March 2002 arXiv papers — page 22

Steven S. Gubser

A brief, example-oriented introduction is given to special holonomy and its uses in string theory and M-theory. We discuss A_k singularities and their resolution; the construction of a K3 surface by resolving T^4/Z_2; holomorphic cycles, calibrations, and worldsheet instantons; aspects of the low-energy effective action for string compactifications; the sign

Z. Chacko, E. Katz, E. Perazzi

We construct a four dimensional realization of a higher dimensional model, Yukawa deflected gauge mediation, in which supersymmetry breaking is communicated to the visible sector through both gauge and Yukawa interactions. The reduction to four dimensions is achieved by `deconstructing' or `latticizing' the extra dimension. Three sites (gauge groups)

Hael Collins, R. Holman, Matthew R. Martin

We explore various facets of the cosmology of the Randall-Sundrum scenario with two branes by considering the dynamics of the branes moving in a bulk AdS/Schwarzschild geometry. This approach allows us both to understand in more detail and from a different perspective the role of the stabilization of the hierarchy in the brane cosmology, as well as to extend

J. D. Jackson

The demonstration that the electromagnetic fields derived from the Lienard-Wiechert potentials do not satisfy the Maxwell equations is proved to be false. Errors were made in the computation of the derivatives of retarded quantities. The subsequent inference of the necessity of both instantaneous and retarded electromagnetic interactions cannot be made. Diff

R. Rajkhowa, J. K. Sarma

We present complete solution of Altarelli-Parisi (AP) evolution equation in next-to-leading order (NLO) and obtain t-evolution of non-singlet structure function at low-x. Results are compared with HERA low-x and low-Q^2 data and also with those of complete solution in leading order (LO) of AP evolution equation.

M. Mueller-Preussker, W. Bietenholz, K. Jansen, F. Jegerlehner

We give here the contents pages for the Proceedings of the Lattice 2001 conference (19th International Symposium on Lattice Field Theory) that took place in August 2001 in Berlin, Germany. The contents are in HTML form with clickable links to the papers that exist on the arXiv, mostly in hep-lat. Corrections and comments should be sent to bunk@physik.hu-berl

Guillermo A. Mena Marugan

The Ashtekar-Barbero formulation of general relativity admits a one-parameter family of canonical transformations that preserves the expressions of the Gauss and diffeomorphism constraints. The loop quantization of the connection formalism based on each of these canonical sets leads to different predictions. This phenomenon is called the Immirzi ambiguity. I

Saulo Carneiro, Guillermo A. Mena Marugan

We present an exact solution of Einstein equations that describes a Bianchi type III spacetime with conformal expansion. The matter content is given by an anisotropic scalar field and two perfect fluids representing dust and isotropic radiation. Based on this solution, we construct a cosmological model that respects the evolution of the scale factor predicte

Ph. Bernard, A. Chincarini, G. Gemme, R. Parodi

Since 1978 superconducting coupled cavities have been proposed as sensitive detector of gravitational waves. The interaction of the gravitational wave with the cavity walls, and the resulting motion, induces the transition of some electromagnetic energy from an initially excited cavity mode to an empty one. The energy transfer is maximum when the frequency o

Yasusada Nambu

We investigate the back reaction of cosmological perturbations on the evolution of the Universe using the renormalization group method. Starting from the second order perturbed Einstein's equation, we renormalize a scale factor of the Universe and derive the evolution equation for the effective scale factor which includes back reaction due to inhomogenei

L. Nunes, E. Oliveira

One of the main questions concerning learning in Multi-Agent Systems is: (How) can agents benefit from mutual interaction during the learning process?. This paper describes the study of an interactive advice-exchange mechanism as a possible way to improve agents' learning performance. The advice-exchange technique, discussed here, uses supervised learnin

K. B. Cooper, M. P. Lilly, J. P. Eisenstein, L. N. Pfeiffer

The recently discovered anisotropy of the longitudinal resistance of two-dimensional electrons near half filling of high Landau levels is found to persist to much higher temperatures T when a large in-plane magnetic field B|| is applied. Under these conditions we find that the longitudinal resistivity scales quasi-linearly with B||/T. These observations supp

C. D. Batista, J. Bonča, J. E. Gubernatis

We introduce a novel mechanism for itinerant ferromagnetism, which is based on a simple two-band model, and using numerical and analytical methods, we show that the Periodic Anderson Model (PAM) contains this mechanism. We propose that the mechanism, which does not assume an intra-atomic Hund's coupling, is present in both the iron group and some $f$ ele

Arun Paramekanti, Leon Balents, Matthew P. A. Fisher

Motivated by the high-T_c cuprates, we consider a model of bosonic Cooper pairs moving on a square lattice via ring exchange. We show that this model offers a natural middle ground between a conventional antiferromagnetic Mott insulator and the fully deconfined fractionalized phase which underlies the spin-charge separation scenario for high-T_c superconduct

J. Ashkenazi

Considering both "large-U" and "small-U" orbitals, it is found that the carriers of the high-Tc cuprates are polaron-like "stripons" carrying charge and located on stripe-like inhomogeneities, "quasi-electrons" carrying charge and spin, and "svivons" carrying spin and lattice distortion. This is shown to result in the

M. V. Yablonskikh, Yu. M. Yarmoshenko, I. V. Solovyev, L. Gridneva

The Mn L_2,L_3 x-ray spectra of the Cu_2MnAl and Co_2MnZ (Z=Al,Ga, Sn, Sb) Heusler alloys have been investigated by the Resonant X-ray Emission Spectroscopy (RXES) using linearly polarized monochromatic synchrotron radiation for. The interplay between the half-metallic character of the Mn 3d electronic structure in connection with the local magnetic moment $

Y. Malevergne, D. Sornette

We investigate the relative information content of six measures of dependence between two random variables $X$ and $Y$ for large or extreme events for several models of interest for financial time series. The six measures of dependence are respectively the linear correlation $ρ^+_v$ and Spearman's rho $ρ_s(v)$ conditioned on signed exceedance of one vari

N. Jakse, J. M. Bomont, J. L. Bretonnet

Large-scale molecular dynamics simulations are performed to predict the structural and thermodynamic properties of liquid krypton using a potential energy function based on the two-body potential of Aziz and Slaman plus the triple-dipole Axilrod-Teller (AT) potential. By varying the strength of the AT potential we study the influence of three-body contributi

N. V. Skorodumova, S. I. Simak

The unusual structural stability of gold nanowires at large separations of gold atoms is explained from first-principles quantum mechanical calculations. We show that undetected light atoms, in particular hydrogen, stabilize the experimentally observed structures, which would be unstable in pure gold wires. The enhanced cohesion is due to the partial charge

B. Derrida, J. L. Lebowitz, E. R. Speer

We obtain the exact probability $\exp[-L {\cal F}(\{ρ(x)\})]$ of finding a macroscopic density profile $ρ(x)$ in the stationary nonequilibrium state of an open driven diffusive system, when the size of the system $L \to \infty$. $\cal F$, which plays the role of a nonequilibrium free energy, has a very different structure from that found in the purely diffus

J. van Mourik, D. Saad, Y. Kabashima

We determine the critical noise level for decoding low density parity check error correcting codes based on the magnetization enumerator ($\cM$), rather than on the weight enumerator ($\cW$) employed in the information theory literature. The interpretation of our method is appealingly simple, and the relation between the different decoding schemes such as ty

Rune Skoe, Damien Vandembroucq, Stephane Roux

Front propagation in a random environment is studied close to the depinning threshold. At zero temperature we show that the depinning force distribution exhibits a universal behavior. This property is used to estimate the velocity of the front at very low temperature. We obtain a Arrhenius behavior with a prefactor depending on the temperature as a power law

Hagen Kleinert

From the path integral formalism for price fluctuations with non-Gaussian distributions I derive the appropriate stochastic calculus replacing Ito's calculus for stochastic fluctuations.

Nic Shannon

We present a concise introduction to a new spinwave expansion scheme for magnetically ordered Kondo lattice models. This is motivated by consideration of the ferromagnetically ordered phase of the "double exchange" system La(1-x)Ca(x)MnO3. A brief overview is given of the consequences of quantum and thermal fluctuation effects for the magnetic proper

Somendra M. Bhattacharjee

The replacment of mutual avoidance of polymers by a long-range interaction of the type proposed by Garel etal (Europhys. Lett. 55, 132 (2001), cond-mat/0101058) is inconsistent with the prevalent renormalization group arguments.

N. Harima, A. Fujimori, T. Sugaya, I. Terasaki

We have studied the chemical potential shift in the high-temperature superconductor Bi$_2$Sr$_2$Ca$_{1-x}${\it R}$_{x}$Cu$_2$O$_{8+y}$ ({\it R} = Pr, Er), where the hole concentration is varied from 0.025 to 0.17 per Cu, by precise measurements of core-level photoemission spectra. The result shows that the shift becomes slow in the underdoped region as in th

P. Esquinazi, A. Setzer, R. Hoehne, C. Semmelhack

We have studied the magnetization of various, well characterized samples of highly oriented pyrolitic graphite (HOPG), Kish graphite and natural graphite to investigate the recently reported ferromagnetic-like signal and its possible relation to ferromagnetic impurities. The magnetization results obtained for HOPG samples for applied fields parallel to the g

P. Ranjith, P. B. Sunil Kumar

We investigate the dynamics of a single semiflexible filament, under the action of a compressing force, using numerical simulations and scaling arguments. The force is applied along the end to end vector at one extremity of the filament, while the other end is held fixed. We find that, unlike in elastic rods the filament folds asymmetrically with a folding l

K. H. Kim, S. Lee, T. W. Noh, S-W. Cheong

Optical spectroscopy was used to investigate the optical gap (2$Δ$) due to charge ordering (CO) and related pseudogap developments with x and temperature (T) in La$_{1-x}$Ca$_{x}$MnO$_{3}$ (0.48 <= x <= 0.67). Surprisingly, we found 2$Δ$/k_{B}T_{CO} is as large as 30 for x ~0.5, and decreases rapidly with increasing x. Simultaneously, the optical pseudogap,

I. V. Ponomarev, A. E. Meyerovich

The effect of random surface roughness on quantum size effect in thin films is discussed. The conductivity of quantized metal films is analyzed for different types of experimentally identified correlation functions of surface inhomogeneities including the Gaussian, exponential, power-law correlators, and the correlators with a power law decay of the power de

O. Vafek, Z. Tesanovic, M. Franz

We show that at long lengthscales and low energies and to leading order in 1/N expansion, the anisotropic QED in 2+1 dimensions renormalizes to an isotropic limit. Consequently, the (Euclidean) relativistic invariance of the theory is spontaneously restored at the isotropic critical point, characterized by the anomalous dimension exponent of the Dirac fermio

Cristina C. Popescu, Richard J. Tuffs

We present results from a new modelling technique which can account for the observed optical/NIR - FIR/submm spectral energy distributions (SEDs) of normal star-forming galaxies in terms of a minimum number of essential parameters specifying the star-formation history and geometrical distribution of stars and dust. The model utilises resolved optical/NIR ima

A. Muench, E. Lada, C. Lada, J. Alves

We use the results of a new, multi-epoch, multi-wavelength, near-infrared census of the Trapezium Cluster in Orion to construct and to analyze the structure of its infrared (K band) luminosity function. Specifically, we employ an improved set of model luminosity functions to derive this cluster&#39;s underlying Initial Mass Function (IMF) across the entire r

Zhehui Wang, Vladimir I. Pariev, Cris W. Barnes, Daniel C. Barnes

A new kind of dynamo utilizing flowing laboratory plasmas has been identified. Conversion of plasma kinetic energy to magnetic energy is verified numerically by kinematic dynamo simulations for magnetic Reynolds numbers above 210. As opposed to intrinsically-turbulent liquid-sodium dynamos, the proposed plasma dynamos correspond to laminar flow topology. Mod

Martin White, J. D. Cohn

This Resource Letter provides a guide to the literature on the theory of anisotropies in the cosmic microwave background. Journal articles, web pages, and books are cited for the following topics: discovery, cosmological origin, early work, recombination, general CMB anisotropy references, primary CMB anisotropies (numerical, analytical work), secondary effe

Eira Kotoneva, Chris Flynn, Raul Jimenez

We present a comparison of the predictions of stellar models with the luminosity of the lower main sequence ($5.5 < M_V < 7.3$) using K dwarfs in the Hipparcos catalog. The parallaxes of our comparison stars are known to better than 15% and metallicities have been recently determined from photometry. A major advantage of our comparison is that distances in o

Uros Seljak

We place limits on the mean density of the universe and the slope of the linear power spectrum around a megaparsec scale by comparing the universal mass function to the observed luminosity function. Numerical simulations suggest that the dark matter halo mass function at small scales depends only on Omega_m(n_eff+3) independent of the overall power spectrum

Robert T. Zavala, Bernard J. McNamara, Thomas E. Harrison, Eduardo Galvan

Years to decade-long cyclic orbital period changes have been observed in several classes of close binary systems including Algols, W Ursae Majoris and RS Canum Venaticorum systems, and the cataclysmic variables. The origin of these changes is unknown, but mass loss, apsidal motion, magnetic activity, and the presence of a third body have all been proposed. I

R. M. Kippen, P. M. Woods, J. Heise, J. J. M. in &#39;t Zand

X-ray flashes (XRFs) are a new type of fast transient source observed with the BeppoSAX Wide Field Cameras (WFC) at a rate of about four per year. Apart from their large fraction of 2-26 keV X-rays, the bulk properties of these events are similar to those of classical gamma-ray bursts (GRBs). By investigating the wide-band spectra of ten events detected in c

Ruth A. Daly, Matthew P. Mory, Erick J. Guerra

There are many different approaches to using observations to constrain or determine the global cosmological parameters that describe our universe. Methods that rely upon a determination of the coordinate distance to high-redshift sources are particularly useful because they do not involve assumptions about the clustering properties of matter, or the evolutio

Silvia Zane, Frank Haberl, Mark Cropper, Vyacheslav E. Zavlin

We present a combined analysis of XMM-Newton, Chandra and Rosat observations of the isolated neutron star RX J0720.4-3125, spanning a total period of \sim 7 years. We develop a maximum likelihood periodogramme based on ΔC statistic and maximum likelihood method, which are appropriate for sparse event lists. As an &#34;a posteriori&#34; check, we have folded

Ortwin Gerhard

This article summarizes recent work on the luminosity and mass distribution of the Galactic bulge and disk, and on the mass of the Milky Way&#39;s dark halo. A new luminosity model consistent with the COBE NIR data and the apparent magnitude distributions of bulge clump giant stars has bulge/bar length of $\simeq 3.5\kpc$, axis ratios of 1:(0.3-0.4):0.3, and

Ortwin Gerhard

The Milky Way has a barred bulge. This article summarizes the current understanding of the main structural parameters and pattern speed of the bar, and compares predicted values for the microlensing optical depth with the bulge microlensing observations.

Ortwin Gerhard

Recent progress in the dynamical analysis of elliptical galaxy kinematics is reviewed. Results reported briefly include (i) the surprisingly uniform anisotropy structure of luminous ellipticals, (ii) their nearly flat (to $\sim 2R_e$) circular velocity curves, (iii) the Tully-Fisher and $M/L - L$ relations and the connection to the Fundamental Plane, and (iv

S. Couvidat, S. Turck-Chieze, A. G. Kosovichev

The SoHO spacecraft made astrophysicists achieve a major breakthrough in the knowledge of the Sun. In helioseismology, both GOLF and MDI experiments aboard SoHO greatly improve the accuracy of seismic data. More specifically, the detection of an enhanced number of low degree low order modes improves the accuracy on the sound speed and density profiles in the

M. A. Voronkov, M. C. Austin, A. M. Sobolev

Using the Haystack Observatory 37-m radio telescope we have undertaken a search for emission in the 2(0)-3(1)E rotational transition of methanol in its first torsionally excited state (v_t=1) at 44.9 GHz. We examined seven galactic sources -- six strong emitters of Class II methanol maser lines and Orion KL, the only source where this line had been previousl

Silvia Zane, Frank Haberl, Mark Cropper, Vyacheslav E. Zavlin

We present a combined analysis of XMM-Newton, Chandra and Rosat observations of the isolated neutron star RXJ0720.4-3125, spanning a total period of \sim 7 years. We develop a maximum likelihood periodogramme for our analysis based on the ΔC-statistic and the maximum likelihood method, which are appropriate for the treatment of sparse event lists. Our result

M. Kappes, J. Pradas, J. Kerp

We present the results of our investigation of the composition of the diffuse soft X-ray background emission (SXRB). Combining data of the Leiden/Dwingeloo HI Survey and the ROSAT All-Sky Survey (RASS), we set up a radiation transport equation in order to model the SXRB. Two different techniques lead to the model parameters: An image oriented approach which

M. Ostrowski, G. Siemieniec-Ozieblo

Accretion flows onto supergalactic-scale structures are accompanied with large spatial scale shock waves. These shocks were postulated as possible sources of ultra-high energy cosmic rays. The highest particle energies were expected for perpendicular shock configuration in the so-called &#34;Jokipii diffusion limit&#34;, involving weakly turbulent conditions

J. Montalban, R. Rebolo

Planet accretion onto solar type stars may significantly change the stellar atmospheric abundances of 6Li and 7Li if it takes place after the star has arrived at the main sequence. Ingestion of planets at an earlier phase will not affect theses abundances because of extensive pre-main sequence mixing and burning. We present quantitative estimates of the main

Antanas Bartkevicius, Arturas Gudas

The results of a kinematical population classification of 497 Hipparcos orbital binaries are discussed. Less than 10% of the stars from the sample belong to the thick disk. Only seven stars have halo kinematics. There are no direct dynamical mass determinations for extreme halo stars. Some suggestions, concerning Population II visual binaries for which groun

Jacques Moret-Bailly

The &#34;Impulsive Stimulated Raman Scattering&#34; (ISRS), is generally performed using ultrashort laser pulses. It shifts the frequency of the laser beam without any change of the wave surfaces and any appearance of extra lines. ISRS works with the pulses which make the usual incoherent light provided that the interactive medium is a low pressure gas havin

P. W. Morris, V. Charmandaris, T. Herter, L. Armus

The SIRTF InfraRed Spectrograph (IRS) is faced with many of the same calibration challenges that were experienced in the ISO SWS calibration program, owing to similar wavelength coverage and overlapping spectral resolutions of the two instruments. Although the IRS is up to ~300 times more sensitive and without moving parts, imposing unique calibration challe

S. C. Chapman, G. F. Lewis, G. Helou

We explore the evolution of the SCUBA sub-mm galaxy population using Monte Carlo simulations to generate synthetic sub-mm/radio color magnitude diagrams. To represent the local distribution of observed dust properties, we use a local far-infrared luminosity function derived from the IRAS 1.2 Jy catalog, bivariate in FIR luminosity and 60micron/100micron colo

Sanjay Reddy, Mariusz Sadzikowski, Motoi Tachibana

We study the weak interaction rates involving Goldstone bosons in the Color Flavor Locked (CFL) quark matter. Neutrino mean free path and the rate of energy loss due to neutrino emission in a thermal plasma of CFL pions and kaons is calculated. We find that in addition to neutrino scattering off thermal mesons, novel Cherenkov like processes wherein mesons a

Ramesh Narayan, Jeremy S. Heyl

Type I X-ray bursts are very common in neutron star X-ray binaries, but no Type I burst has been seen in the dozen or so binaries in which the accreting compact star is too massive to be a neutron star and therefore is identified as a black hole candidate. We have carried out a global linear stability analysis of the accumulating fuel on the surface of a com

M. B. Halpern, N. A. Obers

Recently the operator algebra and twisted vertex operator equations were given for each sector of all WZW orbifolds, and a set of twisted KZ equations for the WZW permutation orbifolds were worked out as a large example. In this companion paper we report two further large examples of this development. In the first example we solve the twisted vertex operator

Prashanth Jaikumar, Madappa Prakash, Thomas Schaefer

We calculate neutrino emissivities from the decay and scattering of Goldstone bosons in the color-flavor-locked (CFL) phase of quarks at high baryon density. Interactions in the CFL phase are described by an effective low-energy theory. For temperatures in the tens of keV range, relevant to the long-term cooling of neutron stars, the emissivities involving G

Motohiro Kemuriyama, Tetsuo Matsui, Kazuhiko Sakakibara

A gauge model of neural network is introduced, which resembles the Z(2) Higgs lattice gauge theory of high-energy physics. It contains a neuron variable $S_x = \pm 1$ on each site $x$ of a 3D lattice and a synaptic-connection variable $J_{xμ} = \pm 1$ on each link $(x,x+\hatμ) (μ=1,2,3)$. The model is regarded as a generalization of the Hopfield model of ass

S. Dawson, S. Heinemeyer

We investigate what can be learned at a linear collider about the sector of electroweak symmetry breaking from a precise measurement of the Higgs boson production cross section through the process e+e- -> hZ. We focus on deviations from the Standard Model arising in its minimal supersymmetric extension. The analysis is performed within two realistic future s

Thierry Baertschiger, Michael Joyce, Francesco Sylos Labini

We analyse with simple real-space statistics the Virgo consortium&#39;s cosmological N-body simulations. Significant clustering rapidly develops well below the initial mean interparticle separation Λ_i, where the gravitational force on a particle is dominated by that with its nearest neighbours. A power-law behaviour in the two point correlation function eme

Kenneth Lane, Kevin R. Lynch, Stephen Mrenna, Elizabeth H. Simmons

Lepton collider experiments can search for light technipions in final states made striking by the presence of an energetic photon: $e+e- \to \photon\technipion$. To date, searches have focused on either production through anomalous coupling of the technipions to electroweak gauge bosons or on production through a technivector meson (\technirho, \techniomega)

Christopher D. Matzner

I constrain a possible supernova origin for gamma-ray bursts by modeling the dynamical interaction between a relativistic jet and a stellar envelope surrounding it. The delay in observer&#39;s time introduced by the jet traversing the envelope should not be long compared to the duration of gamma-ray emission; also, the jet should not be swallowed by a spheri

Andreas U. Schmidt

The dynamical quantum Zeno effect is studied in the context of von Neumann algebras. We identify a localized subalgebra on which the Zeno dynamics acts by automorphisms. The Zeno dynamics coincides with the modular dynamics of that subalgebra, if an additional assumption is satisfied. This relates the modular operator of that subalgebra to the modular operat

Claus Hertling

The base space of a semiuniversal unfolding of a hypersurface singularity carries a rich geometry. By work of K. Saito and M. Saito is can be equipped with the structure of a Frobenius manifold. By work of Cecotti and Vafa it can be equipped with tt* geometry if the singularity is quasihomogeneous. tt* geometry generalizes the notion of variation of Hodge st

Qingjuan Yu, Scott Tremaine

We study the observational constraints on the growth of massive black holes (BHs) in galactic nuclei. We use the velocity dispersions of early-type galaxies obtained by the SDSS and the relation between BH mass and velocity dispersion to estimate the local BH mass density to be 2.5x10^5 Msun/Mpc^3. We also use the QSO luminosity function from the 2dF Redshif

G. M. Bruun, H. Heiselberg

We calculate the elementary excitations and pairing of a trapped atomic Fermi gas in the superfluid phase. The level spectra and pairing gaps undergo several transitions as the strength of the interactions between and the number of atoms are varied. For weak interactions, the Cooper pairs are formed between particles residing in the same harmonic oscillator

A. Bodek, U. K. Yang

We present preliminary results on simple modifications and corrections to GRV94 leading order parton distribution functions such that they can be used to model electron,muon and neutrino deep-inelastic scattering cross sections at low energies.

Z. G. Dai, T. Lu

We generally analyze prompt high-energy emission above a few hundreds of GeV due to synchrotron self-Compton scattering in internal shocks. However, such photons cannot be detected because they may collide with cosmic infrared background photons, leading to electron/positron pair production. Inverse-Compton scattering of the resulting electron/positron pairs

V. N. Gorbachev, A. I. Trubilko, A. A. Rodichkina

Entangled states of the W-class are considered as a quantum channel for teleportation or the states to be sent. The protocols have been found by unitary transformation of the schemes, based on the multiuser GHZ channel. The main feature of the W-quantum channels is a set of non-local operators, that allow receivers recovering unknown state.

Randall D. Kamien

We present an overview of the differential geometry of curves and surfaces using examples from soft matter as illustrations. The presentation requires a background only in vector calculus and is otherwise self-contained.

Amit K. Chattopadhyay, Richard A. Klemm, Debanand Sa

We study analytically the effects of inhomogeneous pairing interactions in short coherence length superconductors, using a spatially varying Bogoliubov-deGennes model. Within the Born approximation, it reproduces all of the standard Abrikosov-Gor&#39;kov pairbreaking and gaplessness effects, even in the absence of actual magnetic impurities. For pairing diso

Harald Ita, Yaron Oz, Tadakatsu Sakai

We study the dynamics of M-theory on G2 holonomy manifolds, and consider in detail the manifolds realized as the quotient of the spin bundle over S^3 by discrete groups. We analyse, in particular, the class of quotients where the triality symmetry is broken. We study the structure of the moduli space, construct its defining equations and show that three diff

Rouzbeh Allahverdi, Anupam Mazumdar, Altug Ozpineci

We discuss some interesting aspects of the $\rm Q$-ball formation during the early oscillations of the flat directions. These oscillations are triggered by the running of soft $({\rm mass})^2$ stemming from the nonzero energy density of the Universe. However, this is quite different from the standard $\rm Q$-ball formation. The running in presence of gauge a

Wung-Hong Huang

The effective potential of quantized scalar field on fuzzy sphere is evaluated to the two-loop level. We see that one-loop potential behaves like that in the commutative sphere and the Coleman-Weinberg mechanism of the radiatively symmetry breaking could be also shown in the fuzzy sphere system. In the two-loop level, we use the heavy-mass approximation and

P. Marecki

We establish a connection between quantum inequalities (known from quantum field theory on curved spacetimes) and the degree of squeezing in quantum-optical experiments. We prove an inequality which binds the reduction of the electric-field fluctuations to their duration. The bigger the level of fluctuations-suppression the shorter its duration. As an exampl

P. Süle

this article has been withdrawn

Dionisio Bazeia

In this work we review some features of topological defects in field theory models for real scalar fields. We investigate topological defects in models involving one and two or more real scalar fields. In models involving a single field we examine two different subclasses of models, which support one or more topological defects. In models involving two or mo

M. H. Dehghani

We consider rotating topological black branes with one rotational parameter in various dimensions. Also a general five-dimensional higher genus solution of the Einstein equation with a negative cosmological constant which represents a topological black brane with two rotational parameters is introduced. We find out that the counterterms inspired by conformal

Justin R. David, Gautam Mandal, Spenta R. Wadia

In this Report we review the microscopic formulation of the five dimensional black hole of type IIB string theory in terms of the D1-D5 brane system. The emphasis here is more on the brane dynamics than on supergravity solutions. We show how the low energy brane dynamics, combined with crucial inputs from AdS/CFT correspondence, leads to a derivation of blac

Alon E. Faraggi, Oscar Vives

The characteristic property of the Z2XZ2 orbifold compactification is the cyclic permutation symmetry between the three twisted sectors. We discuss how this property, which is retained in a class of realistic free fermionic string models, may be instrumental in enabling fermion mass hierarchy while ensuring sfermion mass degeneracy, irrespective of the domin

P. Deuar, P. D. Drummond

P representation techniques, which have been very successful in quantum optics and in other fields, are also useful for general bosonic quantum dynamical many-body calculations such as Bose-Einstein condensation. We introduce a representation called the gauge P representation which greatly widens the range of tractable problems. Our treatment results in an i

John W. Barrett

A set of observables is described for the topological quantum field theory which describes quantum gravity in three space-time dimensions with positive signature and positive cosmological constant. The simplest examples measure the distances between points, giving spectra and probabilities which have a geometrical interpretation. The observables are related

N Bartolo, Andrew R Liddle

We analyze the simplest possible realization of the curvaton scenario, where a nearly scale-invariant spectrum of adiabatic perturbations is generated by conversion of an isocurvature perturbation generated during inflation, rather than the usual inflationary mechanism. We explicitly evaluate all the constraints on the model, under both the assumptions of pr

Yoshiki Hiraoka

We construct some classes of instanton solutions of eight dimensional noncommutative ADHM equations generalizing the solutions of eight dimensional commutative ADHM equations found by Papadopoulos and Teschendorff, and interpret them as supersymmetric $D0$-$D8$ bound states in a NS $B$-field. Especially, we consider the $D0$-$D8$ system with anti-self-dual $

Mikhail Z. Iofa

In heterotic string theory compactified to four dimensions with N=2 supersymmetry, string-loop corrections to the universal sector of the low-energy effective action are studied. Within the framework of N=2 supersymmetric formulation of the theory, in the first order in string coupling constant, we solve the system of the loop-corrected Maxwell and Killing s

Hiroshi Shimahara

An experimental phase diagram of the field-induced superconductivity in the lambda-(BETS)_2FeCl_4 compound is theoretically reproduced by a combination of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state and the Jaccarino-Peter mechanism. Semi-quantitative agreement is obtained in the presence of a very weak subdominant triplet pairing interaction between e

Noriaki Ikeda

We couple three-dimensional Chern-Simons gauge theory with BF theory and study deformations of the theory by means of the antifield BRST formalism. We analyze all possible consistent interaction terms for the action under physical requirements and find a new topological field theory in three dimensions with new nontrivial terms and a nontrivial gauge symmetr

Toyoki Matsuyama, Hideko Nagahiro

A bound state problem in a topologically massive quantum electrodynamics is investigated by using a non-perturbative method. We formulate the Bethe- Salpeter equation for scalar bound states composed of massive fermion and anti-fermion pair under the lowest ladder approximation. In a large mass expansion for the (anti-) fermion, we derive the Schr{ö}dinger e

Alex Buchel

We discuss time-dependent backgrounds of type IIB supergravity realizing gravitation duals of gauge theories formulated in de Sitter space-time as a tool of embedding de Sitter in a supergravity. We show that only the gravitational duals to non-conformal gauge theories are sensitive to a specific value of a Hubble parameter. We consider two nontrivial soluti

Igor V. Volovich

Modern quantum information theory deals with an idealized situation when the spacetime dependence of quantum phenomena is neglected. However the transmission and processing of (quantum) information is a physical process in spacetime. Therefore such basic notions in quantum information theory as qubit, channel, composite systems and entangled states should be

Laurent Chusseau, Jacques Arnaud, Fabrice Philippe

We consider three- and four-level atomic lasers that are either incoherently (unidirectionally) or coherently (bidirectionally) pumped, the single-mode cavity being resonant with the laser transition. The intra-cavity Fano factor and the photo-current spectral density are evaluated on the basis of rate equations. According to that approach, fluctuations are

S. Guerin, R. Unanyan, L. P. Yatsenko, H. R. Jauslin

Preparation of entangled pairs of coupled two-state systems driven by a bichromatic external field is studied. We use a system of two coupled spin-1/2 that can be translated into a three-state ladder model whose intermediate state represents the entangled state. We show that this entangled state can be prepared in a robust way with appropriate fields. Their

Quentin Thommen, Veronique Zehnle, Jean Claude Garreau

We study the dynamics of a wavepacket in a potential formed by the sum of a periodic lattice and of a parabolic potential. The dynamics of the wavepacket is essentially a superposition of ``local Bloch oscillations&#39;&#39;, whose frequency is proportional to the local slope of the parabolic potential. We show that the amplitude and the phase of the Fourier

M. Caselle, F. Di Cunto, P. Provero

Gene regulation in eukaryotes is mainly effected through transcription factors binding to rather short recognition motifs generally located upstream of the coding region. We present a novel computational method to identify regulatory elements in the upstream region of eukaryotic genes. The genes are grouped in sets sharing an overrepresented short motif in t

Michael Meyer-Hermann

A general criterion is formulated in order to decide if recycling of B-cells exists in GC reactions. The criterion is independent of the selection and affinity maturation process and based solely on total centroblast population arguments. An experimental test is proposed to verify whether the criterion is fulfilled.

Jeremy S. Heyl

A simple variation of the traditional Young&#39;s double slit experiment can demonstrate several subtleties of interference with polarized light, including Berry and Pancharatnam&#39;s phase. Since the position of the fringes depends on the polarization state of the light at the input, the apparatus can also be used to measure the light&#39;s polarization wi

Bing He, Hu Li, Qing Sun, C. M. Shakin

The Nambu--Jona-Lasinio (NJL) model has been extensively studied by many researchers. In previous work we have generalized the NJL model to include a covariant model of confinement. In the present work we consider further modification of the model so as to reproduce the type of Euclidean-space momentum- dependent quark mass values obtained in lattice simulat

K. Weibert, J. Main, G. Wunner

In the periodic orbit quantization of physical systems, usually only the leading-order hbar contribution to the density of states is considered. Therefore, by construction, the eigenvalues following from semiclassical trace formulae generally agree with the exact quantum ones only to lowest order of hbar. In different theoretical work the trace formulae have

Christian Maes, Evgeny Verbitskiy

We consider expansive homeomorphisms with the specification property. We give a new simple proof of a large deviation principle for Gibbs measures corresponding to a regular potential and we establish a general symmetry of the rate function for the large deviations of the antisymmetric part, under time-reversal, of the potential. This generalizes the Gallavo