October 2006 arXiv papers — page 24

Jerome Beugnon, Matthew Jones, Jos Dingjan, Benoit Darquié

When two indistinguishable single photons are fed into the two input ports of a beam splitter, the photons will coalesce and leave together from the same output port. This is a quantum interference effect, which occurs because the two possible paths where the photons leave in different output ports interfere destructively. This effect was first observed in p

Yong Zhang

We explore algebraic and topological structures underlying the quantum teleportation phenomena by applying the braid group and Temperley--Lieb algebra. We realize the braid teleportation configuration, teleportation swapping and virtual braid representation in the standard description of the teleportation. We devise diagrammatic rules for quantum circuits in

John Conway, Simon Kochen

We respond to Stephen Adler's comments on our paper "The Free Will Theorem",and add some further observations.

Koenraad M. R. Audenaert

We derive an inequality relating the entropy difference between two quantum states to their trace norm distance, sharpening a well-known inequality due to M. Fannes. In our inequality, equality can be attained for every prescribed value of the trace norm distance.

Qiang Zhang, Xiao-Hui Bao, Chao-Yang Lu, Xiao-Qi Zhou

We present a feasible and efficient scheme, and its proof-of-principle demonstration, of creating entangled photon pairs in an event-ready way using only simple linear optical elements and single photons. The quality of entangled photon pair produced in our experiment is confirmed by a strict violation of Bell's inequality. This scheme and the associated

F. G. Masclaux, J. -P. Galaud, R. Pont-Lezica

Proteins synthesized on membrane-bound ribosomes are sorted at the Golgi apparatus level for delivery to various cellular destinations: the plasma membrane or the extracellular space, and the lytic vacuole or lysosome. Sorting involves the assembly of vesicles, which preferentially package soluble proteins with a common destination. The selection of proteins

Malik Hocine, Nicolas Fressengeas, Godefroy Kugel, Christiane Carré

Manufacturing end-of-fiber optical components able to realize optical functions ranging from a simple lens to more complex functions such as mode selective components is a decisive but \emph{a priori} complex task owing to the fiber core dimensions. Effective low cost methods allowing to grow polymer components by free-radical photopolymerization using the l

B. S. Alexandrov, K. O. Rasmussen, A. T. Findikoglu, A. R. Bishop

We analyze the propagation of electromagnetic waves in media where the dielectric constants undergo rapid temporal periodic modulation. Both spatially homogeneous and periodic media are studied. Fast periodic temporal modulation of the dielectric constant of a homogeneous medium leads to existence of photonic band-gap like phenomena. In the presence of both

J. Eggers, M. A. Fontelos, D. Leppinen, J. H. Snoeijer

We investigate the collapse of an axisymmetric cavity or bubble inside a fluid of small viscosity, like water. Any effects of the gas inside the cavity as well as of the fluid viscosity are neglected. Using a slender-body description, we show that the minimum radius of the cavity scales like $h_0 \propto t'^α$, where $t'$ is the time from collapse. T

Wen-Jie Bai, Tao Zhou, Bing-Hong Wang

In this paper, we investigate two major immunization strategies, random immunization and targeted immunization, of the susceptible-infected (SI) Model on the Barabási-Albert (BA) networks. For the heterogenous structure, the random strategy is quite ineffective if the vaccinated proportion is quite small, while the targeted one which prefers to vaccinate the

V. A. Panchelyuga, V. A. Kolombet, M. S. Panchelyuga, S. E. Shnoll

The paper presents an investigation of local-time effect - one of the manifestations of macroscopic fluctuations phenomena. Was shown the existence of the named effect for longitudinal distance between locations of measurements up to 500 meters. Also a structure of intervals distribution in neighborhood of local-time peak was studied and splitting of the pea

Reza Dastvan

Based on superfluid behavior of a (boson) dark matter as the light itself, a unified model for dark matter and quintessence is proposed. Inspired by (O'Dell et al. 2000) which in an exciting study showed that particular configurations of intense off-resonant laser beams (simulate the Bose-Einstein condensate) can give rise to an attractive 1/r interatomi

Branislav Brutovsky, Denis Horvath, Vladimir Lisy

The inverse geometric approach to the modeling of the growth of circular objects revealing required features, such as the velocity of the growth and fractal behavior of their contours, is presented. It enables to reproduce some of the recent findings in morphometry of tumors with the possible implications for cancer research. The technique is based on cellul

D. Krauss-Varban

In many plasmas, in particular in space science, protons govern much of the essential physics. Minority ions, suprathermal tails, and electrons at times account for additional details. However, electron effects usually appear on much smaller spatial and temporal scales. For more than two decades, scientists have refined computational models that concentrate

G. Hagen, D. J. Dean, M. Hjorth-Jensen, T. Papenbrock

We develop ab-initio coupled-cluster theory to describe resonant and weakly bound states along the neutron drip line. We compute the ground states of the helium chain 3-10He within coupled-cluster theory in singles and doubles (CCSD) approximation. We employ a spherical Gamow-Hartree-Fock basis generated from the low-momentum N3LO nucleon-nucleon interaction

L. Platter

The effective field theory with contact interactions alone is a powerful tool to compute low-energy observables for three-body systems with large scattering length. Recent calculations including effective range corrections are discussed and results are presented.

Jeremy W. Holt, G. E. Brown, Jason D. Holt, T. T. S. Kuo

We present a description of symmetric nuclear matter within the framework of Landau Fermi liquid theory. The low momentum nucleon-nucleon interaction V(low-k) is used to calculate the effective interaction between quasiparticles on the Fermi surface, from which we extract the quasiparticle effective mass, the nuclear compression modulus, the symmetry energy,

L. P. Kaptari, B. Kampfer

Dalitz decays of $ω$ and $ρ$ mesons, $ω\to π^0γ^*\toπ^0 e^+e^-$ and $ρ^0\to π^0γ^*\toπ^0 e^+e^-$, produced in $pp$ collisions are calculated within a covariant effective meson-nucleon theory. We argue that the $ω$ transition form factor $F_{ω\to π^0γ^*}$ is experimentally accessible in a fairly model independent way in the reaction $pp \to pp π^0 e^+ e^-$ fo

FOPI Collaboration, W. Reisdorf

Using the large acceptance apparatus FOPI, we study pion emission in the reactions (energies in GeV/nucleon are given in parentheses): 40Ca+40Ca (0.4, 0.6, 0.8, 1.0, 1.5, 1.93), 96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0, 1.5), 197Au+197Au (0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The observables include longitudinal and transverse rapidity distributions and stopp

Y. Matsuno, V. S. Shchesnovich, A. M. Kamchatnov, R. A. Kraenkel

The Whitham modulation equations for the parameters of a periodic solution are derived using the generalized Lagrangian approach for the case of damped Benjamin-Ono equation. The structure of the dispersive shock in internal wave in deep water is considered by this method.

Robert D. Edwards

This article is one of three highly influential articles on the topology of manifolds written by Robert D. Edwards in the 1970's but never published. It presents the initial solutions of the fabled Double Suspension Conjecture. (The other two articles are: 'Approximating certain cell-like maps by homeomorphisms' and 'Topological regular neigh

Junho Lee, Thomas H. Parker

We prove a structure theorem for the Gromov-Witten invariants of compact Kahler surfaces with geometric genus $p_g>0$. Under the technical assumption that there is a canonical divisor that is a disjoint union of smooth components, the theorem shows that the GW invariants are universal functions determined by the genus of this canonical divisor components and

Nils Ovrelid, Sophia Vassiliadou

Let X be an irreducible n-dimensional projective variety in CP^N with arbitrary singular locus. We prove that the L2-(p,1)-d-bar cohomology groups (with respect to the Fubini-Study metric) of the regular part of X are finite dimensional.

Arkady Berenstein, David Kazhdan

This is an exposition of the results on Geometric crystals and the associated Kashiwara crystal bases (presented by the first author in RIMS, August 2004)

William W. Menasco

In Theorem 1.2 of the paper math.GT/0002110 the author claimed to have proved that all transversal knots whose topological knot type is that of an iterated torus knot (we call them cable knots) are transversally simple. That theorem is false, and the Erratum math.GT/0610565 identifies the gap. The purpose of this paper is to explore the situation more deeply

William W. Menasco

In math.GT/0002110 the author's Theorems 1.1 and 1.2, combined, implied that iterated torus knots are transversally simple. This result is in error and this erratum pin points the error. In "An addendum on iterated torus knots" a more subtle result is proven resulting in giving a geometric realization of the Honda-Etnyre transverse (2,3)-cable of

Joseph Najnudel

In this paper, we construct a family of probability measures, by penalizations of a Walsh Brownian motion with a weight dependent on its value and its local time at a time t. We prove that this family converges to a probability measure as t tends to infinity, and we study the behaviour of this limit measure.

Jordi Lopez Abad, Stevo Todorcevic

We present a Banach space $\mathfrak X$ with a Schauder basis of length $ω\_1$ which is saturated by copies of $c\_0$ and such that for every closed decomposition of a closed subspace $X=X\_0\oplus X\_1$, either $X\_0$ or $X\_1$ has to be separable. This can be considered as the non-separable counterpart of the notion of hereditarily indecomposable space. In

Marie Cottrell, Barbara Hammer, Alexander Hasenfuss, Thomas Villmann

Neural Gas (NG) constitutes a very robust clustering algorithm given euclidian data which does not suffer from the problem of local minima like simple vector quantization, or topological restrictions like the self-organizing map. Based on the cost function of NG, we introduce a batch variant of NG which shows much faster convergence and which can be interpre

Nicolas Bouleau

The aim of this study is to clarify the consequences of recent theoretical results for the numerical computation of expectation by the shift method, and in particular to yield sufficient criteria for the existence of speed of convergence of the type `iterated logarithm' in several situations. We deepen the case of the Wiener space because it contains man

Mario Bessa, Jorge Rocha

Baraviera and Bonatti proved that it is possible to perturb, in the c^1 topology, a volume-preserving and partial hyperbolic diffeomorphism in order to obtain a non-zero sum of all the Lyapunov exponents in the central direction. In this article we obtain the analogous result for volume-preserving flows.

Ana Breda, Antonio Breda d'Azevedo, Domenico Catalano

By a covering of a group G we mean an epimorphism from a group F to G. Introducing the notion of strong covering as a covering pi:F-->G such that every automorphism of G is a projection via pi of an automorphism of F, the main aim of this paper is to characterise double coverings which are strong. This is done in details for metacyclic groups, rotary platoni

Walter Becker, Elaine W. Becker

The automorphism groups for the groups of orders $8p$ and $8p^2$ are given. The calculations were done using the programming language CAYLEY. Explicit presentations for both the groups of these orders and their automorphism groups are given.

I. D. Shkredov

Let $A$ be a subset of $\mathbb{Z} / N\mathbb{Z}$ and let $\mathcal{R}$ be the set of large Fourier coefficients of $A$. Properties of $\mathcal{R}$ have been studied in works of M.-- C. Chang, B. Green and the author. In the paper we obtain some new results on sets of large exponential sums.

Noga Alon, Itai Benjamini, Eyal Lubetzky, Sasha Sodin

We compute the mixing rate of a non-backtracking random walk on a regular expander. Using some properties of Chebyshev polynomials of the second kind, we show that this rate may be up to twice as fast as the mixing rate of the simple random walk. The closer the expander is to a Ramanujan graph, the higher the ratio between the above two mixing rates is. As a

Johann Cigler

We give generalizations of a finite version of Euler's pentagonal number theorem and of a q-identity of Gauss.

L. A. Gutnik

The work studies some Difference equations, which are connected with Mejer's function.

L. A. Alexeyeva

The multivariate analogue of Dalamber's equation in the space of generalized functions is considered. The method of generalized functions for the building of solutions of nonstationary boundary value problems for wave equations in spaces of different dimensions is elaborated. Dynamic analogues of Green and Gauss formulas for solutions of wave equation in

Rafael Lopez

A linear Weingarten surface in Euclidean space ${\bf R}^3$ is a surface whose mean curvature $H$ and Gaussian curvature $K$ satisfy a relation of the form $aH+bK=c$, where $a,b,c\in {\bf R}$. Such a surface is said to be hyperbolic when $a^2+4bc<0$. In this paper we classify all rotational linear Weingarten surfaces of hyperbolic type. As a consequence, we o

Rui Loja Fernandes

We describe a symplectization functor from the Poisson category to the symplectic &#34;category&#34; and we study some of its properties.

Thanos Gentimis

It is proven that if a finitely presented group is one ended it has asymptotic dimension bigger than one. It follows that finitely presented groups with asdim 1 are virtually free. A counterexample is given for the finitely generated case.

Izzet Coskun, Ravi Vakil

We describe recent work on positive descriptions of the structure constants of the cohomology of homogeneous spaces such as the Grassmannian, by degenerations and related methods. We give various extensions of these rules, some new and conjectural, to K-theory, equivariant cohomology, equivariant K-theory, and quantum cohomology.

X. W. C. Faber

A two-dimensional Besicovitch set over a finite field is a subset of the finite plane containing a line in each direction. In this paper, we conjecture a sharp lower bound for the size of such a subset and prove some results toward this conjecture.

Thomas M. Fiore

In this paper I develop categorical foundations needed for a rigorous approach to the definition of conformal field theory outlined by Graeme Segal. I discuss pseudo algebras over theories and 2-theories, their pseudo morphisms, bilimits, bicolimits, biadjoints, stacks, and related concepts.

Hao Wu

We establish a relation between several easy-to-calculate numerical invariants of generic knots in $\mathbb{H}^2 \times S^1$, and use it to give a new method of computing the Thurston-Bennequin number of Legendrian knots in the tight contact $\mathbb{R}^3$.

Nicolas Boulanger, Fabien Buisseret, Philippe Spindel

We investigate the quantum motion of a neutral Dirac particle bouncing on a mirror in curved spacetime. We consider different geometries: Rindler, Kasner-Taub and Schwarzschild, and show how to solve the Dirac equation by using geometrical methods. We discuss, in a first-quantized framework, the implementation of appropriate boundary conditions. This leads u

Patrick Peter, E. J. C. Pinho, Nelson Pinto-Neto

We show that a contracting universe which bounces due to quantum cosmological effects and connects to the hot big-bang expansion phase, can produce an almost scale invariant spectrum of perturbations provided the perturbations are produced during an almost matter dominated era in the contraction phase. This is achieved using Bohmian solutions of the canonica

Alfredo Herrera-Aguilar, Hugo Raymundo Marquez-Falcon

We show how to obtain a non-supersymmetric black ring configuration in the framework of 5D Heterotic String Theory using the matrix Ernst potential (MEP) formalism, which enables us to include non-trivial dilaton, gauge and antisymmetric tensor fields.

Charles B. Thorn

I describe Field/String duality as applied to the response of gauge fields to separated quark and antiquark sources. This is a talk contributed to the conference Quark Confinement and the Hadron Spectrum VII, Ponta Delgada, Azores, 2-7 September 2006.

Xu Mingmei, Liu Lianshou

Different methods to reconstruct the quark-gluon fusion product and current jet are tried in deep-inelastic e-p scattering events with instanton as background generated by QCDINS Monte Carlo code. A comparison of these methods are performed and a good method is found which can reconstruct well the energies of current jet and instanton product as well as the

Rouzbeh Allahverdi, Asko Jokinen, Anupam Mazumdar

Minimal Supersymmetric Standard Model with gauge mediated supersymmetry breaking has all the necessary ingredients for a successful sub-eV Hubble scale inflation $H_{\rm inf} \sim 10^{-3}-10^{-1}$ eV. The model generates the right amplitude for scalar density perturbations and a spectral tilt within the range, $0.90 \leq n_s \leq 1$. The reheat temperature i

Yazid Delenda, Robert Appleby, Andrea Banfi, Mrinal Dasgupta

We revisit the impact of the jet algorithm on predictions of energy flow into gaps between hard jets, defined using the kt clustering procedure. The resulting prediction has two distinct components: a primary emission piece that is related to independent emission of soft gluons by the hard jets and a correlated emission (non-global) piece known only in the l

D. Ebert, R. N. Faustov, V. O. Galkin

Semileptonic decays of heavy baryons consisting of one heavy (Q=b,c) and two light (q=u,d,s) quarks are considered in the heavy-quark--light-diquark approximation. The relativistic quasipotential equation is used for obtaining masses and wave functions of both diquarks and baryons within the constituent quark model. The weak transition matrix elements are ex

Boris Krippa

The application of the exact renormalisation group to symmetric as well as asymmetric many-fermion systems with a short-range attractive force is studied. Assuming an ansatz for the effective action with effective bosons, describing pairing effects a set of approximate flow equations for the effective coupling including boson and fermionic fluctuations has b

Stanley J. Brodsky, Feng Yuan

The large-$x$ behavior of the transverse-momentum dependent quark distributions is analyzed in the factorization-inspired perturbative QCD framework, particularly for the naive time-reversal-odd quark Sivers function which is responsible for the single transverse-spin asymmetries in various semi-inclusive hard processes. By examining the dominant hard gluon

A. Bartl, E. Christova, K. Hohenwarter-Sodek, T. Kernreiter

We propose CP asymmetries based on triple product correlations in the decays sbottom_m -> top chargino_j with subsequent decays of top and chargino_j. For the subsequent chargino_j decay into a leptonic final state l^- νneutralino_1 we consider the three possible decay chains chargino_j -> l^- sneutrino -> l^- νneutralino_1, chargino_j -> slepton_n ν-> l^- ν

Dan Pirjol, Carlos Schat

We briefly discuss the large Nc picture for excited baryons, present a new method for the calculation of matrix elements and illustrate it by computing the strong decays of heavy exotic states.

B. F. L. Ward

We present the current status of the a new approach to quantum general relativity based on the exact resummation of its perturbative series as that series was formulated by Feynman. We show that the resummed theory is UV finite and we present some phenomenological applications as well.

B. F. L Ward, S. A. Yost

We discuss the elements of QED X QCD exponentiation and its interplay with shower/ME matching and IR-improved DGLAP theory in precision LHC physics scenarios. Applications to single heavy gauge boson production at hadron colliders are illustrated.

B. El-Bennich, O. M. A. Leitner, B. Loiseau, J. -P. Dedonder

Decay amplitudes of D(D_s)->f0(980)X, X=pi, K, are compared to experimental branching ratios with the aim of singling out the poorly known D->f0(980) transition form factor in these amplitudes. Since the other elements of the amplitudes are either calculable in an effective QCD theory using operator product expansion or are known from experiment (e.g. the pi

Wolfgang Lucha, Dmitri Melikhov, Silvano Simula

We show that, in a model based exclusively on constituent-quark degrees of freedom interacting via a potential, the full axial current is conserved if the spectrum of \bar QQ states contains a massless pseudoscalar. The current conservation emerges nonperturbatively if the model satisfies certain constraints on (i) the axial coupling g_A of the constituent q

Chen Gang, Yu Meiling, Liu Lianshou

The production scale and internal structure of jets produced in high energy collisions are studied using Jetset7.4 and Herwig5.9 Monte Carlo generators. Two scales are found. One is the jet-development scale, which determines the size of the jet developed from a mother-parton. The other one is the jet-production scale, the jets produced with this scale are t

C. Albertus, J. M. Flynn, E. Hernandez, J. Nieves

The semileptonic decay B->pi is studied starting from a simple quark model and taking into account the effect of the B* resonance. A novel, multiply subtracted, Omnès dispersion relation has been implemented to extend the predictions of the quark model to all physical q^2 values. We find |V_{ub}|=0.0034 +/- 0.0003(exp.)+/- 0.0007(theory), in good agreement w

Min Li

We present preliminary results for the static quark potential computed on some of the DWF lattice configurations generated by the RBC-UKQCD collaborations. Most of these results were obtained using Wilson lines joining spatial planes fixed into the Coulomb gauge. We compare the results from this method with the earlier ones on $16^3 \times 32$ lattices using

Adriano Di Giacomo

The status of the theory of color confinemnt is discussed.

Adriano Di Giacomo

The monopole order parameter of QCD is computed in terms of gauge invariant field strength correlators. Both quantities are partially known from numerical simulations on the lattice. A new insight results on the structure of the confining vacuum.

Adriano Di Giacomo

The order parameter for monopole condensation is computed in terms of gauge invariant field strength correlators. Important properties emerge of the correlators in the confined phase, which could not be extracted by existing numerical determinations on the lattice.

Adriano Di Giacomo

The disorder parameter $<μ>$ for the condensation of monopoles in QCD is estimated analytically in terms of gauge invariant field strength correlators. The continuum limit is discussed.

Sinya Aoki, Oliver Bär

We present a condition for automatic O$(a)$ improvement in twisted mass lattice QCD, using symmetries of the Symanzik effective theory. If the continuum part of the Symanzik effective theory is invariant under a particular transformation, named $T_1$ in this report, scaling violations of all quantities invariant under $T_1$ transformation are even in the lat

Robert V. Kowalewski

The current status of the determinations of the CKM elements Vub and Vcb is reviewed and future prospects are discussed.

The OPAL collaboration

This paper describes a topological search for an invisibly decaying Higgs boson,H, produced via the Bjorken process (e+e- -> HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to 209 GeV corresponding to a total integrated luminosity of 629pb-1. In the analysis only hadronic decays of the Z boson ar

E. N. Glass

A method for mapping known cylindrical magnetovac solutions to solutions in torus coordinates is developed. Identification of the cylinder ends changes topology from R1 x S1 to S1 x S1. An analytic Einstein-Maxwell solution for a toroidal magnetic field in tori is presented. The toroidal interior is matched to an asymptotically flat vacuum exterior, connecte

Jacek Jezierski, Maciej Łukasik

Symmetric conformal Killing tensors and (skew-symmetric) conformal Yano-Killing tensors for Euclidean Taub-NUT metric are given in explicit form. Relations between Yano and CYK tensors in terms of conformal rescaling are discussed.

Andrew P. Lundgren, Bjoern S. Schmekel, James W. York

Pointlike objects cause many of the divergences that afflict physical theories. For instance, the gravitational binding energy of a point particle in Newtonian mechanics is infinite. In general relativity, the analog of a point particle is a black hole and the notion of binding energy must be replaced by quasilocal energy. The quasilocal energy (QLE) derived

Shengtian Yang, Peiliang Qiu

A general lossless joint source-channel coding scheme based on linear codes is proposed and then analyzed in this paper. It is shown that a linear code with good joint spectrum can be used to establish limit-approaching joint source-channel coding schemes for arbitrary sources and channels, where the joint spectrum of the code is a generalization of the inpu

Mohamed El Baker Nassar, Radu State, Olivier Festor

VoIP applications are emerging today as an important component in business and communication industry. In this paper, we address the intrusion detection and prevention in VoIP networks and describe how a conceptual solution based on the Bayes inference approach can be used to reinforce the existent security mechanisms. Our approach is based on network monito

Jinhua Jiang, Yan Xin, Hari Krishna Garg

In this paper, we consider the discrete memoryless interference channel with common information, in which two senders need deliver not only private messages but also certain common messages to their corresponding receivers. We derive an achievable rate region for such a channel by exploiting a random coding strategy, namely cascaded superposition coding. We

Praveen Kumar Gopala, Young-Han Nam, Hesham El Gamal

We consider communication over Automatic Repeat reQuest (ARQ) memoryless channels with deadlines. In particular, an upper bound L is imposed on the maximum number of ARQ transmission rounds. In this setup, it is shown that incremental redundancy ARQ outperforms Forney&#39;s memoryless decoding in terms of the achievable error exponents.

Jun Hayakawa, Shoji Ikeda, Young Min Lee, Fumihiro Matsukura

We report tunnel magnetoresistance (TMR) ratios as high as 472% at room temperature and 804% at 5 K in pseudo-spin valve (SV) CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) annealed at 450oC, which is approaching the theoretically predicted value. By contrast, the TMR ratios for exchange-biased (EB) SV MTJs with a MnIr antiferromagnetic layer are found to

Pierre Le Doussal, Kay Joerg Wiese

We show how the renormalized force correlator Delta(u), the function computed in the functional RG (FRG) field theory, can be measured directly in numerics and experiments on the dynamics of elastic manifolds in presence of pinning disorder. For equilibrium dynamics we recover the relation obtained recently in the statics between Delta(u) and a physical obse

Kai-Mei C. Fu, Wenzheng Yeo, Susan Clark, Charles Santori

We observe millisecond spin-flip relaxation times of donor-bound electrons in high-purity n-GaAs . This is three orders of magnitude larger than previously reported lifetimes in n-GaAs . Spin-flip times are measured as a function of magnetic field and exhibit a strong power-law dependence for fields greater than 4 T . This result is in qualitative agreement

Qingshan Yuan, Xin-Zhong Yan, C. S. Ting

An intrinsic physical mechanism, based on the doping evolution of the Fermi surface (FS), is explored to reconcile the contradictory experimental results on the superconducting (SC) pairing symmetry in electron-doped cuprates. It is argued that the FS pocket around $(π/2,π/2)$ has not yet formed until doping reaches about the optimal value. Therefore, in the

M. Martinez-Mares, G. Akguc, R. A. Mendez-Sanchez

We show that the distribution of the conductance in quasi-one-dimensional systems with surface disorder is correctly described by the Dorokhov-Mello-Pereyra-Kumar equation if one includes direct processes in the scattering matrix S through Poisson&#39;s kernel. Although our formulation is valid for any arbitrary number of channels, we present explicit calcul

B. Bourlon, C. Miko, L. Forro, D. C. Glattli

We present local and non-local electron transport measurements on individual multi-wall nanotubes for bias voltage between 0 and about 4 V. Local current-voltage characteristics are quite linear. In contrast, non-local measurements are highly non-linear; the differential non-local conductance can even become negative in the high-bias regime. We discuss the r

Claudia Mondelli, Miguel A. González, Francesco Albergamo, Carlos Carbajo

We present a comparative study of the excitations in bulk and liquid D2 confined within the pores of MCM-41. The material (Mobile Crystalline Material-41) is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous SiO2.

Miguel A. Amat, Ioannis G. Kevrekidis, Dimitrios Maroudas

We present a coarse molecular-dynamics (CMD) approach for the study of stress-induced structural transformations in crystals at finite temperatures. The method relies on proper choice of a coarse variable (order parameter, observable), which parameterizes the changes in effective free energy during the transformation. Results are reported for bcc-to-hcp latt

Ania C. Bleszynski, Floris A. Zwanenburg, Robert M. Westervelt, Aaroud L. Roest

We show how a scanning probe microscope (SPM) can be used to image electron flow through InAs nanowires, elucidating the physics of nanowire devices on a local scale. A charged SPM tip is used as a movable gate. Images of nanowire conductance vs. tip position spatially map the conductance of InAs nanowires at liquid He temperatures. Plots of conductance vs.

Kang Chen, Yu-qiang Ma

We investigate the interaction energy between two colloidal particles on or immersed in nonadsorbing polymer brushes grafted onto the substrate as a function of the separation of the particles by use of self-consistent field theory calculation. Depending on the colloidal size and the penetration depth, we demonstrate an existence of repulsive energy barrier

D. Dagnino, N. Barberán, M. Lewenstein, K. Osterloh

We study the signatures of rotational and phase symmetry breaking in small rotating clouds of trapped ultracold Bose atoms by looking at rigorously defined condensate wave function. Rotational symmetry breaking occurs in narrow frequency windows, where the ground state of the system has degenerated with respect to the total angular momentum, and it leads to

T. G. Mattos, J. G. Moreira, A. P. F. Atman

We introduce a new method based on cellular automata dynamics to study stochastic growth equations. The method defines an interface growth process which depends on height differences between neighbors. The growth rule assigns a probability $p_{i}(t)=ρ$ exp$[κΓ_{i}(t)]$ for a site $i$ to receive one particle at a time $t$ and all the sites are updated simulta

J. Szavits-Nossan, K. Uzelac

Generalization of the one-dimensional totally asymmetric exclusion process (TASEP) with open boundary conditions in which particles are allowed to jump $l$ sites ahead with the probability $p_l\sim 1/l^{σ+1}$ is studied by Monte Carlo simulations and the domain-wall approach. For $σ>1$ the standard TASEP phase diagram is recovered, but the density profiles n

A. R. Akhmerov, C. W. J. Beenakker

A ballistic strip of graphene (width W>> length L) connecting two normal metal contacts is known to have a minimum conductivity of 4e^{2}/pi h at the Dirac point of charge neutrality. We calculate what happens if one of the two contacts becomes superconducting. While the ballistic conductance away from the Dirac point is increased by Andreev reflection at th

Juha Karvanen, Juha J. Vartiainen, Andrey Timofeev, Jukka Pekola

We study the optimal design of switching measurements of small Josephson junction circuits which operate in the macroscopic quantum tunnelling regime. Starting from the D-optimality criterion we derive the optimal design for the estimation of the unknown parameters of the underlying Gumbel type distribution. As a practical method for the measurements, we pro

A. V. Syromyatnikov, S. V. Maleyev

Dynamical properties of an impurity spin coupled symmetrically to sublattices of ordered 2D Heisenberg quantum antiferromagnet (i.e., frustrated impurity spin) are discussed at $T\ge0$ (existence of a small interaction stabilizing the long range order at $T\ne0$ is implied). We continue our study on this subject started in Phys.Rev.B 72, 174419 (2005), where

Silvio R. Dahmen, L. Sittler, H. Hinrichsen

We study a contact process on a two-dimensional square lattice which is diluted by randomly removing bonds with probability p. For p<1/2 and varying birth rate $λ$ the model was shown to exhibit a continuous phase transition which belongs to the universality class of strongly disordered directed percolation. The phase transition line terminates in a multicri

F. Koermann, S. Schwieger, J. Kienert, W. Nolting

We present a new type of temperature driven spin reorientation transition (SRT) in thin films. It can occur when the lattice and the shape anisotropy favor different easy directions of the magnetization. Due to different temperature dependencies of the two contributions the effective anisotropy may change its sign and thus the direction of the magnetization

S. Glocke, A. Klümper, H. Rakoto, J. M. Broto

We consider the spin-1/2 antiferromagnetic Heisenberg chain in a staggered magnetic field describing materials such as copper benzoate and copper pyrimidine dinitrate. Using the density-matrix renormalization group for transfer matrices (TMRG) we calculate the magnetization of these materials at finite temperature and arbitrary magnetic field. These results

Takashi Hotta

We discuss low-temperature multipole states of Nd-based filled skutterudites by analyzing a multiorbital Anderson model with the use of a numerical renormalization group method. In order to determine the multipole state, we take a procedure to maximize the multipole susceptibility matrix. Then, it is found that the dominant multipole state is characterized b

Ö. Legeza, J. Sólyom, L. Tincani, R. M. Noack

We propose a new approach to study quantum phase transitions in low-dimensional fermionic or spin models that go from uniform to spatially inhomogeneous phases such as dimerized, trimerized, or incommensurate phases. It is based on studying the length dependence of the von Neumann entropy and its corresponding Fourier spectrum for finite segments in the grou

M. Fattori, T. Koch, S. Goetz, A. Griesmaier

We demonstrate demagnetization cooling of a gas of ultracold $^{52}$Cr atoms. Demagnetization is driven by inelastic dipolar collisions which couple the motional degrees of freedom to the spin degree. By that kinetic energy is converted into magnetic work with a consequent temperature reduction of the gas. Optical pumping is used to magnetize the system and