January 2004 arXiv papers — page 15

Semyon Alesker

A new method of constructing translation invariant continuous valuations on convex subsets of the quaternionic space $\HH^n$ is presented. In particular new examples of $Sp(n)Sp(1)$-invariant translation invariant continuous valuations are constructed. This method is based on the theory of plurisubharmonic functions of quaternionic variables.

Asoka Biswas, G. S. Agarwal

We present a scheme to realise the basic two-quibit logic gates such as quantum phase gate and controlle-NOT gate using a detuned optical cavity interacting with a three-level Raman system. We discuss the role of Stark shifts which are as important as the terms leading to two-photon transition. The operation of the proposed logic gates involves metastable st

David Delphenich

The basic physical problems that necessitated the emergence of quantum physics are summarized, along with the elements of wave mechanics and its traditional statistical interpretation. Alternative interpretations to the statistical one, such as the hydrodynamical and optical interpretations, nonlinear waves and nonlinear electrodynamics, and the conception o

Shaun N Mosley

We present a new set of massless Poincaré group operators Hermitian with respect to the $ 1 / r $ inner product space, which have quasi-plane wave energy-momentum eigenfunctions having velocity $ c $ along their axis of propagation. These are constructed by means of a unitary transformation from a known set of massless Poincaré group operators of helicity $

D. Angom, S. Ghosh, V. K. B. Kota

We revisit statistical wavefunction properties of finite systems of interacting fermions in the light of strength functions and their participation ratio and information entropy. For weakly interacting fermions in a mean-field with random two-body interactions of increasing strength $λ$, the strength functions $F_k(E)$ are well known to change, in the regime

D. Porras, J. I. Cirac

We show that the physical system consisting of trapped ions interacting with lasers may undergo a rich variety of quantum phase transitions. By changing the laser intensities and polarizations the dynamics of the internal states of the ions can be controlled, in such a way that an Ising or Heisenberg-like interaction is induced between effective spins. Our s

Akihisa Tomita, Kazuo Nakamura

Quantum Fourier transform (QFT) is a key function to realize quantum computers. A QFT followed by measurement was demonstrated on a simple circuit based on fiber-optics. The QFT was shown to be robust against imperfections in the rotation gate. Error probability was estimated to be 0.01 per qubit, which corresponded to error-free operation on 100 qubits. The

Barbara Drossel, Alan McKane, Christopher Quince

We investigate the long-term web structure emerging in evolutionary food web models when different types of functional responses are used. We find that large and complex webs with several trophic layers arise only if the population dynamics is such that it allows predators to focus on their best prey species. This can be achieved using modified Lotka-Volterr

Morten Kloster, Chao Tang, Ned Wingreen

The use of gene microchips has enabled a rapid accumulation of gene-expression data. One of the major challenges of analyzing this data is the diversity, in both size and signal strength, of the various modules in the gene regulatory networks of organisms. Based on the Iterative Signature Algorithm [Bergmann, S., Ihmels, J. and Barkai, N. (2002) Phys. Rev. E

G. Sardin

Within the framework of test-experiments, an original pointing set-up based on speed-induced deflection of a light-beam and using a high-resolution opto-electronic array as a position detector, is proposed. The device would provide a new way to ratify the first order optical equivalency of inertial systems and to sound its causal groundwork. The type of test

G. Sardin

A dual optical set-up is proposed to detect simultaneously the different behavior of light from stellar and local sources, in relation to speed-induced aberration. A small laser is set at the center of the objective lens of a telescope, allowing to record at once the two spots on an array detector. Their positions are recorded during a yearly earth orbit, so

David D. Reid, William B. Klann, J. M. Wadehra

Using a complex model potential, we have calculated the total, integrated elastic, momentum transfer, absorption, and differential cross sections for positrons scattered from molecular hydrogen. The widely available software package GAUSSIAN is used to generate the radial electronic charge density of the molecule which is used to produce the interaction pote

C. Biscari

In the post-LEP era the high energy frontier is reachable only by large scale collaborations and laboratories, while the present lepton colliders operating at low and intermediate energies are planning major upgrades aimed at increasing substantially their luminosity, in order to meet the continuous interest in precision physics. The lowest energies are now

A. K. Mohanty

The high $P_T$ trigger capabilities of the ALICE inner tracking system (ITS) as a standalone detector have been investigated. Since the high $P_T$ charged particles mostly lead to the linear trajectories within this ITS sector, it is possible to select tracks of $P_T$ of the order of 2 GeV and above by confining to a narrow search window in the ($θ,ϕ$) space

A. S. Sandhu, S. Sengupta, A. Das, A. K. Dharmadhikari

We report experimental evidence of electrostatic inhibition of fast electrons, generated in a highly resistive material upon irradiation with an intense ultra-short ($10^{16} W/cm^{2}$, $100 fmsec$) laser pulse. The experiment involves measurement of temporal evolution of self-generated magnetic pulses using pump-probe polarimetry. A comparison is made betwe

T. Zelevinsky

This paper has been temporarily withdrawn. Highly nonlinear dependences of 4He 2^3S - 2^3P lines on pressure were observed in vapor cell saturation spectroscopy. Line shifts agree with those expected from light-pressure-induced perturbation of atomic velocity distribution. In the lin-perp-lin pump and probe polarization configuration, multilevel atomic struc

T. Zelevinsky

This paper has been temporarily withdrawn by the authors. In the process of 4He 2P fine structure measurement in a vapor cell, highly nonlinear dependences of 2S_1 - 2P_J intervals on helium density are observed and attributed to light pressure. If total angular momentum of the excited state is not greater than that of the ground state, there are large polar

Yuri A. Rylov

One can construct the model conception of quantum phenomena (MCQP) which relates to the axiomatic conception of quantum phenomena (ACQP), (i.e. to the conventional quantum mechanics) in the same way, as the statistical physics relates to thermodynamics. Such a possibility is based on a new conception of geometry, which admits one to construct such a determin

P. Kowina, H. -H. Adam, A. Budzanowski, R. Czyzykiewicz

Measurements of the near threshold Lambda and Sigma0 production via the pp-->pK+Lambda/Sigma0 reaction at COSY--11 have shown that the Lambda/Sigma0 cross section ratio exceeds the value at high excess energies Q>=300 MeV by an order of magnitude. For a better understanding additional data have been taken between 13 MeV and 60 MeV excess energy. Within the f

Andrey Tsiganov

An integrable deformation of the known integrable model of two interacting p-dimensional and q-dimensional spherical tops is considered. After reduction this system gives rise to the generalized Lagrange and the Kowalevski tops. The corresponding Lax matrices and classical r-matrices are calculated.

Peter B. Weichman

It was recently demonstrated [P. B. Weichman, Phys. Rev. Lett. {\bf 91}, 143908 (2003)] that the scattered electric field from highly conducting targets following a rapidly terminated electromagnetic pulse displays a universal $t^{-1/2}$ power law divergence at early time. It is now shown that for strongly permeable targets, $μ_c/μ_b \gg 1$, where $μ_b$ is t

Natig M. Atakishiyev, Anatoliy U. Klimyk, Kurt Bernardo Wolf

The finite q-oscillator is a model that obeys the dynamics of the harmonic oscillator, with the operators of position, momentum and Hamiltonian being functions of elements of the q-algebra su_q(2). The spectrum of position in this discrete system, in a fixed representation j, consists of 2j+1 "sensor"-points x_s=(1/2)[2s]_q, s=-j, -j+1,..., j, and si

David B. Fairlie

Further investigations of implicit solutions to non-linear partial differential equations are pursued. Of particular interest are the equations which are Lorentz invariant. The question of which differential equations of second order for a single unknown $ϕ$ are solved by the imposition of an inhomogeneous quadratic relationship among the independent variabl

Bozhidar Z. Iliev

An analog of the classical Doppler effect is investigated in spaces (manifolds) whose tangent bundle is endowed with a transport along paths, which, in particular, can be parallel one. The obtained results are valid irrespectively to the particles mass, i.e. they hold for massless particles (e.g. photons) as well as for massive ones.

Albert Fannjiang, Knut Solna

We prove the convergence of the solutions of the parabolic wave equation to that of the Gaussian white-noise model widely used in the physical literature. The random medium is isotropic and is assumed to have integrable correlation coefficient in the propagation direction. We discuss the limits of vanishing inner scale and divergent outer scale of the turbul

Cindy De Volder, Antonio Laface

Consider a (non-empty) linear system of surfaces of degree d in P^3 through at most 8 multiple points in general position and let L denote the corresponding complete linear system on the blowing-up X of P^3 along those general points. Then we determine the base locus of such linear systems L on X.

Huaxin Lin

Let $A$ be a unital separable amenable \CA and $C$ be a unital \CA with certain infinite property. We show that two full monomorphisms $h_1, h_2: A\to C$ are approximately unitarily equivalent if and only if $[h_1]=[h_2]$ in $KL(A,C).$ Let $B$ be a non-unital but $σ$-unital \CA for which $M(B)/B$ has the certain infinite property. We prove that two full esse

Huaxin Lin

Let $A$ be an amenable separable \CA and $B$ be a non-unital but $σ$-unital simple \CA with continuous scale. We show that two essential extensions $τ_1$ and $τ_2$ of $A$ by $B$ are approximately unitarily equivalent if and only if $$ [τ_1]=[τ_2] {\rm in} KL(A, M(B)/B). $$ If $A$ is assumed to satisfy the Universal Coefficient Theorem, there is a bijection f

Tim Boykett, Peter Mayr

We present a construction method of BIB-designs from a finite group G and a group of automorphisms Φon G such that |Φ(x)| = |Φ| for all x in G, x <> 0. By using a generalization of the concept of a difference family we can so unify several previous constructions of BIB-designs from planar near-rings.

Habiba Kadiri

The Riemann Zeta function $ζ(s)$ never vanishes in the region : $$ \Re s \ge 1- \frac1{5.70176 \log |\Im s|} \quad \quad (|\Im s| \ge 2). $$

Frederic Chapoton

Some enumerative aspects of the fans, called generalized associahedra, introduced by S. Fomin and A. Zelevinsky in their theory of cluster algebras are considered, in relation with a bicomplex and its two spectral sequences. A precise enumerative relation with the lattices of generalized noncrossing partitions is conjectured and some evidence is given.

Wolfgang Bertram, Karl-Hermann Neeb

We define symmetric spaces in arbitrary dimension and over arbitrary non-discrete topological fields $\K$, and we construct manifolds and symmetric spaces associated to topological continuous quasi-inverse Jordan pairs and -triple systems. This class of spaces, called smooth generalized projective geometries, generalizes the well-known (finite or infinite-di

Ilse Fischer

We compute the generating function of column-strict plane partitions with parts in {1,2,...,n}, at most c columns, p rows of odd length and k parts equal to n. This refines both, Krattenthaler&#39;s [&#34;The major counting of nonintersecting lattice paths and generating functions for tableaux&#34;, Mem. Amer. Math. Soc. 115 (1995)] and the author&#39;s [&#3

Herbert Koch, Daniel Tataru

The aim of these notes is to describe some recent results concerning dispersive estimates for principally normal pseudodifferential operators. The main motivation for this comes from unique continuation problems. Such estimates can be used to prove Carleman inequalities, which in turn yield unique continuation results for various partial differential operato

Endre Csáki, Antónia Földes, Pál Révész

Strong theorems are given for the maximal local time on balls and subspaces for the $d$-dimensional simple symmetric random walk.

Jan-Hendrik Evertse, Umberto Zannier

Let k be an algebraically closed field of characteristic 0, let K/k be a transcendental extension of arbitrary transcendence degree and let G be a multiplicative subgroup of (K^*)^n such that (k^*)^n is contained in G, and G/(k^*)^n has finite rank r. We consider linear equations a1x1+...+anxn=1 (*) with fixed non-zero coefficients a1,...,an from K, and with

Hiroshi Yamauchi

In this article we prove that the full automorphism group of the baby-monster vertex operator superalgebra constructed by Hoehn is isomorphic to 2xB, where B is the baby-monster sporadic finite simple group and determine irreducible modules for the baby-monster vertex operator algebra. Our result has many corollaries. In particular, we can prove that the Z_2

Jan Snellman, Michael Paulsen

An integer partition λof n corresponds, via its Ferrers diagram, to an artinian monomial ideal I of colength n in the polynomial ring on two variables. If the partition λcorresponds to an integrally closed ideal we call λconcave. We study generating functions for the number of concave partitions, unrestricted or with at most r parts.

V. Tarasov, A. Varchenko

Given complex numbers $m_1,l_1$ and positive integers $m_2,l_2$, such that $m_1+m_2=l_1+l_2$, we define $l_2$-dimensional hypergeometric integrals $I_{a,b}(z;m_1,m_2,l_1,l_2)$, $a,b=0,...,\min(m_2,l_2)$, depending on a complex parameter $z$. We show that $I_{a,b}(z;m_1,m_2,l_1,l_2)=I_{a,b}(z;l_1,l_2,m_1,m_2)$, thus establishing an equality of $l_2$ and $m_2$

Stephan Mohrdieck, Robert Wendt

We show that untwisted respectively twisted conjugacy classes of a compact and simply connected Lie group which satisfy a certain integrality condition correspond naturally to irreducible highest weight representations of the corresponding affine Lie algebra. Along the way, review the classification of twisted conjugacy classes of a simply connected compact

Hiroshi Yamauchi

In this article, using an idea of the physics superselection principal, we study a modularity on vertex operator algebras arising from semisimple primary vectors. We generalizes the theta functions on vertex operator algebras and prove that the internal automorphisms do not change the genus one twisted conformal blocks.

Megumi Harada, Nicholas J. Proudfoot

We consider a manifold X obtained by a Kahler reduction of C^n, and we define its hyperkahler analogue M as a hyperkahler reduction of T^*C^n = H^n by the same group. In the case where the group is abelian and X is a smooth toric variety, M is a toric hyperkahler manifold, as defined by Bielawski-Dancer, and further studied by Konno and Hausel-Sturmfels. The

V. Tarasov, A. Varchenko

We consider the Knizhnik-Zamolodchikov (KZ) and dynamical equations, both differential and difference, in the context of the (gl_k,gl_n) duality. We show that the KZ and dynamical equations naturally exchange under the duality.

A. Rebhan, P. van Nieuwenhuizen, R. Wimmer

We discuss new insights into the quantum physics of solitons developed since 1997: why quantum corrections to the mass M and the central charge Z of solitons in supersymmetric (susy) field theories in 1+1 and 2+1 dimensions are nonvanishing, despite the fact that the zero-point energies of bosons and fermions seem to cancel each other, and the central charge

Guido Cognola, Sergio Zerbini

The one-loop effective action for a scalar field defined in the ultrastatic space-time where non standard logarithmic terms in the asymptotic heat-kernel expansion are present, is investigated by a generalisation of zeta-function regularisation. It is shown that additional divergences may appear at one-loop level. The one-loop renormalisability of the model

Pietro Fre&#39;, Leonardo Modesto

In the previous submission of this paper we claimed to have solved the problem of constructing a consistent non-abelian Born Infeld action which is $κ$--supersymmetric to all orders. Our method was based on an extension of target superspace to $\mathrm{N} \times \mathrm{N}$ matrix--valued objects for all the items appearing in the geometric construction. The

Christian van Enckevort

We describe mirror symmetry on higher dimensional tori, paying special attention to the behaviour of D-branes under mirror symmetry. To find the mirror D-branes the description of mirror symmetry on D-branes due to Ooguri, Oz en Yin is used. This method allows us to deal with the coisotropic D-branes recently introduced by Kapustin and Orlov. We compare this

Arjun Berera

Warm inflationary dynamics is shown to satisfy both the slow-roll and density perturbation constraints for $m_ϕ \gg H$ or equivalently $η\gg 1$ and for inflaton field amplitudes much below the Planck scale, $<ϕ> < m_{pl}$. I start by reviewing the two types of inflation dynamics, isentropic or cold inflation and nonisentropic or warm inflation. In the former

F. Schrempp, A. Utermann

We report on the interesting possibility of instanton-driven gluon saturation in lepton-nucleon scattering at small Bjorken-x. Our results crucially involve non-perturbative information from high-quality lattice simulations. The conspicuous, intrinsic instanton size scale < rho > ~ 0.5 fm, as known from the lattice, turns out to determine the saturation scal

M. A. Tortola

We use solar neutrino data to derive stringent bounds on Majorana neutrino transition moments (TMs). Such moments, if present, would contribute to the neutrino-electron scattering cross section and hence alter the signal observed in Super-Kamiokande. Using the latest solar neutrino data, combined with the results of the reactor experiment KamLAND, we perform

O. C. Anoka, K. S. Babu, I. Gogoladze

We suggest and analyze a class of supersymmetric Z&#39; models based on the gauge symmetry U(1)_x = x Y - (B-L), where Y is the Standard Model hypercharge. For 1 < x < 2, the U(1)_x D-term generates positive contributions to the slepton masses, which is shown to solve the tachyonic slepton problem of anomaly mediated supersymmetry breaking (AMSB). The result

S. Berge, P. Nadolsky, F. Olness, C. -P. Yuan

Analysis of small-x semi-inclusive DIS hadroproduction suggests that multiple parton radiation leads to a broadening of transverse momentum distributions beyond that predicted by a straightforward calculation in the Collins-Soper-Sterman formalism. This effect can be modeled by a modification of the resummed form factor in the small-x region. We discuss the

S. M. Zebarjad, M. Haghighat

We derive Spinless Salpeter equation for the positronium using the NRQED Lagrangian. Consequently, we consider the Spinless Salpeter wavefunction instead of the Schrodinger wavefunction to show that the NRQED calculation can be done easier. We also discuss that the singularity of the Spinless Salpeter wavefunction at the origin is necessary to cancel the ult

P. Perez, A. Rosowsky

We describe a novel design for an intense source of slow positrons based on pair production with a beam of electrons from a 10 MeV accelerator hitting a thin target at a low incidence angle. The positrons are collected with a set of coils adapted to the large production angle. The collection system is designed to inject the positrons in a Greaves-Surko trap

R. Aloisio, P. Blasi, A. Galante, A. F. Grillo

Quantum gravitational effects may induce stochastic fluctuations in the structure of space-time, to produce a characteristic foamy structure. It has been known for some time now that these fluctuations may have observable consequences for the propagation of cosmic ray particles over cosmological distances. While invoked as a possible explanation for the dete

M. Sharif

We consider radiation-dominated Friedmann universe and evaluate its force four-vector and momentum. We analyse and compare the results with the already evaluated for the matter-dominated Friedmann model. It turns out that the results are physically acceptable.

M. Sharif, T. Iqbal

We investigate solutions of Einstein field equations for the non-static spherically symmetric perfect fluid case using different equations of state. The properties of an exact spherically symmetric perfect fluid solutions are obtained which contain shear. We obtain three different solutions out of these one turns out to be an incoherent dust solution and the

A. T. Bollinger, A. Rogachev, M. Remeika, A. Bezryadin

We study the effect of morphology on the low temperature behavior of superconducting nanowires of length $\approx$100 nm. A well-defined superconductor-insulator transition (SIT) is observed only in homogenous wires, in which case the transition occurs when the normal resistance is close to $h/4e^2$. Inhomogeneous wires, on the other hand, exhibit a mixed be

V. M. Apalkov, M. E. Raikh, B. Shapiro

Motivated by recent experiments on intensity correlations of the waves transmitted through disordered media, we demonstrate that the speckle pattern from disordered photonic crystal with incomplete band-gap represents a sensitive tool for determination the stop-band width. We establish the quantitative relation between this width and the {\em angualar anisot

J. Takahashi, A. Suisalu, An. Kuznetsov, A. Laisaar

Irreversible broadening of spectral holes in chlorin-doped polystyrene glass was studied for the first time in the temperature cycling experiments under high pressure (by raising the temperature from 5 K to various magnitudes up to 18 K and turning back to 5 K at several fixed pressures between 0 and 5 kbar). At all pressures the increment in the hole width

X. F. Wang

We study ballistic transport of spin-polarized electrons through quantum wires in which the strength of the Rashba spin-orbit interaction (SOI) is spatially modulated. Subband mixing, due to SOI, between the two lowest subbands is taken into account. Simplified approximate expressions for the transmission are obtained for electron energies close to the botto

Julia S. Meyer, Alex Kamenev, Leonid I. Glazman

We study charge transport in a granular array with high inter-grain conductances. We show that the system exhibits a Berezinskii-Kosterlitz-Thouless crossover from the high-temperature conducting state into a low-temperature insulating state. The crossover takes place at a critical temperature T_{BKT} \propto E_c exp{-g}, where E_c is the charging energy of

M. R. Evans

Systems driven out of equilibrium can often exhibit behaviour not seen in systems in thermal equilibrium- for example phase transitions in one-dimensional systems. In this talk I will review several `condensation&#39; transitions that occur when a conserved quantity is driven through the system. Although the condensation is spatial, i.e. a finite fraction of

A. E. Koshelev, A. A. Golubov

It is well established that the superconductivity in the recently discovered superconducting compound MgB$_{2}$ resides in the quasi-two-dimensional band ($σ$-band) and three-dimensional band ($π$-band). We demonstrate that, due to such band structure, the anisotropic Ginzburg-Landau theory practically does not have region of applicability, because gradient

W. K. Theumann, R. Erichsen

The dynamics and the stationary states of an exactly solvable three-state layered feed-forward neural network model with asymmetric synaptic connections, finite dilution and low pattern activity are studied in extension of a recent work on a recurrent network. Detailed phase diagrams are obtained for the stationary states and for the time evolution of the re

V. Ya. Pokrovskii, A. V. Golovnya, S. V. Zaitsev-Zotov

We propose a model of the Peierls transition (PT) taking into account amplitude fluctuations of the charge-density waves and spontaneous thermally activated suppression of the Peierls gap, akin to the phase slip process. The activation results in the exponential growth of the normal phase with increasing temperature. The model fairly describes the behavior o

A. Yu. Emelyanov

General energy approaches have been applied to study the single-domain polarization reversal induced by the voltage-modulated Atomic Force Microscopy (AFM) in ferroelectric single crystals and thin films. Topographic analysis of energy surfaces in the subspace of domain dimensions is performed, and energy evolutions under an external bias are elucidated. Thi

I. V. Bondarev, Ph. Lambin

We report a strictly non-exponential spontaneous decay dynamics of an excited two-level atom placed inside or at different distances outside a carbon nanotube (CN). This is the result of strong non-Markovian memory effects arising from the rapid variation of the photonic density of states with frequency near the CN. The system exhibits vacuum-field Rabi osci

P. Capuzzi, A. Minguzzi, M. P. Tosi

We study the collective modes of a confined gaseous cloud of bosons and fermions with mutual attractive interactions at zero temperature. The cloud consists of a Bose-Einstein condensate and a spin-polarized Fermi gas inside a spherical harmonic trap and the coupling between the two species is varied by increasing either the magnitude of the interspecies s-w

Bernd Rosenow, Rafael Weissbach, Frank Altrock

The risk of a credit portfolio depends crucially on correlations between the probability of default (PD) in different economic sectors. Often, PD correlations have to be estimated from relatively short time series of default rates, and the resulting estimation error hinders the detection of a signal. We present statistical evidence that PD correlations are w

S. A. Trigger, G. J. F. van Heijst, P. P. J. M. Schram

A self-consistent and universal description of friction and diffusion for Brownian particles (grains) in different systems, as a gas with Boltzmann collisions, dusty plasma with ion absorption by grains, and for active particles (e.g., cells in biological systems) is suggested on the basis of the appropriate Fokker-Planck equation. Restrictions for applicati

W. Desrat, F. Giazotto, V. Pellegrini, F. Beltram

We report magneto-transport measurements on high-mobility two-dimensional electron systems (2DESs) confined in In_0.75Ga_0.25As/In_0.75Al_0.25As single quantum wells. Several quantum Hall states are observed in a wide range of temperatures and electron densities, the latter controlled by a gate voltage down to values of 1.10^11 cm^-2. A tilted-field configur

O. Sørensen

A description of a large system of particles is often sought in a derivation from the detailed behaviour of just a few of the particles. The present thesis deals with the connection between such microscopic features and the nature of a collection of many particles. The study of two-body correlations yields insight into mechanisms that in the dilute limit can

D. Brockmann, L. Hufnagel

We investigate front propagation in a reacting particle system in which particles perform scale-free random walks known as Levy flights. The system is described by a fractional generalization of a reaction-diffusion equation. We focus on the effects of fluctuations caused by a finite number of particles. We show that, inspite of superdiffusive particle dispe

A. R. Akbarzadeh, L. Bellaiche, Kevin Leung, Jorge Íñiguez

A parameterized effective Hamiltonian approach is used to investigate KTaO$_3$. We find that the experimentally observed anomalous dielectric response of this incipient ferroelectric is well reproduced by this approach, once quantum effects are accounted for. Quantum fluctuations suppress the paraelectric--to--ferroelectric phase transition; it is unnecessar

F. Ritort

In this report I discuss fluctuation theorems and transient violations of the second law of thermodynamics in small systems. Special emphasis is placed on free-energy recovery methods in the framework of non-equilibrium single-molecule pulling experiments. The treatment is done from a unified theoretical-experimental perspective and emphasizes how these expe

Su-Huai Wei, Pierre Carrier

Using a band-structure method that includes the correction to the band gap error in the local density approximation (LDA), we study the chemical trends of the band gap variation in III-V semiconductors and predict that the band gap for InN is 0.8 +/- 0.1 eV, which is much smaller than previous experimental value of approx. 1.9 eV. The unusually small band ga

Eddy Ardonne, Paul Fendley, Eduardo Fradkin

We discuss a certain class of two-dimensional quantum systems which exhibit conventional order and topological order, as well as two-dimensional quantum critical points separating these phases. All of the ground-state equal-time correlators of these theories are equal to correlation functions of a local two-dimensional classical model. The critical points th

J. Rho, S. Ramirez, M. F. Corcoran, K. Hamaguchi

The Trifid Nebula, a young star-forming HII region, was observed for 16 hours by the Chandra X-ray Observatory. We detected 304 X-ray sources, thirty percent of which are hard sources and seventy percent of of which have near-infrared counterparts. Chandra resolved the HD164492 multiple system into a number of discrete X-ray sources. X-ray emission is detect

Marina M. Romanova, Galina V. Ustyugova, Alexander V. Koldoba, Justin V. Wick

We present results of fully three-dimensional MHD simulations of disk accretion to a rotating magnetized star with its dipole moment inclined at an angle Theta to the rotation axis of the disk. We observed that matter accretes from the disk to a star in two or several streams depending on Theta. Streams may precess around the star at small Theta. The inner r

Alice C. Quillen, David E. Trilling, Eric G. Blackman

We numerically investigate the possibility that a close stellar encounter could account for the high inclinations of the Kuiper belt, as originally proposed by Ida, Larwood and Burkert, however we consider encounters with pericenters within those explored by previous works. A star of mass 0.2 Msol entering the solar system on a nearly parabolic, low inclinat

G. S. Bisnovatyi-Kogan

After some historical remarks we discuss different criteria of dynamical stability of stars, and properties of the critical states where dynamical stability is lost, leading to collapse with formation of the neutron star or a black hole. At the end some observational and theoretical problems related to quark stars are discussed.

S. B. Foulkes, C. A. Haswell, J. R. Murray, D. J. Rolfe

Two dimensional SPH simulations of a precessing accretion disc in a q=0.1 binary system (such as XTE J1118+480) reveal complex and continuously varying shape, kinematics, and dissipation. The stream-disc impact region and disc spiral density waves are prominent sources of energy dissipation.The dissipated energy is modulated on the period P_{sh} = ({P_{orb}}

G. S. Bisnovatyi-Kogan

The present common view about GRB origin is related to cosmology, what is based on statistical analysis, and on measurements of the redshifts in the GRB optical afterglows of long GRB. No correlation is found between redshifts, GRB spectrum, and total GRB fluence. Comparison of KONUS and BATSE data about statistics and hard X-ray lines is done, and some diff

H. J. Voelk, V. N. Zirakashvili

Cosmic ray acceleration by shocks related with Slipping Interaction Regions (SIRs) in the Galactic Wind is considered. SIRs are similar to Solar Wind Corotating Interaction Regions. The spiral structure of our Galaxy results in a strong nonuniformity of the Galactic Wind flow and in SIR formation at distances of 50 to 100 kpc. SIRs are not corotating with th

T. Sanchis, G. A. Mamon, E. Salvador-Sole&#39;, J. M. Solanes

The origin of the deficiency in neutral Hydrogen of 13 spiral galaxies lying in the outskirts of the Virgo cluster is reassessed. If these galaxies have passed through the core of the cluster, their interstellar gas should have been lost through ram pressure stripping by the hot X-ray emitting gas of the cluster. We analyze the positions of these HI-deficien

Michael J. West, Patrick Cote, Ronald O. Marzke, Andres Jordan

Nearly a century after the true nature of galaxies as distant &#34;island universes&#34; was established, their origin and evolution remain great unsolved problems of modern astrophysics. One of the most promising ways to investigate galaxy formation is to study the ubiquitous globular star clusters that surround most galaxies. Recent advances in our underst

Martin J. Rees

Collapsed objects have definitely been observed: some are stellar-mass objects, the endpoint of massive stars; others, millions of times more massive, have been discovered in the cores of most galaxies. Their formation poses some still-unanswered questions. But for relativists the key question is whether observations can probe the metric in the strong-field

Debra Meloy Elmegreen, Bruce G. Elmegreen, Clara M. Sheets

Colors and magnitudes were determined for 69 chain galaxies, 58 other linear structures, 32 normal edge-on galaxies, and all of their large star formation clumps in the HST ACS field of the Tadpole galaxy. Redshifts of 0.5 to 2 are inferred from comparisons with published color-evolution models. The linear galaxies have no red nuclear bulges like the normal

J. D. Monnier, R. Millan-Gabet, P. G. Tuthill, W. A. Traub

We present first results of an experiment to combine data from Keck aperture masking and the Infrared-Optical Telescope Array (IOTA) to image the circumstellar environments of evolved stars with ~20 milliarcsecond resolution. The unique combination of excellent Fourier coverage at short baselines and high-quality long-baseline fringe data allows us to determ

Olaf Wucknitz, Ulrich Sperhake

Various authors have investigated the problem of light deflection by radially moving gravitational lenses - with inconsistent results. In this paper we generalize the calculations for arbitrary lens velocities and show that, to first order in the lens velocity v, the deflection angles scales with 1-v. We discuss the seeming inconsistency of relativistic ligh

L. Origlia, P. Ranalli, A. Comastri, R. Maiolino

The near infrared (IR) absorption spectra of starburst galaxies show several atomic and molecular lines from red supergiants which can be used to infer reliable stellar abundances. The metals locked in stars give a picture of the galaxy metallicity prior to the last burst of star formation. The enrichment of the new generation of stars born in the last burst

Zakir F. Seidov

Exact and approximate analytical formulas are derived for the internal structure and global parameters of the spherical non-rotating quasi-incompressible planet. The planet is modeled by a polytrope with a small polytropic index n << 1, and solutions of the relevant differential equations are obtained analytically, to the second order of n.

Sheperd S. Doeleman, Colin J. Lonsdale, Paul T. Kondratko, C. Read Predmore

We present the first contemporaneous 43GHz and 86GHz VLBI images of the v=1 J=2-1 and J=1-0 SiO masers in the Orion-KL nebula. Both maser species exhibit the same general morphology of earlier J=1-0 maser images which appear to trace the edges of a bi-polar conical outflow. Surprisingly, the J=2-1 masers form further from the central protostar than the J=1-0

B. P. Venemans, H. J. A. Rottgering, G. K. Miley

Recently, we conducted a Very Large Telescope (VLT) large program to search for forming clusters by looking for overdensities of Ly-alpha emitters around high redshift radio galaxies. In total seven proto-clusters were discovered, including a proto-cluster around the radio galaxy MRC 0316--257 at z ~ 3.13. This structure has an excess of Ly-alpha emitters by

T. X. Thuan, F. E. Bauer, P. Papaderos, Y. I. Izotov

We present an X-ray study of the three most metal-deficient blue compact dwarf (BCD) galaxies known in the local Universe, based on deep Chandra observations of SBS 0335-052 (0.025 solar abundance), SBS 0335-052W (0.02 solar abundance) and I Zw 18 (0.02 solar abundance). All three are detected, with more than 90% of their X-ray emission arising from point-li

Maxim Lyutikov, Martin Pohl

At the early, ejecta dominated, stage of supernova remnant (SNR) expansion a fraction of the swept-up circumstellar magnetic field is dynamically compressed to approximate equipartition at the contact discontinuity separating the SN progenitor&#39;s wind (or the ISM) and the ejecta. We propose that the thin non-thermal X-ray filaments observed by the Chandra

K. Sasaki, Y. Kawazoe, R. Saito

The effects of graphite surface geometrical deformation on the dynamics of conducting electrons are investigated theoretically. The analysis is performed within the framework of a deformation-induced gauge field and corresponding deformation-induced magnetic field. It is shown that the latter gives a local energy gap along the axis of a deformed nanotube. We

Friedrich W. Hehl, Yuri N. Obukhov

We extend an axiomatic approach to classical electrodynamics, which we developed recently, to the case of non-vanishing magnetic charge. Then two axioms, namely those of the existence of the Lorentz force (Axiom 2) and of magnetic flux conservation (Axiom 3) have to be generalized. Electric/magnetic reciprocity constitutes a guiding principle for this undert

P. I. Hurtado, J. Marro, P. L. Garrido

The metastable behavior of a kinetic Ising--like ferromagnetic model system in which a generic type of microscopic disorder induces nonequilibrium steady states is studied by computer simulation and a mean--field approach. We pay attention, in particular, to the spinodal curve or intrinsic coercive field that separates the metastable region from the unstable