regions of interest in a scene and to modulate spatiotemporal sensitivity. The method is applied in the form of a spatiotemporal error tolerance map. Perceptual

Constantino Tsallis

Critiques presented by P. Grassberger in Phys. Rev. Lett. 95, 140601 (2005) are addressed.

Gil Refael, Eugene Demler, Yuval Oreg, Daniel S. Fisher

The interplay of quantum fluctuations and dissipation in chains of mesoscopic superconducting grains is analyzed, and the results are also applied to nanowires. It is shown that in 1-d arrays of resistively shunted Josephson junctions, the superconducting-normal charge relaxation within the grains plays an important role. At zero temperature, two superconduc

Dengke Yu, Matthias Scheffler, Mats Persson

We show from density-functional calculations that Pb(100) thin films exhibit quantum size effect with a bilayer periodicity in film energies, film relaxations, and work functions, which originate from different symmetry of the stacking geometry of odd and even layer films. The bilayer periodicity of the film energy is argued to survive on a semiconductor sub

Michael Hermele, Gil Refael, Matthew P. A. Fisher, Paul M. Goldbart

A system comprising two superconducting thin films connected by a point contact is considered. The contact resistance is calculated as a function of temperature and film geometry, and is found to vanish rapidly with temperature, according to a universal, nearly activated form, becoming strictly zero only at zero temperature. At the lowest temperatures, the a

Bin Liu, J. Goree

The Stokes-Einstein relation, relating the diffusion and viscosity coefficients D and eta, is tested in two dimensions. An equilibrium molecular-dynamics simulation was used with a Yukawa pair potential. Regimes are identified where motion is diffusive and D is meaningful. The Stokes-Einstein relation, D ~ kT, was found to be violated near the disordering tr

O. Bénichou, M. Coppey, M. Moerau, G. Oshanin

We study kinetics of diffusion-limited catalytically-activated $A + B \to B$ reactions taking place in three dimensional systems, in which an annihilation of diffusive $A$ particles by diffusive traps $B$ may happen only if the encounter of an $A$ with any of the $B$s happens within a special catalytic subvolumen, these subvolumens being immobile and uniform

Jung-Ren Huang

A new model is proposed to explain coiling of myelins composed of fluid bilayers. This model allows the constituent bilayer cylinders of a myelin to be non-coaxial and the bilayer lateral tension to vary from bilayer to bilayer. The calculations show that a myelin would bend or coil to lower its free energy when the bilayer lateral tension is sufficiently la

Artur Sowa

A nonlinear single-particle model is introduced, which captures the characteristic of systems in the quantum Hall regime. The model entails the magnetic Shrödinger equation with spatially variable magnetic flux density. The distribution of flux is prescribed via the postulates of the mesoscopic mechanics (MeM) introduced in my previous articles [cf. J. Phys.

M. T. Mercaldo, J-Ch. Anglès d&#39;Auriac, F. Iglói

We study the effect of varying strength, $δ$, of bond randomness on the phase transition of the three-dimensional Potts model for large $q$. The cooperative behavior of the system is determined by large correlated domains in which the spins points into the same direction. These domains have a finite extent in the disordered phase. In the ordered phase there

Dario F. Martinez, Rafael A. Molina

We study the localization properties of disordered semiconductor superlattices driven by ac-fields. The localization length of the electrons in the superlattice increases when the frequency of the driving field is smaller than the miniband width. We show that there is an optimal value of the amplitude of the driving field for which the localization length of

A. R. Massih, L. O. Jernkvist

The Langer-Schwartz equations for precipitation are formulated to calculate nucleation, growth and coarsening of second phase precipitates under non-isothermal situations. A field-theoretic steady-state nucleation rate model is used in the analysis. The field-theoretic nucleation rate is compared with the classical nucleation rate relation derived from the F

David L Cheung, Friederike Schmid

The effect of rough walls on the phase behaviour of a confined liquid crystal (LC) fluid is studied using constant pressure Monte Carlo simulations. The LC is modelled as a fluid of soft ellipsoidal molecules and the rough walls are represented as a hard wall with a number of molecules randomly embedded in them. It is found that the isotropic-nematic (IN) tr

Martin W. Zwierlein, André Schirotzek, Christian H. Schunck, Wolfgang Ketterle

Whether it occurs in superconductors, helium-3 or inside a neutron star, fermionic superfluidity requires pairing of fermions, particles with half-integer spin. For an equal mixture of two states of fermions (&#34;spin up&#34; and &#34;spin down&#34;), pairing can be complete and the entire system will become superfluid. When the two populations of fermions

M. Krawiec, T. Kwapinski

We study transport properties of a strongly correlated monoatomic chain coupled to metallic leads. Our system is described by tight binding Hubbard-like model in the limit of strong on-site electron-electron interactions in the wire. The equation of motion technique in the slave boson representation has been applied to obtain analytical and numerical results

A. Kashuba

In two dimensional electron system in magnetic fields such that the Fermi energy lies in high Landau levels and driven by microwave $ac$-field a divergence of the Coulomb screening due to the Ryzhii photocurrent is predicted. A model of magneto-transport with superposition of long range and short range disorders is introduced. In this model the larger is the

L. Pal

The time process of transport on randomly evolving trees is investigated. By introducing the notions of living and dead nodes a model of random tree evolution is constructed which describes the spreading in time of objects corresponding to nodes. By using the method of the age-dependent branching processes we derive the joint distribution function of the num

Yong-Ping Zhang, Hui Yu, Ying-Fang Gao, J. -Q. Liang

Quantum transport through a double Aharonov-Bohm-interferometer in the presence of Andreev reflection is investigated in terms of the nonequilibrium Green function method with which the reflection current is obtained. Tunable Andreev reflection probabilities depending on the interdot coupling strength and magnetic flux as well are analysised in detail. It is

C. Stari, A. Moreno-Gobbi, A. W. Mombru, S. Sergeenkov

In this work we present the study of the elastic properties of polycrystalline samples of superconducting YBa_2Cu_3O_7 prepared by the sol-gel method. The quality of all samples was checked by x-ray diffraction and scanning electronic microscopy while their physical properties were verified by transport and magnetic measurements. The elastic study was perfor

Yong-Ping Zhang, Ying-Fang Gao, J. -Q. Liang

We investigate the effect of measurement on the persistent current density in a lattice ring penetrated by an Aharonov-Bohm flux and coupled to a quantum dot which is continuously monitored by a point contact detector. It is demonstrated by explicit analysis of the time-evolution of current density that the persistent current in the lattice ring is suppresse

Jaroslav Tobik, Erio Tosatti

We present ab-initio density functional (DFT) calculations of the vibrational spectra of neutral Magnesium phthalocyanine (MgPc) molecule and of its Raman scattering intensities.

J. Takeya, K. Tsukagoshi, Y. Aoyagi, T. Takenobu

Hall effect is detected in organic field-effect transistors, using appropriately shaped rubrene (C42H28) single crystals. It turned out that inverse Hall coefficient, having a positive sign, is close to the amount of electric-field induced charge upon the hole accumulation. The presence of the normal Hall effect means that the electromagnetic character of th

Régis Guégan, Denis Morineau, Claude Loverdo, Wilfried Béziel

We present a neutron scattering analysis of the structure of the smectic liquid crystal octylcyanobiphenyl (8CB) confined in one-dimensional nanopores of porous silicon films (PS). The smectic transition is completely suppressed, leading to the extension of a short-range ordered smectic phase aligned along the pore axis. It evolves reversibly over an extende

A. E. Karakozov, E. G. Maksimov

The restricted optical sum rule and its dependence on the temperature, a superconducting gap and the cutoff energy have been investigated. As known this sum rule depends on the cutoff energy and the relaxation rate even for a homogeneous electron gas interacting with impurities or phonons. It is shown here that additional dependence of the spectral weight on

Ajay Sharma, Subhasis Sarangi, S. V. Bhat

The &#39;two-electron&#39; doped rare earth mangnites Ca_1-x Ce_x MnO_3 (x = 0.1,0.2) are probed using resistivity, ac susceptibility and electron paramagnetic resonance (EPR) measurements across their respective charge ordering (CO) temperatures T_CO = 173 K and 250 K. The EPR &#39;g&#39; factor and intensity as well as the transport and magnetic behaviours

Wang-Chang Su

We present the analytical results at the mean-field level for the asymmetrical fermion system with attractive contact interaction at the zero temperature. The results can be expressed in terms of linear combinations of the elliptic integrals of the first and second kinds. In the limit of small gap parameter, we discuss how the asymmetry in fermion species af

I. Ya. Korenblit, A. Aharony, O. Entin-Wohlman

Using the experimental data given in Phys. Rev. B70, 220507 (2004), we show that -- unlike the effective coupling discussed in this paper -- the net average antiferromagnetic interlayer coupling in doped lanthanum cuprates depends only weakly on the doping or on the temperature. We argue that the effective coupling is proportional to the square of the stagge

A. Oosawa, Y. Nishiwaki, T. Kato, K. Kakurai

Neutron inelastic scattering measurements have been performed in order to investigate the magnetic excitations in the quasi-1D Ising-like antiferromagnet TlCoCl$_3$. We observed the magnetic excitation, which corresponds to the spin-wave excitation continuum corresponding to the domain-wall pair excitation in the 1D Ising-like antiferromagnet. According to t

Neil Bushong, Na Sai, Massimiliano Di Ventra

We show, using a tight-binding model and time-dependent density-functional theory, that a quasi-steady state current can be established dynamically in a finite nanoscale junction without any inelastic effects. This is simply due to the geometrical constriction experienced by the electron wavepackets as they propagate through the junction. We also show that i

T. K. Kopec

The quantum interference effects due to the Aharonov-Bohm-type phase factors are studied in the layered $t-t&#39;-t_\perp-U-J$ strongly correlated system relevant for cuprates. Casting Coulomb interaction in terms of composite-fermions via the flux attachment facility, we argue that U(1) compact group instanton events labeled by a topological winding number

P. Chang, S. Morsink, L. Bildsten, I. Wasserman

The discovery of the first gravitationally redshifted spectral line from a neutron star (NS) by Cottam, Paerels and Mendez has triggered theoretical studies of the physics of atomic line formation in NS atmospheres. Chang, Bildsten and Wasserman showed that the hydrogenic Fe H$α$ line formed above the photosphere of a bursting NS is intrinsically broad. We n

P. Kalas

Near-infrared imaging with the Hubble Space Telescope recently revealed a circumstellar dust disk around the A star HD 32297. Dust scattered light is detected as far as 400 AU radius and the linear morphology is consistent with a disk ~10 degrees away from an edge-on orientation. Here we present the first optical images that show the dust scattered light mor