September 2003 arXiv papers — page 7

David Craig, James B. Hartle

A sum-over-histories generalized quantum theory is developed for homogeneous minisuperspace type A Bianchi cosmological models, focussing on the particular example of the classically recollapsing Bianchi IX universe. The decoherence functional for such universes is exhibited. We show how the probabilities of decoherent sets of alternative, coarse-grained his

S. Chacko, D. G. Kanhere, V. V. Paranjape

We present a systematic study of the geometries, energetics, electronic structure and bonding in various Al-Li clusters viz. AlnLin ($n$=1-11), Al$_2^-$, Al$_2^{2-}$, Al$_2$Li, Al$_2$Li$^-$, and Al6Li8 using Born-Oppenheimer molecular dynamics within the framework of density functional theory. The growth pattern in these clusters is divided in two broad cate

Kensuke Kobayashi, Hisashi Aikawa, Shingo Katsumoto, Yasuhiro Iye

The Fano effect, which occurs through the quantum-mechanical cooperation between resonance and interference, can be observed in electron transport through a hybrid system of a quantum dot and an Aharonov-Bohm ring. While a clear correlation appears between the height of the Coulomb peak and the real asymmetric parameter $q$ for the corresponding Fano linesha

Rodolfo A. Diaz, R. Martinez, F. Ochoa

A complete study of the Higgs sector of the $SU(3)_{c}\otimes SU(3)_{L}\otimes U(1)_{X}$ model is carried out, obtaining all possible cases of vacuum expectation values that permit the spontaneous symmetry breaking pattern$ SU(3)_{L}\otimes U(1)_{X}\to SU(2)_{L}\otimes U(1)_{Y}\to U(1)_{Q}.$ We find the most general Higgs potentials that contain three triple

E. Arrigoni, E. Fradkin, S. A. Kivelson

It is shown, using asymptotically exact methods, that the two dimensional repulsive Hubbard model with strongly modulated interactions exhibits ``high temperature superconductivity". Specifically, the explicit modulation, which has the same symmetry as period 4 bond-centered stripes, breaks the system into an alternating array of more and less heavily ho

Kartik Srinivasan, Paul E. Barclay, Matthew Borselli, Oskar Painter

A two-dimensional photonic crystal semiconductor microcavity with a quality factor Q ~ 40,000 and a modal volume Veff ~ 0.9 cubic wavelengths is demonstrated. A micron-scale optical fiber taper is used as a means to probe both the spectral and spatial properties of the cavity modes, allowing not only measurement of modal loss, but also the ability to ascerta

L. -M. Duan, H. J. Kimble

We propose a scheme for scalable photonic quantum computation based on cavity assisted interaction between single-photon pulses. The prototypical quantum controlled phase-flip gate between the single-photon pulses is achieved by successively reflecting them from an optical cavity with a single-trapped atom. Our proposed protocol is shown to be robust to prac

Z. Hradil, J. Rehacek

Diffraction on the slit can be interpreted in accordance with the Heisenberg uncertainty principle. This elementary example hints at the importance of the information theory for the quantum physics. The role played by one particularly interesting measure of information -- the Fisher information -- in quantum measurements is further discussed in the context o

M. S. Shahriar, P. Pradhan, V. Gopal, G. Pati

Recently, we have shown theoretically [1] as well as experimentally [2] how the phase of an electromagnetic field can be determined by measuring the population of either of the two states of a two-level atomic system excited by this field, via the so-called Bloch-Siegert oscillation resulting from the interference between the co- and counter-rotating excitat

Chi Ming Yang

In the present work, 16 genetic code doublets and their cognate amino acids in the genetic code are fitted into a polyhedron model. Based on the structural regularity in nucleobases, and by using a series of common-sense topological approaches to rearranging the Hamiltonian-type graph of the codon map, it is identified that the degeneracy of codons and the i

Konstantin Klemm, Stefan Bornholdt

We compare asynchronous vs. synchronous update of discrete dynamical networks and find that a simple time delay in the nodes may induce a reproducible deterministic dynamics even in the case of asynchronous update in random order. In particular we observe that the dynamics under synchronous parallel update can be reproduced accurately under random asynchrono

M. Siefert, J. Peinke

We address the problem of differences between longitudinal and transverse velocity increments in isotropic small scale turbulence. The relationship of these two quantities is analyzed experimentally by means of stochastic Markovian processes leading to a phenomenological Fokker- Planck equation from which a generalization of the Karman equation is derived. F

C. G. Bao, T. Y. Shi

The constraints imposed by symmetry on the open channels of dipositronium has been studied, and the symmetry-adapted lowest open channel of each quantum state has been identified. Based on this study, the existence of two more 0^+ bound states has been theoretically confirmed, and a 0^+ narrow resonance has been predicted. A variational calculation has been

Alejandro Rivero

While similarities do naturally exist between tao and other philosophical systems, for the specific case of Democritus we can argue also the chronological parallels, the parallels in the posterior development (alchemy and mathematics) and the textual parallelism.

P. Barletta, A. Fabrocini, A. Kievsky, J. Navarro

The He2-SF6 trimers, in their different He isotopic combinations, are studied both in the framework of the correlated Jastrow approach and of the Correlated Hyperspherical Harmonics expansion method. The energetics and structure of the He-SF6 dimers are analyzed, and the existence of a characteristic rotational band in the excitation spectrum is discussed, a

Colin Morningstar, Mike Peardon

Techniques for efficient computation of the scalar glueball mass on the lattice are described. Directions and physics goals of proposed future calculations will be outlined.

H. Ganev, V. P. Garistov, A. I. Georgieva

In the framework of the symplectic extension of the Interacting Vector Boson Model (IVBM) a good description of the first excited positive and negative parity bands of the nuclei in the rare earth and the actinide region is achieved. The bands investigated in the model are extended to very high angular momenta as a result of their consideration as "yrast

A. Kievsky, M. Viviani, L. E. Marcucci

The electromagnetic potential consisting in the Coulomb plus the magnetic moment interactions between two nucleons is studied in nucleon-deuteron scattering. For states in which the relative N-d angular momentum L has low values the three--nucleon problem has been solved using the correlated hyperspherical harmonic expansion basis. For states in which the an

E. Tomasi-Gustafsson, G. I. Gakh, A. P. Rekalo, M. P. Rekalo

We generalize the recoil polarization method for the determination of the proton form factor to the case of the disintegration of vector polarized deuterons by longitudinally polarized electrons, $\vec d(\vec e, e'n)p$. We suggest to measure for this reaction, in the kinematics of quasi-elastic $en$-scattering, the ratio $R_{xz}=A_x/A_z$ of the asymmetri

Haruki Kurasawa, Toshio Suzuki

The non energy-weighted Gamow-Teller(GT) sum rule is satisfied in relativistic models, when all nuclear density-dependent terms, including Pauli blocking terms from nucleon-antinucleon excitations, are taken into account in the RPA correlation function. The no-sea approximation is equivalent to this approximation for the giant GT resonance state and satisfie

Vladimir P. Garistov

Recently the classification of low-lying excited 0+ states in even even deformed nuclei has been done. The available experimental data were represented as the energies parabolic distributed by number of monopole excitations. With other words each 0+ state now is determined as the collective state with the corresponding number of monopole type phonons n . In

Ionel Stetcu, Calvin W. Johnson

We investigate reliability of Gamow-Teller transition strengths computed in the proton-neutron random phase approximation, comparing with exact results from diagonalization in full $0\hbarω$ shell-model spaces. By allowing the Hartree-Fock state to be deformed, we obtain good results for a wide variety of nuclides, even though we do not project onto good ang

P. Winter, H. H. Adam, A. Budzanowski, R. Czyzykiewicz

A first measurement of the analysing power in the reaction p(pol)p --> pp eta near the production threshold has been performed at the internal facility COSY-11 at the COoler SYnchrotron COSY.

Alex Roxin, Hermann Riecke, Sara A. Solla

We study the dynamics of excitable integrate-and-fire neurons in a small-world network. At low densities $p$ of directed random connections, a localized transient stimulus results in either self-sustained persistent activity or in a brief transient followed by failure. Averages over the quenched ensemble reveal that the probability of failure changes from 0

C. Dembowski, B. Dietz, H. -D. Graef, H. L. Harney

In a recent paper [Phys. Rev. E 67, 026204 (2003)], Rotter calculates the geometric phases that are picked up by the eigenvectors of a two-state quantum system when an exceptional point is encircled. In addition to the geometric phases observed by Dembowski et al. in a microwave cavity experiment [Phys. Rev. Lett. 86, 787 (2001)], she finds a phase factor of

Jean-Bernard Zuber

New conjectures are proposed on the numbers of FPL configurations pertaining to certain types of link patterns. Making use of the Razumov and Stroganov Ansatz, these conjectures are based on the analysis of the ground state of the Temperley-Lieb chain, for periodic boundary conditions and so-called ``identified connectivities'', up to size $2n=22$.

Antonino Sciarrino

In the framework of the crystal basis model of the genetic code, where each codon is assigned to an irreducible representation of $U_{q \to 0}(sl(2) \oplus sl(2))$, single base mutation matrices are introduced. The strength of the mutation is assumed to depend on the "distance" between the codons. Preliminary general predictions of the model are comp

Sophie Morier-Genoud

Let $G$ be a complex simply connected semisimple Lie group, and let $B_V$ be the canonical base of a Weyl module $V$ of $G$. We calculate explicitely the action of the longest element $w_0$ of the Weyl group on $B_V$ in terms of parametrizations. The method is based on results of Berenstein and Zelevinsky on the geometric lifting.

Gregory Lupton, Samuel Bruce Smith

The notion of a cyclic map g: A -> X is a natural generalization of a Gottlieb element in pi_n(X). We investigate cyclic maps from a rational homotopy theory point of view. We show a number of results for rationalized cyclic maps which generalize well-known results on the rationalized Gottlieb groups.

Tien-Cuong Dinh

Let (F_n) be a sequence of (multivalued) meromorphic maps between compact Kaehler manifolds X1 and X2. We study the asymptotic distribution of preimages of points by F_n and the asymptotic distribution of fixed points for multivalued self-maps of a compact Riemann surface. Let (Z_n) be a sequence of holomorphic images of the projective space P^s in a project

Baruch Solel

We prove that two quiver operator algebras can be isometrically isomorphic only if the quivers (=directed graphs) are isomorphic. We also show how the graph can be recovered from certain representations of the algebra.

B E Rhoades, Ekrem Savas

We obtain a set of necessary and sufficient conditions for $| \bar{N}, p_{n} |_{k} $ to imply $|\bar{N}, q_{n} |_{s}$ for $1 < k \leq s < \infty$. Using this result we establish several inclusion theorems as well as conditions for the equivalence of $| \bar {N}, p_{n} |_{k}$ and $|\bar{N},q_{n} |_{s}$.

B. Abdesselam, R. Chakrabarti, A. Hazzab, A. Yanallah

We develop a generic reprersentation-independent contraction procedure for obtaining, for instance, $R_{\sf h}$ and $L$ operators of arbitrary dimensions for the quantized ${\cal U}_{\sf h}(osp(2|1))$ algebra corresponding to the classical $r_2$ matrix from the pertinent quantities of the standard q-deformed ${\cal U}_q(osp(2|1))$ algebra. Also the quantized

Kiumars Kaveh

Let X \subset Proj(V) be a projective spherical G-variety, where V is a finite dimensional G-module and G = SP(2n, C). In this paper, we show that X can be deformed, by a flat deformation, to the toric variety corresponding to a convex polytope Δ(X). The polytope Δ(X) is the polytope fibred over the moment polytope of X with the Gelfand-Cetlin polytopes as f

Shankar Venkataramani

We study investigate a long, thin rectangular elastic membrane that is bent through an angle $2 α$, using the Foppl--von Karman ansatz in a geometrically linear setting. We study the associated variational problem, and show the existence of a minimizer for the elastic energy. We also prove rigorous upper and lower bounds for the minimum energy of this config

Peter Brinkmann

We present an explicit sequence of pseudo-Anosov maps $ϕ_k: S_{2k}\to S_{2k}$ of surfaces of genus $2k$ whose growth rates converge to one.

Roland Bacher

We describe and prove uniqueness of a natural homomorphism between some groups associated to finite sets.

Joel Bellaiche, Philippe Graftieaux

We prove, for the form of unitary group in three variables attached to a CM extension which is compact at infinity, a level-raising theorem analogous to the one of Taylor (inv. math. 98, 265-280) in the case of a quaternion algebra. We give an application to non tempered automorphic forms.

Lei Ni

We derive the entropy formula for the linear heat equaiton on complete Riemannian manifolds with nonnegative Ricci curvature. As applications, we study the relation between the value of entropy and the volume of balls of various scales. The results are simpler version, without Ricci flow, of Perelman&#39;s recent results on volume non-collapsing.

Jared E. Anderson, Mikhail Kogan

We study, in type A, the algebraic cycles (MV-cycles) discovered by I. Mirković and K. Vilonen [MV]. In particular, we partition the loop Grassmannian into smooth pieces such that the MV-cycles are their closures. We explicitly describe the points in each piece using the lattice model of the loop Grassmannian in type A. The partition is invariant under the a

Matvei Libine

Let G_R be a Lie group acting on an oriented manifold M, and let $ω$ be an equivariantly closed form on M. If both G_R and M are compact, then the integral $\int_M ω$ is given by the fixed point integral localization formula (Theorem 7.11 in [BGV]). Unfortunately, this formula fails when the acting Lie group G_R is not compact: there simply may not be enough

Henrique Bursztyn, Stefan Waldmann

We study deformations of invertible bimodules and the behavior of Picard groups under deformation quantization. While K_0-groups are known to be stable under formal deformations of algebras, Picard groups may change drastically. We identify the semiclassical limit of bimodule deformations as contravariant connections and study the associated deformation quan

Morihiko Saito

We study Deligne&#39;s conjecture on the monodromy weight filtration on the nearby cycles in the mixed characteristic case, and reduce it to the nondegeneracy of certain pairings in the semistable case. We also prove a related conjecture of Rapoport and Zink which uses only the image of the Cech restriction morphism, if Deligne&#39;s conjecture holds for a g

Inyong Cho, Alexander Vilenkin

Numerical solutions of Einstein, scalar, and gauge field equations are found for static and inflating defects in a higher-dimensional spacetime. The defects have $(3+1)$-dimensional core and magnetic monopole configuration in $n=3$ extra dimensions. For symmetry-breaking scale $η$ below the critical value $η_c$, the defects are characterized by a flat worlds

L. N. Granda

We propose a massless nonminimally coupled scalar field as a mechanism for stabilizing the size of the extradimension in the Randall-Sundrum I scenario. Without needing to introduce self interactions terms we obtain a potential for the modulus field that sets the size of the fifth dimension. The minumum of this potential yields appropriate values of the comp

V. Branchina, K. A. Meissner, G. Veneziano

We combine old ideas about exact renormalization-group-flow (RGF) equations with the Vilkovisky-De Witt (VDW) approach to reparametrization invariant effective actions and arrive at a new, exact, gauge-invariant RGF equation. The price to be paid for such a result is that both the action and the RGF equation depend explicitly upon the base point (in field sp

S. Tamaryan, H. J. W. Mueller-Kirsten, D. K. Park

The Born--Infeld theory of a D3-brane intersecting with(p,q) strings is reconsidered. From the assumption that the electromagnetic fields are those of a dyon, and using the kappa invariance of the action, the explicit scalar field and its charge are derived. Considering perturbations orthogonal to both branes, the SL(2,Z)-invariant S-matrix is obtained. Owin

Paul Koerber, Stijn Nevens, Alexander Sevrin

We study two-dimensional supersymmetric non-linear sigma-models with boundaries. We derive the most general family of boundary conditions in the non-supersymmetric case. Next we show that no further conditions arise when passing to the N=1 model. We present a manifest N=1 off-shell formulation. The analysis is greatly simplified compared to previous studies

P. Fonseca, A. Zamolodchikov

We show that the celebrated Painleve equations for the Ising correlation functions follow in a simple way from the Ward Identities associated with local Integrals of Motion of the doubled Ising field theory. We use these Ward Identities to derive the equations determining the matrix elements of the product $σ(x)σ(x&#39;)$ between any particle states. The res

W. F. Chagas-Filho

We study the space-time invariances of the bosonic relativistic particle and bosonic relativistic string using general formulations obtained by incorporating the Hamiltonian constraints into the formalism. We point out that massless particles and tensionless strings have a larger set of space-time invariances than their massive and tensionful partners, respe

Mrinal Dasgupta

We provide a brief review of the current status of resummed predictions for QCD final state observables such as event shapes and jet rates in a variety of different hard processes. Particular emphasis is given to more recent developments such as the study of non global observables, development of generalized resummation formulae and resummations for new type

Werner Vogelsang

We briefly review some of the recent developments in QCD spin physics.

M. A. Braun

Nucleus-nucleus interaction is studied in the framework of the perturbative QCD with large number of colours and a fixed coupling constant. The pomeron tree diagrams are summed by an effective field theory. The classical field equations are solved by iteration procedure, which is found convergent in a restricted domain of not too high energies and atomic num

Thomas Konstandin, Tomislav Prokopec, Michael G. Schmidt

The first principle derivation of kinetic transport equations suggests that a CP-violating mass term during the electroweak phase transition can induce axial vector currents. Since the important terms are of first order in gradients there is a possibility to construct new rephasing invariants that are proportional to the CP phase in the Cabibbo-Kobayashi-Mas

U. D&#39;Alesio, F. Murgia

The role of intrinsic transverse momentum both in unpolarized and polarized processes is discussed. We consider inclusive cross sections for pion production in hadronic collisions and for Drell-Yan processes. We reanalyze transverse single spin asymmetries (SSA) in inclusive pion production, p(transv. polarized) p --> pion + X, in terms of Sivers effect and

P. Faccioli, T. A. DeGrand

We present the results of a recent investigation of the short-distance structure of non-perturbative interaction between light quarks. We analyze the connection between topology and the dynamics responsible for the spontaneous breaking of chiral symmetry. By measuring some appropriate correlation functions on the lattice, we provide compelling evidence for i

R. Sghedoni

We present the complete calculation of the transverse momentum distribution for the decay b->s Gamma. The contributions of the leading operator O_7 are computed: infrared logarithms are resummed with next-to-leading accuracy, according to usual techniques of resummation. Non logarithmic terms are evaluated to O(alpha_S) by calculating one loop diagrams.

A. K. Giri, R. Mohanta

Motivated by the possible discrepancy between the observed CP asymmetry and that of standard model expectation in the decay mode B^0 -> phi K_S, we study the corresponding vector vector decay mode B^0 -> phi K^*. In order to obtain decisive information regarding the CP violating effect, we made the angular distribution analysis of the decay products, where b

K. Terasaki

By assigning the narrow scalar resonance (which has been recently observed at the B-factories) to one of iso-triplet four-quark mesons containing a charm quark, two body decays of the four-quark mesons are studied. It is predicted that some of them can be observed as narrow resonances.

Stefano Frixione, Bryan R. Webber

This is the user&#39;s manual of MC@NLO 2.2. This package is a practical implementation, based upon the HERWIG event generator, of the MC@NLO formalism, which allows one to incorporate NLO QCD matrix elements consistently into a parton shower framework. Processes available in this version include the hadroproduction of Higgs bosons, single vector bosons, vec

R. W. Gothe, S. Nussinov

We argue that the lightest isospin 1/2 partners of the Z^+(1530) s(bar)uudd penta-quark predicted by Diakonov, Petrov and Polyakov are not the N(1710) mixed anti-decuplet states, but the pure non-strange u(bar)(ud)(ud) and d(bar)(ud)(ud) penta-quark states which may lie as low as 1200 MeV. The expected low width of a few MeV of such a putative state may expl

Sh. Mamedov

The Dirac equation in a chromomagnetic field is solved for colored particle moving in a limited space volume. Quantized energy levels and the corresponding wave functions are found for backgrounds both directed along third axes and having spherical symmetry. It was shown interrelation with the case of motion in an infinite space volume.

Justin Foley, Alan O Cais, Mike Peardon, Sinead M. Ryan

Results from simulations of quarkonia and heavy-light mesons on an anisotropic lattice are presented. The improved quark action and action-parameter tuning used in this study are discussed.

Sinya Aoki, Yasuhisa Kayaba, Yoshinobu Kuramashi

We present the results for a perturbative determination of mass dependent improvement coefficients $ν$, $r_s$, $c_E$ and $c_B$ in a relativistic heavy quark action, which we have designed to control $m_Qa$ errors by extending the on-shell $O(a)$ improvement program to the case of $m_Q \gg Λ_{\rm QCD}$, where $m_Q$ is the heavy quark mass. The parameters $ν$

Shinji Takeda, Sinya Aoki, Kiyotomo Ide

We perturbatively determine O($a$) boundary improvement coefficients at 1-loop for the Schrödinger Functional coupling with improved gauge actions. These coefficients are required to implement the 1-loop O($a$) improvement in full QCD simulations for the coupling with the improved gauge actions. To this order, lattice artifacts of the step scaling function (

Y. Iwasaki, K. Kanaya, S. Kaya, S. Sakai

We investigate the phase structure of lattice QCD for the general number of flavors in the parameter space of gauge coupling constant and quark mass, employing the one-plaquette gauge action and the standard Wilson quark action. Performing a series of simulations for the number of flavors $N_F=6$--360 with degenerate-mass quarks, we find that when $N_F \ge 7

Alberto Reis

This work is a direct and model-independent measurement of the low mass $π^+π^-$ phase motion in the $D^+ \to π^-π^+π^+$ decay. The results show a strong phase variation, compatible with an isoscalar $σ(500)$ meson. This result confirms the previous Fermilab E791 result which found evidence for the existence of this scalar particle using a full Dalitz-plot a

Rinat A. Daishev, Winfried Zimdahl

We consider the homogeneous and isotropic cosmological fluid dynamics which is compatible with a homothetic, timelike motion, equivalent to an equation of state $ρ+ 3P = 0$. By splitting the total pressure $P$ into the sum of an equilibrium part $p$ and a non-equilibrium part $Π$, we find that on thermodynamical grounds this split is necessarily given by $p

M. J. Pareja

For relativistic stars rotating slowly and differentially with a positive angular velocity, some properties in relation to the positiveness of the rate of rotational dragging and of the angular momentum density are derived. Also, a new proof for the bounds on the rotational mass-energy is given.

Scott Funkhouser

If a physical significance should be attributed to the cosmological large number relationship obtained from Sciama&#39;s formulation of Mach&#39;s Principle, then a number of interesting physical conclusions may be drawn. The Planck length is naturally obtained as the amplitude of waves in a medium whose properties are implied by the relationship. The relati

S. A. Jafari, G. Baskaran

Using tight binding band picture for 2D graphite, and the Hubbard interaction, recently we obtained a gapless, neutral spin-1 collective mode in graphite \cite{SZS}. In this paper we present a detailed RPA analysis of the Neutron Scattering cross section for this collective mode. Near $K-$point and very close to $Γ-$point, the intensity of neutron scattering

J. A. Méndez-Bermúdez, G. A. Luna-Acosta, F. M. Izrailev

We study chaotic properties of eigenstates depending on the degree of complexity in boundaries of a 2D periodic billiard. Main attention is paid to the situation when the motion of a classical particle is strongly chaotic. Our approach allows to explore the transition from deterministic to disordered chaos, and to link chaos to the degree of ergodicity in ei

V. Gurarie, A. Altland

We study the spectral and transport properties of magnons in a model of a disordered magnet called Mattis glass, at vanishing average magnetization. We find that in two dimensional space, the magnons are localized with the localization length which diverges as a power of frequency at small frequencies. In three dimensional space, the long wavelength magnons

Domingos H. U. Marchetti, Claudio F. S. Rodrigues

We give a self-contained exposition of the combinatorial solution of quantum mechanical systems of coupled spins on a one-dimensional lattice. Using Trotter formula, we write the partition function as a generating function of a spanning subgraph of a two-dimensional lattice and solve the combinatorial problem by the method of Pfaffians provided the weights s

B. Ya. Gorodilov

The experimental data on the thermal conductivity of ortho-parahydrogen solutions are analyzed on the basis of a relaxation-time model taking account of configurational relaxation of the ortho subsystem. The influence of configurational relaxation on the thermal conductivity is analyzed using resonance scattering of phonons by pair clusters of orthomolecules

Alexander V. Avdeenkov

We investigate mean-field effects in two- component trapped Fermi gases in the superfluid phase, in the vicinity of s-wave Feshbach resonances. Within the resonance superfluidity approach (Holland et al., 2001) we calculate the ground state energy and the heat capacity as function of temperature. Heat capacity is analyzed for different trap aspect ratios. We

Igor I. Smolyaninov

Nonlinear optical behavior of recently introduced surface plasmon toy black hole models has been considered. Physical realization of these models involves droplets of liquid on a metal surface, which supports propagation of surface plasmons. Such droplets are shown to exhibit strongly enhanced nonlinear optical behavior in the frequency range near the surfac

Y. Bugoslavsky, Y. Miyoshi, G. K. Perkins, A. D. Caplin

We have performed a comparative study of two thin films of magnesium diboride (MgB2) grown by different techniques. The critical current density at different temperatures and magnetic fields was evaluated from magnetisation curves, the structure of superconducting order parameter was obtained from point-contact spectroscopy, and the scattering rates were eva

L. I. Plimak, M. Fleischhauer, M. K. Olsen

We study the occupation numbers and number fluctuations of ultra-cold atoms in deep optical lattices for finite temperatures within the Bose-Hubbard model. Simple analytical expressions for the mean occupation number and number fluctuations are obtained in the weak-hopping regime using an interpolation between results from different perturbation approaches i

F. Penna, J. Dzubiella, P. Tarazona

The Dynamic Density Functional (DDF) theory and standard Brownian dynamics simulations (BDS) are used to study the drifting effects of a colloidal particle in a polymer solution, both for ideal and interacting polymers. The structure of the stationary density distributions and the total induced current are analyzed for different drifting rates. We find good

Steven C. Erwin

A new structural model for the Si(111)5x2-Au reconstruction is proposed and analyzed using first-principles calculations. The basic model consists of a &#34;double honeycomb chain&#34; decorated by Si adatoms. The 5x1 periodicity of the honeycomb chains is doubled by the presence of a half-occupied row of Si atoms that partially rebonds the chains. Additiona

E. Gershnabel, N. Katz, R. Ozeri, E. Rowen

We propose and demonstrate an echo method to reduce the inhomogeneous linewidth of Bogoliubov excitations, in a harmonically-trapped Bose-Einstein condensate. Our proposal includes the transfer of excitations with momentum +q to -q using a double two photon Bragg process, in which a substantial reduction of the inhomogeneous broadening is calculated. Further

Michael Boss, Helmut Elsinger, Martin Summer, Stefan Thurner

We provide an empirical analysis of the network structure of the Austrian interbank market based on a unique data set of the Oesterreichische Nationalbank (OeNB). We show that the contract size distribution follows a power law over more than 3 decades. By using a novel &#39;&#39;dissimilarity&#39;&#39; measure we find that the interbank network shows a commu

Stefan Thurner, Rudolf Hanel, Stefan Pichler

In the context of understanding the nature of the risk transformation process of the financial system we propose an iterative risk-trading game between several agents who build their trading strategies based on a general utility setting. The game is studied numerically for different network topologies. Consequences of topology are shown for the wealth time-s

C. Pepin, M. R. Norman

We analyze the fluctuation corrections to magnetic ordering in the case of a 3D antiferromagnet with flat Fermi surfaces, as physically realized in the case of chromium, and find that they are insufficient to produce a quantum critical point. This implies that the critical point observed in vandium doped chromium is due to a loss of nesting. We also derive t

Kestutis Staliunas, Stefano Longhi, German J. de Valcarcel

We show that Faraday patterns can be excited in the weak confinement space of low-dimensional Bose-Einstein condensates by temporal modulation of the trap width, or equivalently of the trap frequency Omega_tight, in the tight confinement space. For slow modulation, as compared with Omega_tight, the low-dimensional dynamics of the condensate in the weak confi

F. Matsubara, T. Shirakura, Y. Baba

We have studied low-lying metastable states of the $\pm J$ Heisenberg model in two ($d=2$) and three ($d=3$) dimensions having developed a hybrid genetic algorithm. We have found a strong evidence of the occurrence of the Parisi states in $d=3$ but not in $d=2$. That is, in $L^d$ lattices, there exist metastable states with a finite excitation energy of $ΔE

Tetsuya Takimoto, Takashi Hotta, Kazuo Ueda

In order to discuss superconductivity in orbital degenerate systems, a microscopic Hamiltonian is introduced. Based on the degenerate model, a strong-coupling theory of superconductivity is developed within the fluctuation exchange (FLEX) approximation where spin and orbital fluctuations, spectra of electron, and superconducting gap function are self-consist

Xin-Qi Li, Wen-Kai Zhang, Ping Cui, Jiushu Shao

Quantum measurement of a solid-state qubit by a mesoscopic detector is of fundamental interest in quantum physics and an essential issue in quantum computing. In this work, by employing a unified quantum master equation approach constructed in our recent publications, we study the measurement-induced relaxation and dephasing of the coupled-quantum-dot states

F Matsubara, T Shirakura, S Endoh, S Takahashi

We reexamine the spin glass (SG) phase transition of the $\pm J$ Heisenberg models with and without the random anisotropy $D$ in three dimensions ($d = 3$) using complementary two methods, i.e., (i) the defect energy method and (ii) the Monte Carlo method. We reveal that the conventional defect energy method is not convincing and propose a new method which c

Richard J. Mathar

Kohn-Sham orbitals of face-centered cubic lithium fluoride are calculated in prototypical local-density approximations to the exchange-correlation functional. The symmetry analysis of these Bloch functions in a LCAO basis on a path Gamma-X-W-K-Gamma-L-W through the Brillouin Zone is compiled into a list of errata to symmetry labels in the LiF literature, the

Makoto Tsubota, Kenichi Kasamatsu, Tsunehiko Araki

In this article, we review the research on the dynamics of quantized vortices in superfluid helium and rotating Bose-Einstein condensates. First, after briefly reviewing the earlier research and describing the current problems on quantized vortices in superfluid $^4$He, we focus our review on superfluid turbulence and vortex filament dynamics. Superfluid tur

Michael N. Leuenberger, Michael E. Flatte, D. D. Awschalom

We propose an experimental method to measure the entanglement of coupled spins, each in a separate quantum dot, by means of multiphoton interference patterns generated through the scattering of two laser beams off the quantum dots. We calculate the N-photon quantum correlations measured by N detectors on an image plane. Using two perpendicular laser beams, e

Rui Carvalho, Alan Penn

We present a broad, phenomenological picture of the distribution of the length of open space linear segments, $l$, derived from maps of 36 cities in 14 different countries. By scaling the Zipf plot of $l$, we obtain two master curves for a sample of cities, which are not a function of city size. We show that a third class of cities is not easily classifiable

M. Rigol, A. Muramatsu, G. G. Batrouni, R. T. Scalettar

Using quantum Monte Carlo simulations, we show that the one-dimensional fermionic Hubbard model in a harmonic potential displays quantum critical behavior at the boundaries of a Mott-insulating region. A local compressibility defined to characterize the Mott-insulating phase has a non-trivial critical exponent. Both the local compressibility and the variance

Abraham Loeb

We show that the time-dependent Doppler effect should induce measureable deviations of the time history of the projected orbit of a star around the supermassive black hole in the Galactic center (SgrA*) from the expected Keplerian history. In particular, the line-of-sight acceleration of the star generates apparent acceleration of its image along its velocit

Edo Berger

The death of massive stars and the processes which govern the formation of compact remnants are not fully understood. Observationally, this problem may be addressed by studying different classes of cosmic explosions and their energy sources. Here we discuss recent results on the energetics of gamma-ray bursts (GRBs) and Type Ib/c Supernovae (SNe Ib/c). In pa

Edo Berger

The association of gamma-ray bursts (GRBs) and core-collapse supernovae (SNe) of Type Ib and Ic was motivated by the detection of SN1998bw in the error box of GRB980425 and the now-secure identification of a SN1998bw-like event in the cosmological GRB030329. The bright radio emission from SN1998bw indicated that it possessed some of the unique attributes exp

Annie C. Mejía, Richard H. Durisen, Megan K. Pickett

Previous simulations of self-gravitating protostellar disks have shown that, once developed, gravitational instabilities are enhanced by cooling the disk constantly during its evolution (Pickett et al. 2002). These earlier calculations included a very simple form of volumetric cooling, with a constant cooling time throughout the disk, which acted against the

Stephen E. Zepf

This paper addresses the questions of what we have learned about how and when dense star clusters form, and what studies of star clusters have revealed about galaxy formation and evolution. One important observation is that globular clusters are observed to form in galaxy mergers and starbursts in the local universe, which both provides constraints on models