December 2001 arXiv papers
Showing 1–100 of 2,706 papers
Masaru Siino
The generic crease set of an event horizon possesses anisotropic structure though most of black holes are dynamically stable. This fact suggests that a generic almost spherical black hole has a very crumpled crease set in a microscopic scale though the crease set is similar to a point-wise crease set in a macroscopic scale. In the present article, we count t
P. M. Hajac, R. Matthes, W. Szymanski
The irreducible *-representations of the polynomial algebra O(S^3_{pq}) of the quantum 3-sphere introduced by Calow and Matthes are classified. The K-groups of its universal C*-algebra are shown to coincide with their classical counterparts. The U(1)-action on O(S^3_{pq}) corresponding for p=1=q to the classical Hopf fibration is proven to be Galois (free).
Je-An Gu, W-Y. P. Hwang
In this paper we propose that the accelerating expansion of the present matter-dominated universe, as suggested by the recent distance measurements of type Ia supernovae, is generated along with the evolution of space in extra dimensions. The Einstein equations are first analyzed qualitatively and then solved numerically, so as to exhibit explicitly these pa
Micha Berkooz, Amit Sever, Assaf Shomer
Double-trace deformations of the AdS/CFT duality result in a new perturbation expansion for string theory, based on a non-local worldsheet. We discuss some aspects of the deformation in the low energy gravity approximation, where it appears as a change in the boundary condition of fields. We relate unique features of the boundary of AdS to the worldsheet bec
Enhancement of long-range magnetic order by magnetic field in superconducting La2CuO(4+y)
cond-mat.supr-conB. Khaykovich, Y. S. Lee, R. Erwin, S. -H. Lee
We report a detailed study, using neutron scattering, transport and magnetization measurements, of the interplay between superconducting (SC) and spin density wave (SDW) order in La2CuO(4+y). Both kinds of order set in below the same critical temperature. However, the SDW order grows with applied magnetic field, whereas SC order is suppressed. Most important
R. J. Furnstahl
Bulk nuclear observables such as charge radii and binding energies are well described by both nonrelativistic and covariant mean-field models. However, predictions of neutron radii, which are not tightly constrained by reliable data, vary significantly. The nature of this variation is investigated using correlations between basic properties of the models and
Carl Mueller, Roger Tribe
We consider Funaki's model of a random string taking values in R^d. It is specified by the following stochastic PDE, du = u_{xx} + W, where W=W(x,t) is two-parameter white noise, also taking values in R^d. We study hitting properties, double points, and recurrence. The main difficulty is that the process has the Markov property in time, but not in space.
Naveen Surendran, R. Shankar
We construct Heisenberg anti-ferromagnetic models in arbitrary dimensions that have isotropic valence bond crystals (VBC) as their exact ground states. The d=2 model is the Shastry-Sutherland model. In the 3-d case we show that it is possible to have a lattice structure, analogous to that of SrCu_2(BO_3)_2, where the stronger bonds are associated with shorte
F. A. Dolan, H. Osborn
Superconformal transformations are derived for the $\N=2,4 supermultiplets corresponding to the simplest chiral primary operators. These are applied to two, three and four point correlation functions. When $\N=4$, results are obtained for the three point function of various descendant operators, including the energy momentum tensor and SU(4) current. For bot
Ming-Hsien Tu, Niann-Chern Lee, Yu-Tung Chen
A covariant approach to the conformal property associated with Moyal-Lax operators is given. By identifying the conformal covariance with the second Gelfand-Dickey flow, we covariantize Moyal-Lax operators to construct the primary fields of one-parameter deformation of classical $W$-algebras.
V. R. Zoller
We study coherent Coulomb excitation of ultrarelativistic nuclei passing through the aligned crystal target. We develop multiple scattering theory description of this process which consistently incorporates both the specific resonant properties of particle-crystal interactions and the shadowing effect typical of the diffractive scattering. We emphasise that
A. Porzio, C. Altucci, P. Aniello, C. de Lisio
Twin beam fluctuations are analyzed for detuned and mismatched OPO configurations. Resonances and frequency responses to the quantum noise sources (quantum and pump amplitude/phase fluctuations) are examined as functions of cavity decay rates, excitation parameter and detuning. The dependence of self- and mutual correlations of beam amplitudes and phases on
Dafang Zheng, G. J. Rodgers, P. M. Hui
We present a generalization of the dynamical model of information transmission and herd behavior proposed by Eguiluz and Zimmermann. A characteristic size of group of agents $s_{0}$ is introduced. The fragmentation and coagulation rates of groups of agents are assumed to depend on the size of the group. We present results of numerical simulations and mean fi
J. Bec, R. Iturriaga, K. Khanin
The dynamics of the multi-dimensional randomly forced Burgers equation is studied in the limit of vanishing viscosity. It is shown both theoretically and numerically that the shocks have a universal global structure which is determined by the topology of the configuration space. This structure is shown to be particularly rigid for the case of periodic bounda
Kondo effect and anti-ferromagnetic correlation in transport through tunneling-coupled double quantum dots
cond-mat.mes-hallBing Dong, X. L. Lei
We propose to study the transport through tunneling-coupled double quantum dots (DQDs) connected in series to leads, using the finite-$U$ slave-boson mean field approach developed initially by Kotliar and Ruckenstein [Phys. Rev. Lett. {\bf 57}, 1362 (1986)]. This approach treats the dot-lead coupling and the inter-dot tunnelling $t$ nonperturbatively at arbi
R. P. Malik
We discuss some aspects of the topological features of a non-interacting two (1+1)-dimensional Abelian gauge theory in the framework of superfield formalism. This theory is described by a BRST invariant Lagrangian density in the Feynman gauge. We express the local and continuous symmetries, Lagrangian density, topological invariants and symmetric energy mome
Rong-Gen Cai
We continue the study of thermodynamics of black holes in de Sitter spaces. In a previous paper (hep-th/0111093), we have shown that the entropy of cosmological horizon in the Schwarzschild-de Sitter solution and topological de Sitter solution can be expressed in a form of the Cardy-Verlinde formula, if one adopts the prescription to compute the gravitationa
Osamu Iguchi
Many self-gravitating systems often show scaling properties in their mass density, system size, velocities and so on. In order to clarify the origin of these scaling properties, we consider the stationary state of N-body system with inverse power law interaction. As a simple case, we consider the self-similar stationary solution in the collisionless Boltzman
Colin Benjamin, A. M. Jayannavar
The subject of time in quantum mechanics is of perennial interest especially because there is no observable for the time taken by a particle to transmit (or reflect) from a particular region. Several methods have been proposed based on scattering phase shifts and using different quantum clocks, where the time taken is clocked by some external input or indire
Masanao Ozawa
Conservation laws limit the accuracy of physical implementations of elementary quantum logic gates. If the computational basis is represented by a component of spin and physical implementations obey the angular momentum conservation law, any physically realizable unitary operators with size less than n qubits cannot implement the controlled-NOT gate within t
T. Harada, C. Goymer, B. J. Carr
In cosmological models with a varying gravitational constant, it is not clear whether primordial black holes preserve the value of $G$ at their formation epoch. We investigate this question by using the Tolman-Bondi model to study the evolution of a background scalar field when a black hole forms from the collapse of dust in a flat Friedmann universe. Provid
Bohdan Grzadkowski, Zenro Hioki
Angular distribution of the secondary lepton in top-quark production followed by subsequent semi-leptonic decay is studied assuming general top-quark couplings. It is shown that the distribution does not depend on any possible anomalous tbW couplings and is determined only by the standard V-A decay vertex for any production mechanism if certain well-justifie
M. S. Hussein, A. F. R. de Toledo Piza, O. K. Vorov, A. K. Kerman
Using the information on the nuclear structure of exotic neutron-rich halo nucleus $^{11}$Be, we evaluate the parity violating anapole moment in its ground state. The resulting value $κ(^{11}$Be)$=0.17$ is fifteen times bigger than the typical value of the anapole moment of a normal nucleus of the same mass, and in fact exceeds by few times anapole moments o
Sean Gavin, Joseph I. Kapusta
Enhancement of omega and antiomega baryon production in Pb+Pb collisions at a c.m. energy of 17 A GeV can be explained by the formation of many small disoriented chiral condensate regions. This explanation implies that neutral and charged kaons as well as pions must exhibit novel isospin fluctuations. We compute the distribution of the fraction of neutral pi
H. F. Chau, F. K. Chow
What is the physical origin of player cooperation in minority game? And how to obtain maximum global wealth in minority game? We answer the above questions by studying a variant of minority game from which players choose among $N_c$ alternatives according to strategies picked from a restricted set of strategy space. Our numerical experiment concludes that pl
Oleg Shvedov
Semiclassical systems being symmetric under Lie group are studied. A state of a semiclassical system may be viewed as a set (X,f) of a classical state X and a quantum state f in the external classical background X. Therefore, the set of all semiclassical states may be considered as a bundle ("semiclassical bundle"). Its base {X} is the set of all cla
Ilya Kapovich
We prove that for a finitely generated subgroup $H$ of a word-hyperbolic group $G$ the Frattini subgroup $F(H)$ of $H$ is finite.
Alexandru Nica, Dimitri Shlyakhtenko, Roland Speicher
Let $M$ be a $B$-probability space. Assume that $B$ itself is a $D$-probability space; then $M$ can be viewed as $D$-probability space as well. Let $X$ be in $M$. We look at the question of relating the properties of $X$ as $B$-valued random variable to its properties as $D$-valued random variable. We characterize freeness of $X$ from $B$ with amalgamation o
Boris Okun
We construct a tangential map from a locally symmetric space of noncompact type to its dual compact type twin. By comparing the induced map in cohomology to a map defined by Matsushima, we conclude that in the equal rank case the map has a nonzero degree.
Juan Gonzalez-Meneses
We give presentations, in terms of generators and relations, for the monoids of singular braids on closed surfaces. The proof of the validity of these presentations can also be applied to verify, in a new way, the presentations given by Birman for the monoids of Singular Artin braids.
Felix Schlenk
We extend the ``Extension after Restriction Principle'' for symplectic embeddings of bounded starlike domains to a large class of symplectic embeddings of unbounded starlike domains.
Gonzalo Comas, Malena Seiguer
We describe in the space of binary forms of degree d the strata of forms having constant rank. We also give a simple algorithm to determine the rank of a given form.
O. Lemmers, J. Wiegerinck
Let V be a bounded pseudoconvex Reinhardt domain in C^2 with many strictly pseudoconvex points and logarithmic image W. It was known that the maximal ideal in $H^{\infty}(V)$ consisting of all functions vanishing at (p,q) in V is generated by the coordinate functions z-p, w-q (meaning that one can solve the Gleason problem for $H^{\infty}(V)$) if W is bounde
Louis H. Kauffman, David E. Radford
This paper discusses the construction of a generalized Alexander polynomial for virtual knots and links, and the reformulation of this invariant as a quantum link invariant. The algebraic background for the generalized Alexander module is formulated in terms of the biquandle, a generalization of the quandle of David Joyce (which, in turn, is a generalization
Pierre Ramond
Nature's attraction to unique mathematical structures provides powerful hints for unraveling her mysteries. None is at present as intriguing as eleven-dimensional M-theory. The search for exceptional structures specific to eleven dimensions leads us to exceptional groups in the description of space-time. One specific connection, through the coset $F_4/SO
Huan-Xiong Yang
Based on the twisted R-R tadpole cancellation conditions at the singularities of D=4 Type IIB orbifold $T^6/ Z_3$, we propose a new bottom-up approach to embed standard model with three generations into string theory.
Utpal Chattopadhyay, Achille Corsetti, Pran Nath
An analysis of supersymmetric dark matter under the Yukawa unification constraint is given. The analysis utilizes the recently discovered region of the parameter space of models with gaugino mass nonuniversalities where large negative supersymmetric corrections to the b quark mass appear to allow $b-τ$ unification for a positive $μ$ sign consistent with the
D. Blaschke, G. Burau, Yu. Kalinovsky, T. Barnes
We investigate the in-medium modification of the charmonium breakup processes due to the Mott effect for light (pi, rho) and open-charm (D, D*) quark-antiquark bound states at the chiral/deconfinement phase transition. The Mott effect for the D-mesons effectively reduces the threshold for charmonium breakup cross sections, which is suggested as an explanatio
Hogan Nguyen
I present several preliminary measurements from KTeV of the fundamental neutral kaon parameters, and their implications for CPT violation. A new limit is given on the sidereal time dependence of $ϕ_{+-}$. The results are based on data collected in 1996-97.
B. Aubert
The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of 23 million $\B\bar B$ pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to t
B. Aubert
Flavor oscillations of neutral $B$ mesons have been studied in $e^+e^-$ annihilation data collected with the BABAR detector at center-of-mass energies near the $Υ(4S)$ resonance. The data sample used for this purpose consists of events in which one $B^0$ meson is reconstructed in a hadronic decay mode, while the flavor of the recoiling $B^0$ is determined wi
Gerald Eigen
The performance of present multipurpose detectors at high luminosities is discussed.
Gerald Eigen
Based on background measurements at PEP II the impact of machine-related backgrounds on individual components of multipurpose detectors is examined, that operate in an asymmetric B factory at luminosities up to 10^{36} cm^{-2} s^{-1}. Extrapolations of the BABAR experience suggests two feasible detector designs.
G. Eigen
Radiative penguin decays provide a hunting ground complementary to direct searches for physics beyond the Standard Model. In the era of B-factories copious production of B mesons permits precision measurements of radiative penguin decays. We present herein the status of radiative penguin processes and expectations at high luminosities, focusing on b -> s (d)
Post-Newtonian gravitational radiation and equations of motion via direct integration of the relaxed Einstein equations. II. Two-body equations of motion to second post-Newtonian order, and radiation-reaction to 3.5 post-Newtonian order
gr-qcMichael E. Pati, Clifford M. Will
We derive the equations of motion for binary systems of compact bodies in the post-Newtonian (PN) approximation to general relativity. Results are given through 2PN order (order (v/c)^4 beyond Newtonian theory), and for gravitational radiation reaction effects at 2.5PN and 3.5PN orders. The method is based on a framework for direct integration of the relaxed
Yuri N. Obukhov
We discuss some aspects of the gravitational interaction of the relativistic quantum particles with spin 1/2. The exact Foldy-Wouthuysen transformation is constructed for the Dirac particle coupled to the static spacetime metric. The quasi-relativistic limit of the theory is then analyzed. Using the analogous method, we obtain the exact Cini-Touschek transfo
L. B. Ioffe, A. J. Millis
The effect of proximity to a Mott insulating phase on the charge transport properties of a superconductor is determined. An action describing the low energy physics is formulated and different scenarios for the approach to the Mott phase are distinguished by different variation with doping of the parameters in the action. A crucial issue is found to be the d
A. J. Millis
This is the text of the 'Theory' opening talk at the 2001 Strongly Correlated Electron Systems conference. It contains opinions about some of the outstanding scientific challenges facing the theory side of the correlated electrons field.
Correlation studies of open and closed states fluctuations in an ion channel: Analysis of ion current through a large conductance locust potassium channel
cond-matZuzanna Siwy, Marcel Ausloos, Kristinka Ivanova
Ion current fluctuations occurring within open and closed states of large conductance locust potassium channel (BK channel) were investigated for the existence of correlation. Both time series, extracted from the ion current signal, were studied by the autocorrelation function (AFA) and the detrended fluctuation analysis (DFA) methods. The persistent charact
C. Schönenberger, S. Oberholzer, E. V. Sukhorukov, H. Grabert
In these notes we discuss the origin of shot noise ('Schroteffekt') of vacuum tubes in detail. It will be shown that shot noise observed in vacuum tubes and first described by W. Schottky in 1918 is a purely classical phenomenon. This is in pronounced contrast to shot noise investigated in mesoscopic conductors which is due to quantum mechanical diff
Herd Formation and Information Transmission in a Population: Non-universal behaviour
cond-mat.stat-mechDafang Zheng, P. M. Hui, K. F. Yip, N. F. Johnson
We present generalized dynamical models describing the sharing of information, and the corresponding herd behavior, in a population based on the recent model proposed by Egu\'ıluz and Zimmermann (EZ) [Phys. Rev. Lett. 85, 5659 (2000)]. The EZ model, which is a dynamical version of the herd formation model of Cont and Bouchaud (CB), gives a reasonable mod
From Linear to Nonlinear Response in Spin Glasses: Importance of Mean-Field-Theory Predictions
cond-mat.dis-nnV. S. Zotev, R. Orbach
Deviations from spin-glass linear response in a single crystal Cu:Mn 1.5 at % are studied for a wide range of changes in magnetic field, $ΔH$. Three quantities, the difference $TRM-(MFC-ZFC)$, the effective waiting time, $t_{w}^{eff}$, and the difference $TRM(t_{w})-TRM(t_{w}=0)$ are examined in our analysis. Three regimes of spin-glass behavior are observed
C. Goldenberg, I. Goldhirsch
It has been claimed that quasistatic granular materials, as well as nanoscale materials, exhibit departures from elasticity even at small loadings. It is demonstrated, using 2D and 3D models with interparticle harmonic interactions, that such departures are expected at small scales [below O(100) particle diameters], at which continuum elasticity is invalid,
Quasiequilibrium sequences of synchronously rotating binary neutron stars with constant rest masses in general relativity -- Another approach without using the conformally flat condition --
astro-phFumihiko Usui, Yoshiharu Eriguchi
We have computed quasiequilibrium sequences of synchronously rotating compact binary star systems with constant rest masses. This computation has been carried out by using the numerical scheme which is different from the scheme based on the conformally flat assumption about the space. Stars are assumed to be polytropes with polytropic indices of N=0.5, N=1.0
Luigi Danese, Gian Luigi Granato, Laura Silva, Manuela Magliocchetti
In view of the extensive evidence of a tight inter-relationship between spheroidal galaxies (and galactic bulges) and massive black holes hosted at their centers, a consistent model must deal jointly with the evolution of the two components. We describe one viable model, which successfully accounts for the local luminosity function of spheroidal galaxies, th
Time-Dependent, Multifluid, Magnetohydrodynamic Shock Waves with Grain Dynamics I. Formulation and Numerical Tests
astro-phGlenn E. Ciolek, Wayne G. Roberge
This is the first in a series of papers on the effects of dust on the formation, propagation, and structure of nonlinear MHD waves and MHD shocks in weakly-ionized plasmas. We model the plasma as a system of 9 interacting fluids, consisting of the neutral gas, ions, electrons, and 6 grain fluids comprised of very small grains or PAHs and classical grains in
P. M. Wallace, J. P. Halpern, A. M. Magalhaes, D. J. Thompson
We present a multiwavelength analysis of the high-energy gamma-ray source 3EG J2006-2321. The flux of this source above 100 MeV is shown to be variable on time scales of days and months. Optical observations and careful examination of archived radio data indicate that its radio counterpart is PMN J2005-2310, a flat-spectrum radio quasar with a 5-GHz flux den
First XMM-Newton observations of strongly magnetic cataclysmic variables - II. Timing studies of DP Leo and WW Hor
astro-phDirk Pandel, France A. Cordova, Robert E. Shirey, Gavin Ramsay
XMM-Newton was used to observe two eclipsing, magnetic cataclysmic variables, DP Leo and WW Hor, continuously for three orbital cycles each. Both systems were in an intermediate state of accretion. For WW Hor we also obtained optical light curves with the XMM-Newton Optical Monitor and from ground-based observations. Our analysis of the X-ray and optical lig
Frank C. van den Bosch
We present detailed, analytical models for the formation of disc galaxies to investigate the impact that cooling and feedback have on their structural properties. In particular, we investigate which observables extracted directly from the models are best suited as virial mass estimators, and to what extent they allow the recovery of the model input parameter
Y. M. Cho
We establish a non-Abelian superconductivity and a non-Abelian Meissner effect by constructing an effective field theory of superconductivity in which a genuine SU(2) gauge symmetry governs the dynamics. We show that the magnetic flux is quantized in the unit of $4π/g$, not $2π/g$, in the non-Abelian superconductor.
Shengjun Wu, Jeeva Anandan
We present three necessary separability criteria for bipartite mixed states, the violation of each of these conditions is a sufficient condition for entanglement. Some ideas on the issue of finding a necessary and sufficient criterion of separability are also discussed.
A. Del Sol Mesa, C. Quesne
In a recent paper (Del Sol Mesa A and Quesne C 2000 J. Phys. A: Math. Gen. 33 4059), we started a systematic study of the connections among different factorization types, suggested by Infeld and Hull, and of their consequences for the construction of algebras. We devised a general procedure for constructing satellite algebras for all the Hamiltonians admitti
Nonlocality of nucleon interaction and an anomalous off shell behavior of the two-nucleon amplitudes
nucl-thRenat Kh. Gainutdinov, Aigul A. Mutygullina
The problem of the ultraviolet divergences that arise in describing the nucleon dynamics at low energies is considered. By using the example of an exactly solvable model it is shown that after renormalization the interaction generating nucleon dynamics is nonlocal in time. Effects of such nonlocality on low-energy nucleon dynamics are investigated. It is sho
Daniel J. H. Chung, Thomas Dent
We study a new baryogenesis scenario in a class of braneworld models with low fundamental scale, which typically have difficulty with baryogenesis. The scenario is characterized by its minimal nature: the field content is that of the Standard Model and all interactions consistent with the gauge symmetry are admitted. Baryon number is violated via a dimension
A. Kageyama, S. Kaneko, N. Shimoyama, M. Tanimoto
We investigate the lepton flavor violation in the framework of the MSSM with right-handed neutrinos taking the large mixing angle MSW solution in the quasi-degenerate and the inverse-hierarchical neutrino masses. We predict the branching ratio of $μ\to e+γ$ and $τ\to μ+γ$ processes assuming the degenerate right-handed Majorana neutrino masses. We find that t
Experimental realization of Shor's quantum factoring algorithm using nuclear magnetic resonance
quant-phLieven M. K. Vandersypen, Matthias Steffen, Gregory Breyta, Costantino S. Yannoni
The number of steps any classical computer requires in order to find the prime factors of an $l$-digit integer $N$ increases exponentially with $l$, at least using algorithms known at present. Factoring large integers is therefore conjectured to be intractable classically, an observation underlying the security of widely used cryptographic codes. Quantum com
San-Ru Hao, Lu-Ya Wang
In this paper, we have proposed a q-deformed Jaynes-Cummings(JC) model and constructed the q-SuperCoherent States(q-SCSs) for the q-deformed JC model. We have also discussed the properties of the q-supercoherent states and given the completeness relation expression. The representation of the q-supercoherent states for the q-deformed JC model is studied as we
B. G. Sidharth
Inaba recently used a simple model to suggest that Quantum Theory can result from a fluctuation in the cosmos. In this note we confirm this conclusion from a different and more general point of view. We then argue that this provides an explanation for the recently observed variation of the fine structure constant.
V. F. Dmitriev, R. A. Sen'kov
Hyperfine splitting in Bi$^{82+}$ and Pb$^{81+}$ ions was calculated using continuum RPA approach with effective residual forces. To fix the parameters of the theory the nuclear magnetic dipole moments of two one- particle and two one-hole nuclei around $^{208}$Pb were calculated using the same approach. The contribution from velocity dependent two-body spin
Vladimir V. Kisil
We combine the coordinate method and Erlangen program in the framework of noncommutative geometry through an investigation of symmetries of noncommutative coordinate algebras. As the model we use the coherent states construction and the wavelet transform in functional spaces. New examples are a three dimensional spectrum of a non-normal matrix and a quantisa
Partha Sarathi Chakraborty
Compact quantum metric spaces are order unit spaces along with a Lip norm. On the order unit space of the selfadjoint elements of the dense subalgebra of smooth elements in the quantum Heisenberg manifold we construct Lip norms.
Takao Koikawa
We study the features of the vacuum of the harmonic oscillator in the Moyal quantization. Two vacua are defined, one with the normal ordering and the other with the Weyl ordering. Their equivalence is shown by using a differential equation satisfied by the normal ordered vacuum.
Tianjun Li
We study the principles of the gauge symmetry and supersymmetry breaking due to the local or global discrete symmetries on the extra space manifold. We show that the gauge symmetry breaking by Wilson line is the special case of the discrete symmetry approach where all the discrete symmetries are global and act freely on the extra space manifold. As applicati
Sergiu I. Vacaru, Evghenii Gaburov
We consider exact solutions of Einstein equations defining static black holes parametrized by off-diagonal metrics which by anholonomic mappings can be equivalently transformed into some diagonal metrics with coefficients being very similar to those from the Schwarzschild and/or Reissner-Nördstrom solutions with anisotropic renormalizations of constants. We
Helio V. Fagundes
In this talk work done by our group on cosmic topology is reviewed. It ranges from early attempts to solve a famous controversy about quasars through the multiplicity of images, to quantum cosmology in this context and an application to QED renormalization.
Candida Ferreira
Gene expression programming, a genotype/phenotype genetic algorithm (linear and ramified), is presented here for the first time as a new technique for the creation of computer programs. Gene expression programming uses character linear chromosomes composed of genes structurally organized in a head and a tail. The chromosomes function as a genome and are subj
Yi-Kuo Yu, Yi-Cheng Zhang
We provide the probability distribution function of matrix elements each of which is the inner product of two vectors. The vectors we are considering here are independently distributed but not necessarily Gaussian variables. When the number of components M of each vector is greater than the number of vectors N, one has a $N\times N$ symmetric matrix. When $M
Direct observation of the phonon energy in a Bose-Einstein condensate by tomographic imaging
cond-mat.softRoee Ozeri, Jeff Steinhauer, Nadav Katz, Nir Davidson
The momentum and energy of phonons in a Bose-Einstein condensate are measured directly from a time-of-flight image by computerized tomography. We find that the same atoms that carry the momentum of the excitation also carry the excitation energy. The measured energy is in agreement with the Bogoliubov spectrum. Hydrodynamic simulations are performed which co
Study of the Ce(Rh$_{1-x}$Pd$_x$)$_2$Si$_2$ alloy: evidence for itinerant character of the magnetic order in CeRh$_2$Si$_2$
cond-mat.str-elM. Gomez Berisso, P. Pedrazzini, J. G. Sereni, O. Trovarelli
We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh$_{1-x}$Pd$_x$)$_2$Si$_2$ system and compare the results with those obtained at intermediate and low Rh concentrations. The analysis of the x-evolution of the entropy and the scaling behaviour of $C_{el}(T)$ and $ρ(T)$ clearly confi
Adham Hashibon, Joan Adler, Michael W. Finnis, Wayne D. Kaplan
In an earlier report we explored structural correlations at a liquid-solid interface with molecular dynamics simulations of a model aluminium system using the Ercolessi-Adams potential and up to 4320 atoms. Substrate atoms were pinned to their equilibrium fcc crystalline positions while liquid atoms were free to move. A direct correlation between the amount
Adham Hashibon, Joan Adler, Michael W. Finnis, Wayne D. Kaplan
Structural correlations at a liquid-solid interface were explored with molecular dynamics simulations of a model aluminium system using the Ercolessi-Adams potential and up to 4320 atoms. Substrate atoms were pinned to their equilibrium crystalline positions while liquid atoms were free to move. The density profile at the interface was investigated for diffe
S. B. Popov
In this paper we briefly review our recent results on evolution and properties of isolated neutron stars (INSs) in the Galaxy. As the first step we discuss stochastic period evolution of INSs. We briefly discuss how an INS's spin period evolves under influence of interaction with turbulized interstellar medium. To investigate statistical properties of th
A. Treves, S. B. Popov, M. Colpi, M. E. Prokhorov
We model Galactic populations of accreting and cooling isolated neutron stars in the attempt to explore their link with a new class of dim soft X-ray sources revealed by ROSAT. For accretors we follow the magneto-rotational and dynamical evolution in the Galactic potential and a realistic large scale distribution of the interstellar medium is used. Under sta
Condensed vortex ground states of rotating Bose-Einstein condensate in harmonic atomic trap
cond-mat.stat-mechM. S. Hussein, O. K. Vorov
We study a system of $N$ Bose atoms trapped by a symmetric harmonic potential, interacting via weak central forces. Considering the ground state of the rotating system as a function of the two conserved quantities, the total angular momentum and its collective component, we develop an algebraic approach to derive exact wave functions and energies of these gr
Vitor Cardoso, Jose' P. S. Lemos
We study the collision between a BTZ black hole and a test particle coupled to a scalar field. We compute the power spectrum, the energy radiated and the plunging waveforms for this process. We show that for late times the signal is dominated by the quasinormal ringing. In terms of the AdS/CFT correspondence the bulk gravity process maps into a thermal state
Semiclassical Quantization for the Spherically Symmetric Systems under an Aharonov-Bohm magnetic flux
quant-phW. F. Kao, P. G. Luan, D. H. Lin
The semiclassical quantization rule is derived for a system with a spherically symmetric potential $V(r) \sim r^ν$ $(-2<ν<\infty)$ and an Aharonov-Bohm magnetic flux. Numerical results are presented and compared with known results for models with $ν= -1,0,2,\infty$. It is shown that the results provided by our method are in good agreement with previous resul
Dynamical evolution of clusters of galaxies: the effect of high- velocity substructure clumps
astro-phA. Del Popolo, M. Gambera, E. N. Ercan
In the Cold Dark Matter (hereafter CDM) scenario even isolated density peaks contain a high fraction of small scale clumps having velocities larger than the average escape velocity from the structure. These clumps populate protoclusters, especially in the peripheral regions, r > R_f (where R_f is the filtering scale). During the cluster collapse and the subs
Carsten Greiner
This talk is devoted to review the field of strangeness production in (ultra-)relativistic heavy ion collisions within our present theoretical understanding. Historically there have been (at least) three major ideas for the interest in the production of strange hadronic particles: (1) mass modification of the kaons in a (baryon-)dense environment; (2) (early
The van der Waals Potential between Metastable Atoms and Solid Surfaces: Novel Diffraction Experiments versus Theory
quant-phRuediger Bruehl, Peter Fouquet, Robert E. Grisenti, J. Peter Toennies
Highly polarizable metastable He* ($\mathrm{2^3S}$) and Ne* ($\mathrm{2^3P}$) atoms have been diffracted from a 100 nm period silicon nitride transmission grating and the van der Waals coefficients $C_3$ for the interaction of the excited atoms with the silicon nitride surface have been determined from the diffraction intensities out to the 10th order. The r
C. G. Tsagas, P. K. S. Dunsby, M. Marklund
We discuss how gravitational waves could amplify seed magnetic fields to strengths capable of supporting the galactic dynamo. We consider the interaction of a weak magnetic field with gravity wave distortions in almost FRW cosmologies and find that the magnitude of the original field is amplified proportionally to the wave induced shear anisotropy and, cruci
Determination of the axial coupling constant $g_{A}$ in the linear representations of chiral symmetry
hep-phA. Hosaka, D. Jido, M. Oka
If a baryon field belongs to a certain linear representation of chiral symmetry of $SU(2) \otimes SU(2)$, the axial coupling constant $g_{A}$ can be determined algebraically from the commutation relations derived from the superconvergence property of pion-nucleon scattering amplitudes. This establishes an algebraic explanation for the values of $g_{A}$ of su
R. Srikanth
Einstein-Podolsky-Rosen- (EPR) and the more powerful Mayers-Lo-Chau attack impose a serious constraint on quantum bit commitment (QBC). As a way to circumvent them, it is proposed that the quantum system encoding the commitment chosen by the committer (Alice) should be initially prepared in a seperable quantum state known to and furnished by the acceptor (Bo
Shin-itiro Goto, Kazuhiro Nozaki, Hiroyasu Yamada
We present a method to construct a symplecticity preserving renormalization group map of a chain of weakly nonlinear symplectic maps and obtain a general reduced symplectic map describing its long-time behaviour. It is found that the modulational instability in the reduced map triggers random wandering of orbits around some homoclinic-like manifolds, which i
David N. Yetter
The analogy between Yetter's deformation theory form (lax) monoidal functors and Gerstenahaber's deformation theory for associative algebras is solidified by shown that under reasonable conditions the category of functors with an action of a lax monoidal functor is abelian, that an analogue of the Hochschild cohomology of an algebra with coefficients
Dmitri Zaitsev, Giuseppe Zampieri
Given a wedge V with generic edge in a submanifold M of $C^N$, in general, CR-functions on V do not extend to a wedge in $C^N$ in the direction of each nontrivial value of the Levi form of M as was recently observed by Eastwood and Graham. In this paper we propose an invariant geometric way of selecting those Levi form directions that are responsible for the
Hilmar Forkel
Nonperturbative Wilson coefficients associated with the leading chiral-symmetry-breaking operators in the operator product expansion of the pseudoscalar QCD correlation function are derived. Implementation of the new, instanton-induced operators enables the corresponding spectral sum rule to reproduce the small pion mass scale, thereby reconciling it with Go
Damped $\sin(β-α)$ of Higgs couplings and the lightest Higgs production at $γγ$ colliders in MSSM
hep-phChao-Shang Huang, Xiao-Hong Wu
In the decoupling limit, $M^2_{A^0} \gg M^2_Z$, the heavy CP-even, CP-odd and charged Higgs boson masses are nearly degenerate, $\sin(β-α)$ approaches 1, and the lightest CP-even Higgs boson almost displays the same properties as the Standard Model Higgs boson. But the stop and sbottom sector can change this pattern through radiative corrections. We find tha
Y. Hosotani, T. Nakajima, R. G. Daghigh, J. I. Kapusta
When a potential for a scalar field has two local minima there arise spherical shell-type solutions of the classical field equations due to gravitational attraction. We establish such solutions numerically in a space which is asymptotically de Sitter. It generically arises when the energy scale characterizing the scalar field potential is much less than the
Christos G Tsagas
We discuss how the vector nature of magnetic fields, and the geometrical interpretation of gravity introduced by general relativity, lead to a special coupling between magnetism and spacetime curvature. This magneto-geometrical interaction effectively transfers the tension properties of the field into the spacetime fabric, triggering a variety of effects wit
Robert D. Klauber
An intriguing, and possibly significant, anomalous signal in the Brillet and Hall experiment is contrasted with a simple first order test of special relativity subsequently performed to discount that signal as spurious. Analysis of the non-time-orthogonal nature of the rotating earth frame leads to the conclusion that the latter test needed second order accu