July 2003 arXiv papers — page 7

P. E. Jönsson, R. Mathieu, P. Nordblad, H. Yoshino

Extensive experimental and numerical studies of the non-equilibrium dynamics of spin glasses subjected to temperature or bond perturbations have been performed to investigate chaos and memory effects in selected spin glass systems. Temperature shift and cycling experiments were performed on the strongly anisotropic Ising-like system {\ising} and the weakly a

Hajime Takayama, Koji Hukushima

Spin-glass (SG) states of the 3-dimensional Ising Edwards-Anderson model under a static magnetic field $h$ are examined by means of the standard Monte Carlo simulation on the field-shift aging protocol at temperature $T$. For each process with $(T; \tw, h)$, $\tw$ being the waiting time before the field is switched on, we extract the dynamical crossover time

E. L. Bratkovskaya, S. Soff, H. Stoecker, M. van Leeuwen

We investigate transverse hadron spectra from relativistic nucleus-nucleus collisions which reflect important aspects of the dynamics - such as the generation of pressure - in the hot and dense zone formed in the early phase of the reaction. Our analysis is performed within two independent transport approaches (HSD and UrQMD) that are based on quark, diquark

H. Fehrmann, M. A. Baranov, B. Damski, M. Lewenstein

We determine the phase diagram of a mixture of ultracold bosons and polarized fermions placed in an optical lattice using mean field theory. In the limit of strong atom-atom interactions, there exist quantum phases that involve pairing of fermions with one or more bosons, or bosonic holes, respectively. We obtain the analytic form of the phase boundaries sep

I. Vidana, A. Ramos, A. Polls

The $ΛΛ$ bond energy $ΔB_{ΛΛ}$ in $ΛΛ$ hypernuclei is obtained from a $G$-matrix calculation which includes the coupling between the $ΛΛ$, $ΞN$ and $ΣΣ$ channels, as well as the effect of Pauli blocking to all orders. The Nijmegen NSC97e model is used as bare baryon-baryon interaction in the strangeness $S=-2$ sector. The $ΛΛ$-$ΞN$ coupling increases substan

Abha Dev, Deepak Jain, Shobhit Mahajan

The present day observations favour a universe which is flat, accelerated and composed of $\sim 1/3$ matter (baryonic + dark) and $\sim 2/3$ of a negative pressure component, usually referred to as dark energy or quintessence. The Cosmic Lens All Sky Survey (CLASS), the largest radio-selected galactic mass scale gravitational lens search project to date, has

Włodzimierz Bryc, Amir Dembo, Tiefeng Jiang

We study the limiting spectral measure of large symmetric random matrices of linear algebraic structure. For Hankel and Toeplitz matrices generated by i.i.d. random variables $\{X_k\}$ of unit variance, and for symmetric Markov matrices generated by i.i.d. random variables $\{X_{ij}\}_{j>i}$ of zero mean and unit variance, scaling the eigenvalues by $\sqrt{n

S. Arunagiri, C. Q. Geng

We study Lambda_b --> Lambda pi pi. The branching fraction is predicted to be about 4.38 x 10^{-6}%. Within the standard model, we compute T-odd triple product asymmetries to be about 1.4, 4.3, 6.5 and 7.2% respectively due to s_{Lambda_b}(s_Lambda) . (p_Lambda x p_pi) and p_Lambda (p_pi) . (s_Lambda x s_{Lambda_b}).

Andrew M. Childs, Henry L. Haselgrove, Michael A. Nielsen

We give a simple proof of a formula for the minimal time required to simulate a two-qubit unitary operation using a fixed two-qubit Hamiltonian together with fast local unitaries. We also note that a related lower bound holds for arbitrary n-qubit gates.

Alessandra Gatti, Enrico Brambilla, Morten Bache, Luigi Lugiato

We analytically show that it is possible to perform coherent imaging by using the classical correlation of two beams obtained by splitting incoherent thermal radiation. The case of such two classically correlated beams is treated in parallel with the configuration based on two entangled beams produced by parametric down-conversion, and a basic analogy is poi

Alexia Auffeves, Paolo Maioli, Tristan Meunier, Sebastien Gleyzes

We observe that a mesoscopic field made of several tens of microwave photons exhibits quantum features when interacting with a single Rydberg atom in a high-Q cavity. The field is split into two components whose phases differ by an angle inversely proportional to the square root of the average photon number. The field and the atomic dipole are phase-entangle

S. Hensler, J. Werner, A. Griesmaier, P. O. Schmidt

We have investigated both theoretically and experimentally dipolar relaxation in a gas of magnetically trapped chromium atoms. We have found that the large magnetic moment of 6 $μ_B$ results in an event rate coefficient for dipolar relaxation processes of up to $3.2\cdot10^{-11}$ cm$^{3}$s$^{-1}$ at a magnetic field of 44 G. We present a theoretical model ba

K. R. Parthasarathy

Let ${\cal H}_1,$ ${\cal H}_2$ be finite dimensional complex Hilbert spaces describing the states of two finite level quantum systems. Suppose $ρ_i$ is a state in ${\cal H}_i, i=1,2.$ Let ${\cal C} (ρ_1, ρ_2)$ be the convex set of all states $ρ$ in ${\cal H} = {\cal H}_1 \otimes {\cal H}_2$ whose marginal states in ${\cal H}_1$ and ${\cal H}_2$ are $ρ_1$ and

M. J. Everitt, T. D. Clark, P. B. Stiffell, H. Prance

We present solutions of the time dependent Schrodinger equation for a SQUID ring coupled to an electromagnetic field, both treated quantum mechanically. We that show the SQUID ring can be used to create a maximally entangled state with the em field that without dissipation remains constant in time. Using methods familiar in quantum optics, we extend the mode

W. Dür, H. -J. Briegel

We investigate the lifetime of macroscopic entanglement under the influence of decoherence. For GHZ-type superposition states we find that the lifetime decreases with the size of the system (i.e. the number of independent degrees of freedom) and the effective number of subsystems that remain entangled decreases with time. For a class of other states (e.g. cl

H. Nikolic

The relativistic effects of the integer-spin quantum field theory imply that the wave functions describing a fixed number of particles do not admit the usual probabilistic interpretation. Among several most popular interpretations of quantum mechanics applied to first quantization, the only interpretation for which this fact does not lead to a serious proble

M. Cemal Yalabik

Utilization of a quantum system whose time-development is described by the nonlinear Schrodinger equation in the transformation of qubits would make it possible to construct quantum algorithms which would be useful in a large class of problems. An example of such a system for implementing the logical NOR operation is demonstrated.

Chui-Ping Yang, Shih-I Chu, Siyuan Han

A novel scheme is proposed for realizing quantum entanglement, quantum information transfer and a set of universal quantum gates with superconducting-quantum-interference-device (SQUID) qubits in cavity QED. In the scheme, the two logical states of a qubit are the two lowest levels of the SQUID. An intermediate level of the SQUID is utilized to facilitate co

P. Aniello, V. Man'ko, G. Marmo, A. Porzio

The Hamiltonian describing a single ion placed in a potential trap in interaction with a laser beam is studied by means of a suitable perturbative approach. It is shown, in particular, that the rotating wave approximation does not provide the correct expression, at the first perturbative order, of the evolution operator of the system.

Jozsef Garai, Tibor Gasparik

Experiments at 6-12 GPa showed that San Carlos olivine surrounded by carbon melts incongruently at 1400 C and higher temperatures, producing olivine with lower Fe contents, pyroxene, carbide, and carbonate melt. The relatively low melting temperature of 1400 C, independent of pressure, is consistent with carbonate melting. The new evidence for the reduced st

A. Semparithi, S. Keshavamurthy

Intermolecular dynamics of highly excited DCO (X^2A') is studied from a classical-quantum perspective using the effective spectroscopic Hamiltonian proposed recently by Trollch and Temps (Z. Phy. Chem. 215, 207 (2001)). This work focuses on the polyads P = 3 and P = 4 corresponding to excitation energies E_v ~ 5100 cm^-1 and 7000 cm^-1 respectively. The

L. G. Moretto, J. B. Elliott, L. Phair

We explore the effects of Coulomb interaction upon the nuclear liquid vapor phase transition. Because large nuclei (A>60) are metastable objects, phases, phase coexistence, and phase transitions cannot be defined with any generality and the analogy to liquid vapor is ill-posed for these heavy systems. However, it is possible to account for the Coulomb intera

Caiwan Shen, U. Lombardo, N. Van Giai, W. Zuo

The neutrino propagation in neutron stars is studied in the framework of the linear response method. The medium effects are treated in the non-relativistic Brueckner-Hartree-Fock approach either in the mean-field approximation or in the RPA. The residual interaction is expressed in terms of the Landau parameters extracted from the equation of state of spin-

P. Quentin, H. Laftchiev, D. Samsoen, I. N. Mikhailov

Using Chandrasekhar's S-type coupling between rotational and intrinsic vortical modes one may simply reproduce the HFB dynamical properties of rotating nuclei within Routhian HF calculations free of pairing correlations yet constrained on the relevant so-called Kelvin circulation operator. From the analogy between magnetic and rotating systems, one deriv

R. J. Furnstahl

This contribution is an advertisement for applying effective field theory (EFT) to many-body problems, including nuclei and cold atomic gases. Examples involving three-body interactions are used to illustrate how EFT's quantify and systematically eliminate model dependence, and how they make many-body calculations simpler and more powerful.

K. -H. Schmidt, J. Benlliure, D. Boilley, A. Heinz

Theoretical methods, interpretations and conclusions on the fission dynamics in a recent publication of H. Hofmann and F. A. Ivanyuk on the mean first passage time are critically considered.

Jian-Ye Liu, Yong-Zhong Xing, Wen-Jun Guo

Based on an isospin dependent quantum molecular dynamics model we studied the influence of a medium correction of an isospin dependent nucleon nucleon cross section on the fragmentation at the intermediate energy heavy ion collisions. We found that the medium correction from an isospin dependent nucleon nucleon cross section increases the dependence of the f

Jian-Ye Liu, Yong-Zhong Xing, Wen-Jun Guo

We study the isospin effects of the mean field and two-body collision on the nucleon emissions at the intermediate energy heavy ion collisions by using an isospin dependent transport theory. The calculated results show that the nucleon emission number $N_{n}$ depends sensitively the isospin effect of nucleon nucleon cross section and weakly on the isospin de

Yong-Zhong Xing, Jian-Ye Liu, Wen-Jun Guo

The influence of medium correction from an isospin dependent nucleon nucleon cross section on the fragmentation and nucleon emission in the intermediate energy heavy ion collisions was studied by using an isospin dependent quantum molecular dynamical model (IQMD). We found that the medium correction enhances the dependence of multiplicity of intermediate mas

Jian-Ye Liu, Wen-Jun Guo, Yong Zhong Xing, Hang Liu

The degree of isospin fractionation is measured by $(N/Z)_{n}$ / $(N/Z)_{N_{imf}}$, where $(N/Z)_{n}$ and $(N/Z)_{N_{imf}}$ are the saturated neutron-proton ratio of nucleon emissions (gas phase) and that of fragment emissions (liquid phase) in heavy ion collision at intermediate energy . The calculated results by using the isospin-dependent quantum molecula

Yuan-Nan Young, Hermann Riecke, Werner Pesch

We study hexagon patterns in non-Boussinesq convection of a thin rotating layer of water. For realistic parameters and boundary conditions we identify various linear instabilities of the pattern. We focus on the dynamics arising from an oscillatory side-band instability that leads to a spatially disordered chaotic state characterized by oscillating (whirling

P. G. Grinevich, P. M. Santini

This is the first of a series of papers devoted to the study of classical initial-boundary value problems of Dirichlet, Neumann and mixed type for the Nonlinear Schrödinger equation on the segment. Considering proper periodic discontinuous extensions of the profile, generated by suitable point-like sources, we show that the above boundary value problems can

Christian Gerard, Christian Jaekel

We construct interacting quantum fields in 1+1 space-time dimensions, representing charged or neutral scalar bosons at positive temperature and zero chemical potential. Our work is based on prior work by Klein and Landau and Hoegh-Krohn. Generalized path space methods are used to add a spatially cut-off interaction to the free system, which is described in t

Bertrand Eynard

We present a method, based on loop equations, to compute recursively, all the terms in the large $N$ topological expansion of the free energy for the 2-hermitian matrix model, in the case where the support of the density of eigenvalues is not connected. We illustrate the method by computing the free energy of a statistical physics model on a discretized toru

Ruth Haas, David Orden, Guenter Rote, Francisco Santos

Pointed pseudo-triangulations are planar minimally rigid graphs embedded in the plane with pointed vertices (adjacent to an angle larger than 180 degrees. In this paper we prove that the opposite statement is also true, namely that planar minimally rigid graphs always admit pointed embeddings, even under certain natural topological and combinatorial constrai

D. Khoshnevisan, D. A. Levin, P. J. Mendez-Hernandez

Motivated by the recent work of Benjamini, Haggstrom, Peres, and Steif (2003) on dynamical random walks, we: Prove that, after a suitable normalization, the dynamical Gaussian walk converges weakly to the Ornstein-Uhlenbeck process in classical Wiener space; derive sharp tail-asymptotics for the probabilities of large deviations of the said dynamical walk; a

Chongsheng Cao, Edriss S. Titi, Mohammed Ziane

In this paper we study a three dimensional thermocline planetary geostrophic ``horizontal" hyper--diffusion model of the gyre-scale midlatitude ocean. We show the global existence and uniqueness of the weak and strong solutions to this model. Moreover, we establish the existence of a finite dimensional global attractor to this dissipative evolution syste

Mark Davidson, Gestur Olafsson

Analysis of function spaces and special functions are closely related to the representation theory of Lie groups. We explain here the connection between the Laguerre functions, the Laguerre polynomials, and the Meixner-Pollacyck polynomials on the one side, and highest weight representations of Hermitian Lie groups on the other side. The representation theor

Wolfgang Pitsch, Jerome Scherer

We give a proof of the Jardine-Tillmann generalized group completion theorem. It is much in the spirit of the original homology fibration approach by McDuff and Segal, but follows a modern treatment of homotopy colimits, using as little simplicial technology as possible. We compare simplicial and topological definitions of homology fibrations.

Lars Andersson

Benedetti and Guadagnini have conjectured that the marked lenght spectrum of the constant mean curvature foliation $M_τ$ in a 2+1 dimensional flat spacetime $V$ with compact hyperbolic Cauchy surfaces converges, in the direction of the singularity, to that of the marked measure spectrum of the R-tree dual to the measured foliation corresponding to the transl

Daniel M. Pellegrino

In this note we obtain new coincidence theorems for absolutely summing multilinear mappings between Banach spaces. We also prove that our results, in general, can not be improved.

Fabio Martinelli, Alistair Sinclair, Dror Weitz

We give the first comprehensive analysis of the effect of boundary conditions on the mixing time of the Glauber dynamics in the so-called Bethe approximation. Specifically, we show that spectral gap and the log-Sobolev constant of the Glauber dynamics for the Ising model on an n-vertex regular tree with plus-boundary are bounded below by a constant independe

Ivar Ekeland

We study a special class of non-convex functions which appear in nonlinear elasticity; and we prove that they have well-defined Legandre transforms. Several examples are given, and an application to a nonlinear eigenvalue problem

B Coupet, H Gaussier, A Sukhov

We prove the existence of stationary discs in the ball for small almost complex deformations of the standard structure. We define a local analogue of the Riemann map and establish its main properties. These constructions are applied to study the local geometry of almost complex manifolds and their morphisms.

Paolo d'Alessandro

In a previous paper, published in 1992, a primal conical LP algorithm with exact finite coonvergence was presented. The underlying optimality condition requires tangency of two sets (an affine space and a cone). In the algorithm the two sets remain disjoint until the last step. This left open the possibility of developing an internal algorithm in which, by t

Tomohiro Yamada

This paper has been withdrawn by the author, due to a crucial error in the proof of Lemma 3.1.

Benoit Fresse

We prove that the bar construction of an $E_\infty$ algebra forms an $E_\infty$ algebra. To be more precise, we provide the bar construction of an algebra over the surjection operad with the structure of a Hopf algebra over the Barratt-Eccles operad. (The surjection operad and the Barratt-Eccles operad are classical $E_\infty$ operads.)

Ilya Kapovich, Richard Weidmann, Alexei Myasnikov

We introduce a combinatorial version of Stallings-Bestvina-Feighn-Dunwoody folding sequences. We then show how they are useful in analyzing the solvability of the uniform subgroup membership problem for fundamental groups of graphs of groups. Applications include coherent right-angled Artin groups and coherent solvable groups.

David Eppstein

We show that graph-theoretic thickness and geometric thickness are not asymptotically equivalent: for every t, there exists a graph with thickness three and geometric thickness >= t.

A. Vereshagin, V. Vereshagin

This is the 4-th paper in the series devoted to a systematic study of the problem of mathematically correct formulation of the rules needed to manage an effective field theory. Here we consider the problem of constructing the full set of essential parameters in the case of the most general effective scattering theory containing no massless particles with spi

Etera R. Livine, Robert Oeckl

We show how super BF theory in any dimension can be quantized as a spin foam model, generalizing the situation for ordinary BF theory. This is a first step toward quantizing supergravity theories. We investigate in particular 3-dimensional (p=1,q=1) supergravity which we quantize exactly. We obtain a super-Ponzano-Regge model with gauge group OSp(1|2). A mai

S. Willenbrock

I describe the surrounding landscape on the road to the CERN Large Hadron Collider. I revisit the milestones of hadron-collider physics, and from them draw lessons for the future. I recall the primary motivation for the journey - understanding the mechanism of electroweak symmetry breaking - and speculate that even greater discoveries may await us. I review

A. Zee

We propose parametrizations of the neutrino mixing matrix. We discuss several Ansatzes: in some of them $V_{e3}=0$ but in others $V_{e3}$ typically ``comes out'' to be of order $\simeq 0.05.$

Alexey A. Petrov

We review several key aspects of charm phenomenology which are important for the general program of determination of matrix elements of the Cabbibo-Kobayashi-Maskava (CKM) matrix. We argue that charm physics plays an important role in reducing uncertainties in non-perturbative QCD parameters whose values are required for understanding of underlying quark-lev

Fabio Siringo

By invoking the existence of a general custodial O(2) symmetry, a minimal Left-Right symmetric model based on the gauge group G=SU(2)L SU(2)R U(1)BL is shown to require the existence of only two physical Higgs bosons. The lighter Higgs is predicted to have a small mass which could be evaluated by standard perturbation theory. The fermionic mass matrices are

A. Bartl, S. Hesselbach, K. Hidaka, T. Kernreiter

We study the decays of top squarks (stop_{1,2}) and bottom squarks (sbottom_{1,2}) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A_t, A_b, mu and M_1. We show that including the corresponding phases substantially affects the branching ratios of stop_{1,2} and sbottom_{1,2} decays in a large domain of the MSSM parameter space. We

Maria Krawczyk

A (updated) summary of the Photon-Photon and Electron-Photon physics session is presented.

Hans Peter Nilles

Embedding hidden sector supergravity models in the framework of string theory leads to the appearance of axion-like degrees of freedom. Among them is the model independent axion of heterotic string theory. It has a decay constant of order of the Planck scale and could play the role of a quintessence field. In models allowing for the required $μ$ term in the

Hiroaki Sugiyama

A brief overview is given of theoretical analyses with neutrinoless double beta decay experiments. Theoretical bounds on the ``observable&#39;&#39;, <m>_betabeta, are presented. By using experimental bounds on <m>_betabeta, allowed regions are obtained on the m_l-cos{2theta_12} plane, where m_l stands for the lightest neutrino mass. It is shown that Majorana

P. Gonzalez, A. Valcarce, H. Garcilazo, J. Vijande

We perform a quark model calculation of the $b\bar{b}$ and $c\bar{c}$ spectra from a screened funnel potential form suggested by unquenched lattice calculations. A connection between the lattice screening parameter and an effective gluon mass directly derived from QCD is established. Spin-spin energy splittings, leptonic widths and radiative decays are also

David London, Nita Sinha, Rahul Sinha

We describe how the angular analysis of vector-vector final states in B decays provides theoretically clean techniques for determination of CP violating phases. The quantity $\sin^2 (2β+ γ)$ can be cleanly obtained from the time dependent study of decays such as B_d(t)->D^{*\pm} ρ^\mp, D^{*\pm} a_1^{\mp} etc. Similarly, one can use B_s(t)-> D_s^{*\pm} K^{*\m

David London, Nita Sinha, Rahul Sinha

We show that an angular analysis of B -> V1 V2 decays yields numerous tests for new physics in the decay amplitudes. Many of these new-physics observables are nonzero even if the strong phase differences vanish. For certain observables, neither time-dependent measurements nor tagging is necessary. Should a signal for new physics be found, one can place a low

The Soudan 2 Collaboration

The effects of oscillations of atmospheric muon neutrinos are observed in the 5.90 fiducial kiloton-year exposure of the Soudan 2 detector. An unbinned maximum likelihood analysis of the neutrino L/E distribution has been carried out using the Feldman-Cousins prescription. The probability of the no oscillation hypothesis is 5.8x10-4. The 90% confidence allow

Gerhard Raven

An overview of the observation of CP violation in the neutral B system, and the measurements of the CP violating asymmetry sin(2beta) with B to charmonium K^0_{S,L} events, performed by the BaBar and Belle experiments at the SLAC and KEK B factories is given. In addition, the measurements of sin(2beta) with several other modes are described, including B to p

Teresa Barillari

The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons has been studied using data taken at sqrt(s_ee) = 183 GeV and 189 GeV with the OPAL detector at LEP. Results are presented for proton-antiproton invariant masses, W, in the range 2.15 < W < 3.95 GeV. The cross-section measurements are compared with previous data a

A. L. Choudhury

We improved the approximation of the model of the wormhole generated physical universe constructed by Choudhury and Pendharkar. We show here that the negative pressure of the unphysical wormhole can generate the right physical condition to explain the correct sign of the deacceleration parameter $q_0$. The negative sign ofsign of $q_0$ implies an acceleratin

Edu Metz, Raimondas Lencevicius

Performance profiling consists of tracing a software system during execution and then analyzing the obtained traces. However, traces themselves affect the performance of the system distorting its execution. Therefore, there is a need to minimize the effect of the tracing on the underlying system&#39;s performance. To achieve this, the trace set needs to be o

Chung-chieh Shan

Wh-phrases in English can appear both raised and in-situ. However, only in-situ wh-phrases can take semantic scope beyond the immediately enclosing clause. I present a denotational semantics of interrogatives that naturally accounts for these two properties. It neither invokes movement or economy, nor posits lexical ambiguity between raised and in-situ occur

P. B. Blakie, J. V. Porto

The entropy-temperature curves are calculated for non-interacting bosons in a 3D optical lattice and a 2D lattice with transverse harmonic confinement for ranges of depths and filling factors relevant to current experiments. We demonstrate regimes where the atomic sample can be significantly heated or cooled by adiabatically changing the lattice depth. We in

Thomas la Cour Jansen, Shaul Mukamel

The identification of relevant collective coordinates is crucial for the interpretation of coherent nonlinear spectroscopies of complex molecules and liquids. Using an $\hbar$ expansion of Liouville space generating functions, we show how to factorize multitime nonlinear response functions into products of lower-order correlation functions of collective coor

G. D. Sanders, Y. Sun, C. J. Stanton, G. A. Khodaparast

Accurate determination of carrier densities in ferromagnetic semiconductors by Hall measurements is hindered by the anomalous Hall effect, and thus alternative methods are being sought. Here, we propose that cyclotron resonance (CR) is an excellent method for carrier density determination for InMnAs-based magnetic structures. We develop a theory for electron

Xiangyun Qiu, Simon J. L. Billinge, Carmen R. Kmety, John F. Mitchell

The atomic pair distribution function (PDF) technique is employed to probe the atomic local structural responses in naturally double layered manganites \lsmo in the doping range $0.54 \leq x \leq 0.80$. Our low temperature neutron powder diffraction measurements suggest the coexistence of two different Jahn-Teller (JT) distorted MnO$_6$ octahedra when its or

J. Ruostekoski, J. R. Anglin

We show how the length scale hierarchy, resulting from different interaction strengths in an optically-trapped spin-1 sodium-23 Bose-Einstein condensate, can lead to intriguing core deformations in singular topological defects. In particular, a point defect can be unstable with respect to the formation of a stable half-quantum vortex ring (an Alice ring), pr

Malte Henkel, Alan Picone, Michel Pleimling, Jeremie Unterberger

The generalization of dynamical scaling to local scale invariance is reviewed. Starting from a recapitulation of the phenomenology of ageing phenomena, the generalization of dynamical scaling to local scale transformation for any given dynamical exponent $z$ is described and the two distinct types of local scale invariance are presented. The special case $z=

Ramandeep S. Johal, Antoni Planes, Eduard Vives

The extended gaussian ensemble (EGE) is introduced as a generalization of the canonical ensemble. The new ensemble is a further extension of the Gaussian ensemble introduced by J. H. Hetherington [J. Low Temp. Phys. {\bf 66}, 145 (1987)]. The statistical mechanical formalism is derived both from the analysis of the system attached to a finite reservoir and f

G. Gyorgyi, P. C. W. Holdsworth, B. Portelli, Z. Racz

The extremal Fourier intensities are studied for stationary Edwards-Wilkinson-type, Gaussian, interfaces with power-law dispersion. We calculate the probability distribution of the maximal intensity and find that, generically, it does not coincide with the distribution of the integrated power spectrum (i.e. roughness of the surface), nor does it obey any of

Hans Behringer

Symmetry properties of the microcanonical entropy surface as a function of the energy and the order parameter are deduced from the invariance group of the Hamiltonian of the physical system. The consequences of these symmetries for the microcanonical order parameter in the high energy and in the low energy phases are investigated. In particular the breaking

Xia-Ji Liu, Hui Hu

We present a detailed study of the low-lying collective excitations of a spherically trapped Bose-Fermi mixture at finite temperature in the collisionless regime. The excitation frequencies of the condensate are calculated self-consistently using the static Hartree-Fock-Bogoliubov theory within the Popov approximation. The frequency shifts and damping rates

G. Seibold

We investigate the charge-instabilities of the Hubbard-Holstein model with two coupled layers. In this system the scattering processes naturally separate into contributions which are either symmetric or antisymmetric combinations with respect to exchange of the layers. It turns out that the short-range strong correlations suppress finite wave-vector nesting

G. Seibold, J. Lorenzana

Based on an unrestricted Gutzwiller approximation (GA) we investigate the stripe orientation and periodicity in an extended one-band Hubbard model. A negative ratio between next-nearest and nearest neighbor hopping t&#39;/t, as appropriate for cuprates, favors partially filled (metallic) stripes for both vertical and diagonal configurations. At around optima

Lucien Saviot, Daniel B Murray, Maria Del Carmen Marco De Lucas

Vibrational mode frequencies and damping are calculated for an elastic sphere embedded in an infinite, homogeneous, isotropic elastic medium. Anisotropic elasticity of the sphere significantly shifts the frequencies in comparison to simplified calculations that assume isotropy. New low frequency Raman light scattering data are presented for silicon spheres g

Wonkee Kim, F. Marsiglio

Effects of an incoming spin-polarized current on a magnetic moment are explored. We found that the spin torque occurs only when the incoming spin changes as a function of time inside of the magnetic film. This implies that some modifications are necessary in a phenomenological model where the coefficient of the spin torque term is a constant, and the coeffic

M. V. Entin, L. I. Magarill, M. M. Mahmoodian

We have studied the distribution of equilibrium edge current density in 2D system in a strong (quantizing) magnetic field. The case of half plane in normal magnetic field has been considered. The transition from classical strong magnetic field to ultraquantum limit has been investigated. We have shown that the edge current density oscillates and decays with

Munehiko Maeda, Keiji Saito, Seiji Miyashita, Hans De Raedt

We compute the electric conductivity of nanowires in the presence of magnetic domain walls by the method of wave packet propagation. We demonstrate that the propagation through the wire depends on the initial state used in the wave packet simulation. We propose a procedure, based on the Landauer formula, to reduce this dependence. Direct numerical calculatio

David H. Wolpert

This paper presents a novel way to approximate a distribution governing a system of coupled particles with a product of independent distributions. The approach is an extension of mean field theory that allows the independent distributions to live in a different space from the system, and thereby capture statistical dependencies in that system. It also allows

M. M. Rosario, H. Wang, Yu. Zadorozhny, Y. Liu

We report the observation of a quantum phase transition (QPT), tuned by a parallel magnetic field, between a superconducting and metallic state in Au0.7In0.3 films of very low normal-state sheet resistance (< 90 Ohms). These films can be modeled as a random array of superconductor-normal metal-superconductor (SNS) junctions. Electrical transport and tunnelin

J. W. Freeland, R. H. Kodama, M. Vedpathak, S. C. Erwin

We report direct experimental evidence showing induced magnetic moments on Ge at the interface in an Fe/Ge system. Details of the x-ray magnetic circular dichroism and resonant magnetic scattering at the Ge L edge demonstrate the presence of spin-polarized {\it s} states at the Fermi level, as well as {\it d} character moments at higher energy, which are bot

Pablo Gleiser, Leon Danon

Using a database of jazz recordings we study the collaboration network of jazz musicians. We define the network at two different levels. First we study the collaboration network between individuals, where two musicians are connected if they have played in the same band. Then we consider the collaboration between bands, where two bands are connected if they h

Felipe Jimenez-Angeles, Rene Messina, Christian Holm, Marcelo Lozada-Cassou

A novel integral equations approach is applied for studying ion pairing in the restricted primitive model (RPM) electrolyte, i. e., the three point extension (TPE) to the Ornstein-Zernike integral equations. In the TPE approach, the three-particle correlation functions $g^{[3]}({\bf r}_{1},{\bf r}_{2},{\bf r}_{3})$ are obtained. The TPE results are compared

Kazumi Nishimura, Edison Liang, S. Peter Gary

Charge separation effects in the expansion of magnetized relativistic electron-ion plasmas into a vacuum are examined using 2-1/2-dimensional particle-in-cell plasma simulations. The electrostatic field at the plasma surface decelerates electrons and accelerates ions. A fraction of the surface electrons are trapped and accelerated by the pondermotive force o

F. Garcia-Arredondo, Adam Frank

We present three-dimensional hydrodynamic simulations of the interaction of a slow wind from an asymptotic giant branch(AGB) star and a jet blown by an orbiting companion. The jet or &#34;Collimated Fast Wind&#34; is assumed to originate from an accretion disk which forms via Bondi accretion of the AGB wind or Roche lobe overflow. We present two distinct reg

H. E. S. S. collaboration

This preprint encompasses 14 individual contributions of the H.E.S.S. collaboration to the 28th ICRC: Status, Performance of the cameras, Observation of Galactic and extra Galactic sources, Performance of the telescope, Application of a shower fitting algorithm, DAQ, Mirror alignment, Calibration, Pointing, Flat-fielding with LEDs, Atmospheric monitoring, LI

Gary J. Ferland

The emission-line spectrum of a quasar is most likely emitted by an ensemble of photoionized clouds moving with a variety of velocities, with a range of densities and distances from the central object. The state of the art in this field is to first compute the emission from a single cloud, and then prescribe a mix of clouds to reproduce line intensities, pro

J. -F. Donati, A. Collier Cameron, P. Petit

This paper reports positive detections of surface differential rotation on two rapidly rotating cool stars at several epochs, by using stellar surface features (both cool spots and magnetic regions) as tracers of the large scale latitudinal shear that distorts the convective envelope in this type of stars. We also report definite evidence that this different

M. Odenkirchen, E. K. Grebel, W. Dehnen, H. -W. Rix

Using wide-field photometric data from the Sloan Digital Sky Survey (SDSS) we recently showed that the Galactic globular cluster Palomar 5 is in the process of being tidally disrupted. Its tidal tails were initially detected in a 2.5 degree wide band along the celestial equator. A new analysis of SDSS data for a larger field now reveals that the tails of Pal

Y. Fenner, B. K. Gibson, H. -c. Lee, A. I. Karakas

The abundance of the neutron-rich magnesium isotopes observed in metal-poor stars is explained quantitatively with a chemical evolution model of the local Galaxy that considers - for the first time - the metallicity-dependent contribution from intermediate mass stars. Previous models that simulate the variation of Mg isotopic ratios with metallicity in the s

Andrei O. Barvinsky, Alexander Yu. Kamenshchik, Claus Kiefer, Andreas Rathke

One of the most interesting features of braneworld models is the existence of massive gravitational modes in addition to the usual massless one. Mixing of the modes which depends nontrivially on the inter-brane distance can be interpreted as radion-induced gravitational-wave oscillations, a classical analogy to meson and neutrino oscillations. We show that t

Geraint F. Lewis, Scott C. Chapman, Zdenka Kuncic

The broad absorption line (BAL) features seen in a small fraction of quasar optical/UV spectra are attributed to bulk outflows away from the quasar core. Observational evidence suggests that dust plays a key role in these systems, although whether the inferred dust properties are a signature of orientation effects or whether they are indicative of an evoluti

A. D. Dolgov, M. Kawasaki

We propose a model with a compensating scalar field whose back reaction to the cosmological curvature cancels possible vacuum energy density down to the terms of the order of the time dependent critical energy density. Thus the model simultaneously solves the mystery of the compensation of vacuum energy with the accuracy of 120 orders of magnitude and explai

Amber N. Benson, Howard L. Richards, T. L. Einstein

The Pairwise Einstein Model (PEM) of steps not only justifies the use of the Generalized Wigner Distribution (GWD) for Terrace Width Distributions (TWDs), it also predicts a specific form for the Step Position Distribution (SPD), i.e., the probability density function for the fluctuations of a step about its average position. The predicted form of the SPD is