March 2001 arXiv papers — page 10

D. T. Son, M. A. Stephanov

We consider a system of two interpenetrating Bose-Einstein condensates of atoms in two different hyperfine spin states. We show that in the presence of a small coupling drive between the two spin levels, there exist domain walls across which the relative phase of the two condensates changes by 2pi. We give the physical interpretation of such walls. We show t

V. A. Miransky, G. W. Semenoff, I. A. Shovkovy, L. C. R. Wijewardhana

The possibility of generating a color superconducting state in 2+1 dimensional QCD is analyzed. The gap equation in the leading, hard-dense loop improved, one-gluon exchange approximation is derived and solved. The magnitude of the order parameter is proportional to a power of the coupling constant. For an asymptotically large chemical potential, a qualitate

P. Desrosiers, L. Lapointe, P. Mathieu

A new generalization of the Jack polynomials that incorporates fermionic variables is presented. These Jack superpolynomials are constructed as those eigenfunctions of the supersymmetric extension of the trigonometric Calogero-Moser-Sutherland (CMS) model that decomposes triangularly in terms of the symmetric monomial superfunctions. Many explicit examples a

A. Rosch

In the antiferromagnetically ordered phase of a metal, gaps open on parts of the Fermi surface if the Fermi volume is sufficiently large. We discuss simple qualitative and heuristic arguments under what conditions precursor effects, i.e. pseudo gaps, are expected in the paramagnetic phase of a metal close to an antiferromagnetic quantum phase transition. At

Edmund J. Copeland, David Lyth, Arttu Rajantie, Mark Trodden

We consider the construction of inverted hybrid inflation models in which the vacuum energy during inflation is at the TeV scale, and the inflaton couples to the Higgs field. Such models are of interest in the context of some recently proposed models of electroweak baryogenesis. We demonstrate how constraints on these models arise from quantum corrections, a

C. Rubano, P. Scudellaro

We present general exact solutions for two classes of exponential potentials in scalar field models for quintessence. The coupling is minimal and we consider only dust and scalar field. To some extent, it is possible to reproduce experimental results from supernovae.

Bo Feng, Yang-Hui He, Andreas Karch, Angel Uranga

We establish T-duality between NS5 branes stuck on an orientifold 8-plane in type I' and an orientifold construction in type IIB with D7 branes intersecting at angles. Two applications are discussed. For one we obtain new brane constructions, realizing field theories with gauge group a product of symplectic factors, giving rise to a large new class of co

L. Costamante, G. Ghisellini, P. Giommi, G. Tagliaferri

We performed an observational program with the X-ray satellite BeppoSAX to study objects with extreme synchrotron peak frequencies (nu_peak > 1 keV). Of the seven sources observed, four showed peak frequencies in the range 1-5 keV, while one (1ES 1426+428) displayed a flat power law spectrum (alpha= 0.92), locating its synchrotron peak at or above 100 keV. T

J. C. Egues, C. Gould, G. Richter, L. W. Molenkamp

We theoretically investigate magnetoresistance (MR) effects in connection with spin filtering in quantum-coherent transport through tunnel junctions based on non-magnetic/semimagnetic heterostructures. We find that spin filtering in conjunction with the suppression/enhancement of the spin-dependent Fermi seas in semimagnetic contacts gives rise to (i) spin-s

R. Jeannerot, S. Khalil, G. Lazarides

We present a concrete supersymmetric grand unified model based on the Pati-Salam gauge group SU(4)_c x SU(2)_L x SU(2)_R and leading naturally to smooth hybrid inflation, which avoids the cosmological disaster encountered in the standard hybrid inflationary scenario from the overproduction of monopoles at the end of inflation. Successful `reheating' whic

Mahendra K. Verma

A self-consistent renormalization (RG) scheme has been applied to nonhelical magnetohydrodynamic turbulence with normalized cross helicity $σ_c =0$ and $σ_c \to 1$. Kolmogorov's 5/3 powerlaw is assumed in order to compute the renormalized parameters. It has been shown that the RG fixed point is stable for $d \ge d_c \approx 2.2$. The renormalized viscosi

S. Booth, M. Göckeler, R. Horsley, A. C. Irving

The scale parameter $Λ_{\overline{MS}}$ is computed on the lattice in the quenched approximation and for $N_f = 2$ flavors of light dynamical quarks. The dynamical calculation is done with non-perturbatively $O(a)$ improved Wilson fermions. In the continuum limit we obtain $Λ_{\overline{MS}}^{N_f=0} = 243(1)(10)$ MeV and $Λ_{\overline{MS}}^{N_f=2} = 217(16)(

John Calsamiglia, Matt Mackie, Kalle-Antti Suominen

We theoretically examine photoassociation of a non-ideal Bose-Einstein condensate, focusing on evidence for a macroscopic superposition of atoms and molecules. This problem raises an interest because, rather than two states of a given object, an atom-molecule system is a seemingly impossible macroscopic superposition of different objects. Nevertheless, photo

Everton M. C. Abreu, Alvaro de Souza Dutra

In this work we prove in a precise way that the soldering formalism can be applied to the Srivastava chiral boson (SCB), in contradiction with some results appearing in the literature. We have promoted a canonical transformation that shows directly that the SCB is composed of two Floreanini-Jackiw's particles with the same chirality which spectrum is a v

Marcos Curty, David J. Santos

Although key distribution is arguably the most studied context on which to apply quantum cryptographic techniques, message authentication, i.e., certifying the identity of the message originator and the integrity of the message sent, can also benefit from the use of quantum resources. Classically, message authentication can be performed by techniques based o

Piotr Sniady, Roland Speicher

We show that every R-diagonal operator x has a continuous family of invariant subspaces relative to the von Neumann algebra generated by x. This allows us to find the Brown measure of x and to find a new conceptual proof that Voiculescu's S-transform is multiplicative. Our considerations base on a new concept of R-diagonality with amalgamation, for which

Alexander Schekochihin, Stanislav Boldyrev, Russell Kulsrud

The existence of a weak galactic magnetic field has been repeatedly confirmed by observational data. The origin of this field has not as yet been explained in a fully satisfactory way and represents one of the main challenges of the astrophysical dynamo theory. In both the galactic dynamo theory and the primordial-origin theory, a major influence is exerted

Neil J. Cornish, Shane L. Larson

It is thought that a stochastic background of gravitational waves was produced during the formation of the universe. A great deal could be learned by measuring this Cosmic Gravitational-wave Background (CGB), but detecting the CGB presents a significant technological challenge. The signal strength is expected to be extremely weak, and there will be competiti

Z. Y. Fan, D. G. Hinks, N. Newman, J. M. Rowell

The thermal stability of MgB2 has been studied experimentally to determine the role of thermodynamic and kinetic barriers in the decomposition process. The MgB2 decomposition rate approaches one monolayer per second at 650 C and has an activation energy of 2.0 eV. The evaporation coefficient is inferred to be ~ 10(-4), indicating that this process is kinetic

Bo-yu Hou, W. -L. Yang, Y. Zhen

We construct a realization of the central extension of super-Yangian double $DY_{\hbar}(\hat{sl}(M+1|N+1))$ at level-one in terms of free boson fields with a continuous parameter.

J. P. Ma, Jia-Sheng Xu

We study the exclusive decay of $1^{--}$ heavy quarkonium into one photon and two pions in the kinematic region, where the two-pion system has a invariant mass which is much smaller than the mass of heavy quarkonium. Neglecting effects suppressed by the inverse of the heavy quark mass, the decay amplitude can be factorized, in which the nonperturbative effec

Mitsuo J. Hayashi

Consistency conditions for the local existence of massless spin 3/2 fields has been explored that the field equations for massless helicity 3/2 are consistent iff the space-time is Ricci-flat and that in Minkowski space-time the space of conserved charges for the fields is its twistor space itself. After considering the twistorial methods to study such massl

Denis Dalidovich, Philip Phillips

We analyze here the behavior near the 2D insulator-superconductor quantum critical point in the presence of a perpendicular magnetic field. We show that with increasing field $H$, the quantum disordered and quantum critical regimes, in which vortex degrees of freedom are suppressed, crossover to a new magnetically activated (MA) regime, where the correlation

Kunihiko Yamaji

Using the tight-binding method for the $π$-bands in MgB$_2$, the Hubbard on-site Coulomb interaction on two inequivalent boron $p_z$-orbitals is transformed into expressions in terms of $π$-band operators. For scattering processes relevant to the problemin which a wave vector {\bf q} is parallel to $\hat{z}$, it is found to take a relatively simple form cons

Vijay Balasubramanian, Petr Horava, Djordje Minic

Semiclassical gravity predicts that de Sitter space has a finite entropy. We suggest a picture for Euclidean de Sitter space in string theory, and use the AdS/CFT correspondence to argue that de Sitter entropy can be understood as the number of degrees of freedom in a quantum mechanical dual.

Satoshi Fujimoto

We investigate the interplay between geometrical frustration and strong electron correlation based upon the pyrochlore Hubbard model. In the half-filling case, using the perturbative expansion in terms of electron correlation, we show that the self-energy shows a divergent behavior leading the system into the Mott insulating state, in which quantum disordere

Olivier Pfister, William J. Brown, Michael D. Stenner, Daniel J. Gauthier

We describe the operating characteristics of a new type of quantum oscillator that is based on a two-photon stimulated emission process. This two-photon laser consists of spin-polarized and laser-driven $^{39}$K atoms placed in a high-finesse transverse-mode-degenerate optical resonator, and produces a beam with a power of $\sim $0.2 $μ$W at a wavelength of

Tsao Chang

Based on experimental evidences supporting the hypothesis that neutrinos might be spacelike particles, a new Dirac-type equation is proposed and a spin-1/2 spacelike quantum theory is developed. The new Dirac-type equation provides a solution for the puzzle of negative mass-square of neutrinos. This equation can be written in two spinor equations coupled tog

Daniel F. V. James, Paul G. Kwiat, William J. Munro, Andrew G. White

We describe in detail the theory underpinning the measurement of density matrices of a pair of quantum two-level systems (``qubits''). Our particular emphasis is on qubits realized by the two polarization degrees of freedom of a pair of entangled photons generated in a down-conversion experiment; however the discussion applies in general, regardless

S. D. Bartlett, D. A. Rice, B. C. Sanders, J. Daboul

It is shown that optical experimental tests of Bell inequality violations can be described by SU(1,1) transformations of the vacuum state, followed by photon coincidence detections. The set of all possible tests are described by various SU(1,1) subgroups of Sp(8,$\Bbb R$). In addition to establishing a common formalism for physically distinct Bell inequality

A. M. Chechelnitsky

As is known, the Standard Model mainly ideologically and qualitatively focuss the experimenters in their search of new mass states (of EP- elementary particles). The exact quantitative prognosis of their properties, especially of masses, lays outside opportunities of the usual theory. Model of Stationary states of EP within the framework of the Wave Universe

A. M. Chechelnitsky

In the frame of Wave Universe Concept (WU Concept) it is presented the alternative approach to the effective description of Elementar Objects of Matter (EOM) of micro and megaworld hierarchy, in particular, of particles in subatomic physics. According to the Wave Universe Concept (WU Concept), discrete spectrum of EOM is close connected, generate by universa

Alexander A. Vlasov

In previous work (physics/0004026) was shown, with the help of numerical calculations, that the effective Brown temperature for charged particle is lower than that for particle without charge. Here we derive this result without numerical calculations, integrating the delay equation analytically, as for zero, so for nonzero viscosity.

Takuya Nakano, Masayuki Matsuzaki

We calculate the specific heat of the inner crust of neutron stars within a local-density approximation to an improved relativistic Hartree-Bogoliubov theory. Non-uniformness of the system enhances the specific heat in particular at low temperatures. The degree of enhancement is similar to that in the spherical phase of Elgarøy et al. We examine a schematic

Tapan K. Nayak

Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158$\cdot A$ GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as $N_{part}^{1.07\pm 0.05}$ and photons as $N_{part

R. F. Streater

We study coupled non-linear parabolic equations for a fluid described by a material density and a temperature, both functions of space and time. In one dimension, we find some stationary solutions corresponding to fixing the temperature on the boundary, with no-escape boundary conditions for the material. For the special case, where the temperature on the bo

P. J. Forrester, N. S. Witte

Tracy and Widom have evaluated the cumulative distribution of the largest eigenvalue for the finite and scaled infinite GUE in terms of a PIV and PII transcendent respectively. We generalise these results to the evaluation of $\tilde{E}_N(λ;a) := \Big < \prod_{l=1}^N χ_{(-\infty, λ]}^{(l)} (λ- λ_l)^a \Big>$, where $ χ_{(-\infty, λ]}^{(l)} = 1$ for $λ_l \in (

Jeong-Hyuck Park

We study two supersymmetric toy models of a k-form superfield, k=2,1 separately. By ``solving&#39;&#39; Jacobi identities, we show that each model is completely solvable at off-shell level, possesses a severely constrained kinematics, and gives a rigid representation of the supersymmetry algebra. This study of the toy models is motivated by our reanalysis on

Walter Van Assche, Els Coussement

Recently there has been a renewed interest in an extension of the notion of orthogonal polynomials known as multiple orthogonal polynomials. This notion comes from simultaneous rational approximation (Hermite-Pade approximation) of a system of several functions. We describe seven families of multiple orthogonal polynomials which have he same flavor as the ve

Claudio Arezzo, Frank Pacard

In this paper we prove the existence of families of n-dimensional complete embedded minimal submanifolds of C^n with a prescribed configuration of k>1 asymptotic planes. These submanifolds are obtained by desingularizing the intersection of the asymptotes, using a gluing theorem applied to a generalization of a special lagrangian &#34;hyperbola&#34; found by

N. F. Benschop

Constant Rank (CR) state machines play an important role in the general structure theory of Finite State Machines. A machine is of constant rank if each input and input-sequence maps the state set onto the same number of next states. CR-machines are analysed via their sequential closure (semigroup), which is a simple semigroup, thus: a semi- direct product (

Michela Varagnolo, Eric Vasserot

We give a proof of the cyclicity conjecture of Akasaka-Kashiwara, for simply laced types, via quiver varieties. We get also an algebraic characterization of the standard modules.

Alexei Nurmagambetov

A relation between dimensional reduction and space-time symmetry gauging is outlined.

N. B. Pomeroy

A one-instanton level test is performed for the proposed reparameterisation scheme matching the conjectured exact low energy results and instanton predictions for N=2 supersymmetric SU(N) gauge theories with 2N massless fundamental matter hypermultiplets across the entire quantum moduli space. The constants within the scheme which ensure agreement between th

S. Bellucci, V. Faraoni, D. Babusci

The response of a gravitational wave detector to scalar waves is analysed in the framework of the debate on the choice of conformal frames for scalar-tensor theories. A correction to the geodesic equation arising in the Einstein conformal frame modifies the geodesic deviation equation. This modification is due to the non-metricity of the theory in the Einste

Harald Grosse, Karl-Georg Schlesinger

We suggest that trialgebraic symmetries migth be a sensible starting point for a notion of integrability for two dimensional spin systems. For a simple trialgebraic symmetry we give an explicit condition in terms of matrices which a Hamiltonian realizing such a symmetry has to satisfy and give an example of such a Hamiltonian which realizes a trialgebra rece

Masato Arai, Nobuchika Okada

We analyze the vacuum structure of spontaneously broken N=2 supersymmetric gauge theory with the Fayet-Iliopoulos term. Our theory is based on the gauge group SU(2) \times U(1) with N_f=2 massless quark hypermultiplets having the same U(1) charges. In the classical potential, there are degenerate vacua even in the absence of supersymmetry. It is shown that t

C. Ford, G. Jorjadze, G. Weigt

Using a gauge invariant reduction we directly integrate the SL(2,R)/U(1) WZNW theory. We prove that the conserved parafermions of this theory are coset currents. Quantum mechanically, the parafermion algebra, the energy-momentum tensor, and `auxiliary&#39; parafermions are deformed in a self-consistent manner.

T. Frederico, H. -C. Pauli

The renormalization of the effective QCD-Hamiltonian theory for the quark-antiquark channel is performed in terms of a renormalized or fixed-point Hamiltonian that leads to subtracted dynamical equations. The fixed point-Hamiltonian brings the renormalization conditions as well as the counterterms that render the theory finite. The approach is renormalizatio

Prashanth Jaikumar, Ismail Zahed

We compare the BCS and Overhauser effect as competing mechanisms for the destabilization of the quark Fermi surface at asymptotically large chemical potential, for the special case of 2 space and 1 time dimension. We use the framework of perturbative one-gluon exchange, which dominates the pairing at $μ/g^2\gg 1$. With screening in matter, we show that in th

K. G. Chetyrkin, A. L. Kataev, A. B. Krasulin, A. A. Pivovarov

The QCD finite energy sum rules method is used to show that the parameter of the K^0-\bar{K}_0 mixing \hat{B} is mainly determined by the value of g m_s< \bar{d} G_{μν} σ_{μν} d > and the vacuum expectation values of four-quark operators. Assuming the hypothesis of vacuum dominance and/or unitarity symmetry to estimate latter, it is found that \hat{B}=1.2\pm

Y. Brihaye, V. A. Rubakov, D. H. Tchrakian, F. Zimmerschied

We present a simple model where a nucleon is treated as the Skyrmion, both monopole and Skyrmion are smooth solutions of the classical field equations,the baryon number non-conservation is explicitly built in and is due to the classical analogue of the triangle anomaly, and there is no necessity to consider leptons. We show by numerical analysis that there a

Wojciech Krolikowski

A form of mixing matrix for three active and three sterile, conventional Majorana neutrinos is proposed. Its Majorana lefthanded part arises from the popular bimaximal mixing matrix for three active neutrinos that works satisfactorily in solar and atmospheric experiments if the LSND effect is ignored. One of three sterile neutrinos, effective in the Majorana

E. Manfredini

This work is devoted to the study of relaxation--dissipation processes in systems described by Quantum Field Theory. In the first part, I focus on the phi^4 scalar quantum field theory in finite volume in the large N limit. I find that the zero-mode quantum fluctuations cannot grow macroscopically large starting from microscopic initial conditions, while the

E. von Toerne, J. Burns, J. Duboscq, E. Eckhart

The CLEO III detector has recently commenced data taking at the Cornell electron Storage Ring (CESR). One important component of this detector is a 4 layer double-sided silicon tracker with 93% solid angle coverage. This detector ranges in size and number of readout channels between the LEP and LHC silicon detectors. In order to reach the detector performanc

Anders Ryd

BABAR has studied the time dependent asymmetries in the the decays B0 -> J/psi K0S and B0 -> psi(2S) K0S in a data set of 9.0 fb^-1 taken at the Y(4S)resonance. In these channels we reconstruct 168 events of which 120 are flavor tagged and used in a likelihood fit where we determine sin2beta. The flavor of the other neutral $B$ mesons is tagged using informa

The DELPHI Collaboration, P. Abreu

The data collected by DELPHI in 1998 at the centre-of-mass energy of 189 GeV have been used to update the search for charginos nearly mass-degenerate with the lightest supersymmetric particle, which is assumed to be the lightest neutralino. Mass differences below ΔM = 3 GeV/c^2 are considered. No excess of events with respect to the Standard Model expectatio

The DELPHI Collaboration, P. Abreu

Searches for supersymmetric partners of top and bottom quarks are presented using data taken by the DELPHI experiment at LEP in 1997 and 1998. No deviations from standard model expectations are observed in these data sets, which are taken at centre-of-mass energies of 183 GeV and 189 GeV and correspond to integrated luminosities of 54 pb^{-1} and 158 pb^{-1}

M. J. Konstantinovic, J. C. Irwin, M. Isobe, Y. Ueda

In the (ab) polarized Raman scattering spectra of NaV2O5 single crystals, measured with 647.1 nm laser line at T < Tc, we found two modes at 86, and 126 cm-1 not previously reported. These two modes, together with 66, and 106 cm-1 modes, make an array of four low-energy equidistant modes below the energy onset of the continuum at about 132 cm-1. All four mod

Eric F. Preston, Jorge S. Sá Martins, John B. Rundle

Mean field slider block models have provided an important entry point for understanding the behavior of discrete driven threshold systems. We present a method of constructing these models with an arbitrary frictional weakening function. This `forced weakening&#39; method unifies several existing approaches, and multiplies the range of possible weakening laws

F. Ricci-Tersenghi, G. Parisi, D. A. Stariolo, J. J. Arenzon

In a Comment (cond-mat/0103444) on our recent paper &#34;Two time scales and violation of FDT in a finite dimensional model for structural glasses&#34; [1], A. de Candia and A. Coniglio show evidence that the equilibrium overlap distribution P(q) of the frustrated Ising lattice gas (FILG) does not coincide with the one that could be estimated from the off-eq

Lev P. Gor&#39;kov, Emmanuel I. Rashba

Motivated by recent experimental findings, we have developed a theory of the superconducting state for 2D metals without inversion symmetry modeling the geometry of a surface superconducting layer in a field-effect-transistor or near the boundary doped by adsorbed ions. In such systems the two-fold spin degeneracy is lifted by spin-orbit interaction, and sin

A. de Candia, A. Coniglio

In cond-mat/0002074 Ricci-Tersenghi et al. find two linear regimes in the fluctuation-dissipation relation between density-density correlations and associated responses of the Frustrated Ising Lattice Gas. Here we show that this result does not seem to correspond to the equilibrium quantities of the model, by measuring the overlap distribution P(q) of the de

Joachim Krug

Evolutionary dynamics in an uncorrelated rugged fitness landscape is studied in the framework of Eigen&#39;s molecular quasispecies model. We consider the case of strong selection, which is analogous to the zero temperature limit in the equivalent problem of directed polymers in random media. In this limit the population is always localized at a single tempo

V. A. Pashchenko, A. Sulpice, F. Mila, P. Millet

We report on the magnetic susceptibility and electron spin resonance measurements on polycrystalline samples of the vanadium oxide VOSb$_{2}$O$_{4}$, a quasi-one dimensional S=1/2 Heisenberg system. We show that the susceptibility vanishes at zero temperature, as in a gapped system, and we argue that this is due to a spin-Peierls transition with strong struc

Georges Debregeas, Herve Tabuteau, Jean-Marc di Meglio

We investigate the flow properties of a two-dimensional aqueous foam submitted to a quasistatic shear in a Couette geometry. A strong localization of the flow (shear banding) at the edge of the moving wall is evidenced, characterized by an exponential decay of the average tangential velocity. Moreover, the analysis of the rapid velocity fluctuations reveals

H. S. J. van der Zant, E. Slot, S. V. Zaitsev-Zotov, S. N. Artemenko

Charge-density-wave dynamics is studied on a submicron length scale in NbSe_3 and o-TaS_3. Regions of negative absolute resistance are observed in the CDW sliding regime at sufficiently low temperatures. The origin of the negative resistance is attributed to the different forces that the deformed CDW and quasi-particles feel: the force on the CDW is merely c

M. Windt, M. Grueninger, T. Nunner, C. Knetter

Phonon-assisted 2-magnon absorption is studied at T=4 K in the spin-1/2 two-leg ladders of Ca_14-x La_x Cu_24 O_41 (x=5 and 4) for polarization of the electrical field parallel to the legs and the rungs, respectively. Two peaks at about 2140 and 2800 1/cm reflect van-Hove singularities in the density of states of the strongly dispersing 2-magnon singlet boun

O. Narikiyo

The Hall angle in the doped V_2O_3 is discussed on the basis of an extended Ginzburg-Landau theory of spin fluctuations. A spinon-like collective transport process beyond the ordinary quasiparticle transport theory is necessary to understand the experiment. At the same time a criticism of a quasiparticle transport theory on the basis of the fluctuation excha

Yuriy I. Kuzmin

The surface discharge of electrified dielectrics at high humidity is considered. The percolative nature of charge transport in electrets is established. Particular attention is given to the phenomena of adsorption and nucleation of electrically conducting phase in the cause of percolation cluster growth on electrified surface. The critical index of the corre

Charanbir kaur, Shankar P. Das

We incorporate the role of free volume in the density function of the amorphous structure and study its effects on the stability of such structures. The Density Functional Theory is used to explore this ``Free Volume Model&#39;&#39; of the supercooled structures. The Free energy minimization is carried out using the void concentration as a variational parame

D. Lacoste, T. C. Lubensky

In the presence of a magnetic field applied perpendicular to a thin sample layer, a suspension of magnetic colloidal particles (ferrofluid) can form spatially modulated phases with a characteristic length determined by the competition between dipolar forces and short-range forces opposing density variations. We introduce models for thin-film ferrofluids in w

Malcolm P. Kennett, Claudio Chamon, Jinwu Ye

We study the long time dynamics of quantum spin glasses of rotors using the non-equilibrium Schwinger-Keldysh formalism. These models are known to have a quantum phase transition from a paramagnetic to a spin glass phase, which we approach by looking at the divergence of the spin relaxation rate at the transition point. In the aging regime, we determine the

T. T. Nguyen, A. Yu. Grosberg, B. I. Shklovskii

We review works on screening of a macroion, such as colloidal particle or double helix DNA, by multivalent counterions. Multivalent metal ions, charged micelles, short or long polyelectrolytes can play the role of multivalent counterions. Due to the strong Coulomb repulsion such multivalent counterions form a strongly correlated liquid resembling a Wigner cr

Maria Teresa Ruiz, Patricio M. Rojo, Guido Garay, Jose Maza

We present spectroscopic observations of object CE-315 revealing a blue continuum with strong emission lines. Most of the detected lines are identified with He I or He II in emission with a handful of faint lines of nitrogen. Notable is the complete absence of hydrogen lines. The He lines exhibit triple-peaked profiles with remakably broad widths, of about 2

A. Quirrenbach, J. E. Roberts, K. Fidkowski, W. de Vries

We present seeing-limited and adaptive optics (AO) images of the z = 1.786 radio galaxy 3C294 in the H and K&#39; infrared bands obtained at Keck Observatory. The infrared emission of 3C294 is dominated by two distinct components separated by ~1&#34; (9 kpc). The eastern knot contains an unresolved core that contributes ~4% of the K&#39;-band light; we ident

Daniel D. Kelson, Garth D. Illingworth, Marijn Franx, Pieter G. van Dokkum

We present new results from a systematic study of absorption line strengths of galaxies in clusters approaching redshifts of unity. In this paper, we specifically compare the strengths of the high-order Balmer absorption features of Hgamma and Hdelta in E/S0s in the four clusters Abell 2256 (z=0.06), CL1358+62 (z=0.33), MS2053--04 (z=0.58), and MS1054--03 (z

Milos Milosavljevic, David Merritt

We investigate a model in which galactic nuclei form via the coalescence of pre-existing stellar systems containing supermassive black holes. Merger simulations are carried out using N-body algorithms that can follow the formation and decay of a black-hole binary and its effect on the surrounding stars down to sub-parsec scales. Our initial stellar systems h

H. R. E. Tjin A Djie, M. E. van den Ancker, P. F. C. Blondel, V. S. Shevchenko

We present new high and low resolution spectroscopic and photometric data of nine members of the young association CMa R1. All the stars have circumstellar dust at some distance as could be expected from their association with reflection nebulosity. Four stars (HD 52721, HD 53367, LkHalpha 220 and LkHalpha 218) show Halpha emission and we argue that they are

Alberto Moretti, Luigi Guzzo, Sergio Campana, Stefano Covino

We describe the main features of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep optical CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys and will provide us wit

Yvonne Simis, Vincent Icke, Carsten Dominik

We have combined time dependent hydrodynamics with a two-fluid model for dust driven AGB winds. Our calculations include self-consistent gas chemistry, grain formation and growth, and a new implementation of the viscous momentum transfer between grains and gas. This allows us to perform calculations in which no assumptions about the completeness of momentum

Riccardo Giovanelli, Jeremy Darling, Charles Henderson, William Hoffman

We discuss properties of the atmospheric water vapor above the high Andean plateau region known as the Llano de Chajnantor, in the Atacama Desert of northern Chile. A combination of radiometric and radiosonde measurements indicate that the median column of precipitable water vapor (PWV) above the plateau at an elevation of 5000 m is approximately 1.2 mm. The

Riccardo Giovanelli, Jeremy Darling, Marc Sarazin, Jennifer Yu

The region surrounding the Llano de Chajnantor, a high altitude plateau in the Atacama Desert in northern Chile, has caught the attention of the astronomical community for its potential as an observatory site. Combining high elevation and extremely low atmospheric water content, the Llano has been chosen as the future site of the Atacama Large Millimeter Arr

R. Coziol, R. Doyon, S. Demers

(Abridged) We present new K-band spectroscopy for a sample of 48 starburst galaxies, obtained using UKIRT in Hawaii. This constitutes a fair sample of the most common types of starburst galaxies found in the nearby Universe. The variety of near infrared spectral features shown by these galaxies implies different bursts characteristics, which suggests that we

P. F. L. Maxted, U. Heber, T. R. Marsh, R. C. North

(Abbreviated) We have used precise radial velocity measurements of subdwarf-B stars from the Palomar-Green catalogue to look for binary extreme horizontal branch (EHB) stars. We identify 36 EHB stars in our sample and find that at least 21 of these stars are binaries. All but one or two of these are new identifications. The minimum binary fraction for EHB st

Ya. N. Istomin, A. V. Makarov

It is suggested that the accretion disk excites the eigen modes of Alfven oscillations of the magnetic field tubes the ends of which are frozen to the neutron star surface. The resonance takes place when the eigen Alfven frequency coincides with the difference of the Keplerian disk rotation frequency and the frequency of rotation of a neutron star. This mode

Peter Barthel

The symbiosis of nuclear activity and star-formation in galaxies, as manifested in their spectral energy distributions (SEDs) is reviewed. Attention is drawn to an Hertzsprung-Russell diagram-equivalent for such objects, as well as to the importance of the SEDs in cosmological context.

C. W. Straka, W. M. Tscharnuter

Time-dependent nuclear network calculations at constant temperature show that for zero-metal stars >= 20 Msun (i) beta-decay reactions and (ii) the 13N(p,gamma)14O reaction must be included. It is also shown that the nuclear timescale in these zero-metal stars is shorter than the mixing timescale and therefore the assumption of instantaneous mixing across co

L. B. Lucy

Superlevel partitioning is combined with a simple relaxation procedure to construct an iterative technique for solving equations of statistical equilibrium. In treating an $N$-level model atom, the technique avoids the $N^{3}$ scaling in computer time for direct solutions with standard linear equation routines and also does not fail at large $N$ due to the a

P. Ventura, F. D&#39;Antona, I. Mazzitelli, R. Gratton

Full evolutionary models have been built to follow the phases of asymptotic giant branch evolution with mass loss for metal mass fractions from Z=0.0002 to Z=0.004. For the first time, we find that temperatures close to or even larger than 10^8 K are achieved at low Z; the full CNO cycle operates at the base of the envelope, the Oxygen abundance for the most

L. Ciotti, T. S. van Albada

Most elliptical galaxies contain central black holes, whose masses scale proportionally to the observed central velocity dispersions of the host galaxies according to the so-called Mbh-sigma relation. Here we discuss some consequences that can be derived by combining the Mbh-sigma relation with the scaling relation describing the Fundamental Plane of ellipti

M. Momose, M. Tamura, O. Kameya, J. S. Greaves

Imaging polarimetry of the 0.85mm continuum emission in the NGC 7538 region, obtained with the SCUBA Polarimeter, is presented. The polarization map is interpreted in terms of thermal radiation by magnetically aligned dust grains. Two prominent cores associated with IRS 1 and IRS 11, IRS 1(SMM) and IRS 11(SMM), are found in the surface brightness map. Althou

Gabriela Canalizo, Alan Stockton

We test the hypothesis that QSOs are formed via strong tidal interactions or mergers, initially going through an ultraluminous infrared phase, by looking for traces to this phase in the host galaxies of QSOs. We present a systematic spectroscopic and imaging study of a sample of QSOs that may be in a transitionary stage. By modeling the spectra, we obtain ag

M. Bonamente, R. Lieu, J. Nevalainen, J. S. Kaastra

Excess soft X-ray emission in clusters of galaxies has so far been detected for sources that lie along lines-of-sight to very low Galactic HI column density (such as Coma, A1795, A2199 and Virgo, N_H 0.9-2.0 10^{20} cm-2). We show that the cluster soft excess emission can be investigated even at higher N_H, which provides an opportunity for investigating sof

R. V. E. Lovelace, H. Li, G. V. Ustyugova, M. M. Romanova

The powerful narrow jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the disk. Two main regimes have been discussed, {\it hydromagnetic outflows}, which have a significant mass flux

Lam Hui, Sara Seager

Future high precision photometric measurements of transiting extrasolar planets promise to tell us much about the nature of these systems. We examine how atmospheric lensing and (projected) planet oblateness/ellipticity modify transit light curves. The large density gradients expected in planet atmospheres can offset the unfavorably large observer-lens to so

M. Cvetic, G. W. Gibbons, H. Lu, C. N. Pope

We construct new explicit metrics on complete non-compact Riemannian 8-manifolds with holonomy Spin(7). One manifold, which we denote by A_8, is topologically R^8 and another, which we denote by B_8, is the bundle of chiral spinors over $S^4$. Unlike the previously-known complete non-compact metric of Spin(7) holonomy, which was also defined on the bundle of

Ivica Res

Recently Grassberger has shown that the correction to scaling for the conductance of a bond percolation network on a square lattice is a nonmonotonic function of the linear lattice dimension with a minimum at $L = 10$, while this anomalous behavior is not present in the site percolation networks. We perform a high precision numerical study of the bond percol

Oleg Lunin, Samir D. Mathur

The D1-D5 system is believed to have an `orbifold point&#39; in its moduli space where its low energy theory is a N=4 supersymmetric sigma model with target space M^N/S^N, where M is T^4 or K3. We study correlation functions of chiral operators in CFTs arising from such a theory. We construct a basic class of chiral operators from twist fields of the symmetr

Jose D. Edelstein, Carlos Nunez

We study the supergravity duals of supersymmetric theories arising in the world-volume of D6 branes wrapping holomorphic two-cycles and special Lagrangian three-cycles within the framework of eight dimensional gauged supergravity. When uplifted to 11d, our solutions represent M-theory on the background of, respectively, the small resolution of the conifold a