April 2006 arXiv papers — page 28

K. M. Indlekofer, J. Knoch, J. Appenzeller

With the help of a multi-configurational Green's function approach we simulate single-electron Coulomb charging effects in gated ultimately scaled nanostructures which are beyond the scope of a selfconsistent mean-field description. From the simulated Coulomb-blockade characteristics we derive effective system capacitances and demonstrate how quantum con

Kamil Walczak

Here we study incoherent transport through molecular wire treated as a linear chain of absorbers, where the phase-breaking processes are modeled by the use of imaginary point-like potentials. The calculations are performed within a transfer-matrix method of the scattering theory. An analytic expression for the transmission of a finite chain in obtained, whil

R. Friedrich, F. Jenko, A. Baule, S. Eule

The anomalous (i.e. non-Gaussian) dynamics of particles subject to a deterministic acceleration and a series of 'random kicks' is studied. Based on an extension of the concept of continuous time random walks to position-velocity space, a new fractional equation of the Kramers-Fokker-Planck type is derived. The associated collision operator necessaril

David L. Cheung, Michael P. Allen

The structure of a molecular liquid, in both the nematic liquid crystalline and isotropic phases, around a cylindrical macroparticle, is studied using density functional theory. In the nematic phase the structure of the fluid is highly anisotropic with respect to the director, in agreement with results from simulation and phenomenological theories. On going

Jikeun Seo, Hye-Young Kim, J. -S. Kim

The dynamic effects, such as the steering and the screening effects during deposition, on an epitaxial growth (Cu/Cu(001)), is studied by kinetic Monte Carlo simulation that incorporates molecular dynamic simulation to rigorously take the interaction of the deposited atom with the substrate atoms into account. We find three characteristic features of the sur

Takafumi Kita

This paper presents a conserving gapless mean-field theory for weakly interacting Bose gases. We first construct a mean-field Luttinger-Ward thermodynamic functional in terms of the condensate wave function $Ψ$ and the Nambu Green's function $\hat{G}$ for the quasiparticle field. Imposing its stationarity respect to $Ψ$ and $\hat{G}$ yields a set of equa

T. Senthil

Heavy electron metals on the verge of a quantum phase transition to magnetism show a number of unusual non-fermi liquid properties which are poorly understood. This article discusses in a general way various theoretical aspects of this phase transition with an eye toward understanding the non-fermi liquid phenomena. We suggest that the non-Fermi liquid quant

I. Klebanov, P. Gritsay, N. Ginchitskii

By Wertheim-method the exact solution of the Percus-Yevick integral equation for a system of particles with the repulsive step potential interacting (collapsing hard spheres) is obtained. On the basis of this solution the state equation for the repulsive step potential is built and determined, that the Percus-Yevick equation does not show phase transition fo

J. Tworzydlo, B. Trauzettel, M. Titov, A. Rycerz

We calculate the mode-dependent transmission probability of massless Dirac fermions through an ideal strip of graphene (length L, width W, no impurities or defects), to obtain the conductance and shot noise as a function of Fermi energy. We find that the minimum conductivity of order e^2/h at the Dirac point (when the electron and hole excitations are degene

Yuki Nagai, Yusuke Kato, Nobuhiko Hayashi

We analytically study electronic bound states around a single vortex core in a noncentrosymmetric superconductor such as ${\rm CePt_3Si}$ without mirror symmetry about the $ab$ plane. Considering a mixed spin-singlet-triplet Cooper pairing model, we obtain a formula about the local density of states (LDOS) around a vortex core in any directions of magnetic f

Michael C. Ricci, Steven M. Anlage

We investigate the microwave electrodynamic properties of a single superconducting thin film split-ring resonator (SRR). The experiments were performed in an all-Nb waveguide, with Nb wires and Nb SRRs. Transmission data showed a high-Q stopband for a single Nb SRR ($Q \sim 4.5\times10^4$ at 4.2 K) below $T_c$, and no such feature for a Cu SRR, or closed Nb

Sung-Sik Lee, T. Senthil, Patrick A. Lee

As a sequel to the previous work [Phys. Rev. B 72, 235104 (2005)] we present a vortex description of the fractionalized phase in exciton bose condensate. Magnetic flux line and monopole of the 3+1D emergent U(1) gauge theory are identified in the exciton picture. A bundle of vortex/anti-vortex pairs of all flavors of excitons corresponds to the magnetic flux

O. V. Usatenko, S. S. Melnik, V. A. Yampol'skii, M. Johansson

The stationary one-dimensional tight-binding Schredinger equation with a weak diagonal long-range correlated disorder in the potential is studied. An algorithm for constructing the discrete binary on-site potential exhibiting a hybrid spectrum with three different spectral components (absolutely continuous, singular continuous and point) ordered in any prede

Yajiang Hao, Yunbo Zhang, J. Q. Liang, Shu Chen

We numerically evaluate the density distribution of a spin-1 bosonic condensate in its ground state within a modifed Gross-Pitaevskii theory, which is obtained by the combination of the exact solution of the corresponding integrable model with the local density approximation. Our study reveals that atoms in the m_F = 0 state are almost completely suppressed

M. Giroletti, G. Giovannini, G. B. Taylor, R. Falomo

We present new radio observations of 9 members of a sample of 29 nearby (z < 0.2) BL Lac objects. The new data have been obtained with the European VLBI Network and/or the MERLIN at 1.6 and 5 GHz and complement previous observations. For one object, the TeV source Mrk 421, we also present deep multi-epoch VLBA and Global VLBI data, which reveal a resolved di

Steven Furlanetto

We examine the prospects for studying the pre-reionization intergalactic medium (IGM) through the so-called 21 cm forest in spectra of bright high-redshift radio sources. We first compute the evolution of the mean optical depth for models that include X-ray heating of the IGM gas, Wouthuysen-Field coupling, and reionization. Under most circumstances, the spi

Catherine L. Buchanan, Jack F. Gallimore, Christopher P. O&#39;Dea, Stefi A. Baum

We are conducting a large observing program with the Spitzer Space Telescope to determine the mid-to-far infrared spectral energy distributions of a well-defined sample of 87 nearby, 12 micron-selected Seyfert galaxies. In this paper we present the results of IRS low-resolution spectroscopy of a statistically representative subsample of 51 of the galaxies (5

Eric G. Blackman, Hantao Ji

The term ``dynamo&#39;&#39; means different things to the laboratory fusion plasma and astrophysical plasma communities. To alleviate the resulting confusion and to facilitate interdisciplinary progress, we pinpoint conceptual differences and similarities between laboratory plasma dynamos and astrophysical dynamos. We can divide dynamos into three types: 1.

J. L. Rosenberg, D. V. Bowen, T. M. Tripp, E. Brinks

We present a Very Large Array (VLA) HI 21cm map and optical observations of the region around one of the nearest damped Lyman-alpha absorbers beyond the local group, SBS 1543+593. Two previously uncataloged galaxies have been discovered and a redshift has been determined for a third. All three of these galaxies are at the redshift of SBS 1543+593 and are ~18

J. F. Gallimore, D. J. Axon, C. P. O&#39;Dea, S. A. Baum

Seyfert galaxies commonly host compact jets spanning 10-100 pc scales, but larger structures (KSRs) are resolved out in long baseline, aperture synthesis surveys. We report a new, short baseline Very Large Array (VLA) survey of a complete sample of Seyfert and LINER galaxies. Out of all of the surveyed radio-quiet sources, we find that 44% (19 / 43) show ext

Roban Hultman Kramer, Zoltan Haiman, S. Peng Oh

The reionization history of the intergalactic medium (IGM) at high redshift (z > 6) was likely strongly shaped by several global feedback processes. Because the earliest ionizing sources formed at the locations of the rare density peaks, their spatial distribution was strongly clustered. Here we demonstrate that this clustering significantly boosts the impac

Gabriela Barenboim, Olga Mena Requejo, Chris Quigg

High-energy neutrinos may resonate with relic background neutralinos to form short-lived sneutrinos. In some circumstances, the decay chain that leads back to the lightest supersymmetric particle would yield few-GeV gamma rays or charged-particle signals. Although resonant coannihilation would occur at an appreciable rate in our galaxy, the signal in any for

F. L. Schoeier, H. Olofsson, A. A. Lundgren

New SiO multi-transition millimetre line observations of a sample of carbon stars, including J=8-7 observations with the APEX telescope, are used to probe the role of non-equilibrium chemistry and the influence of grains in circumstellar envelopes of carbon stars. A detailed radiative transfer modelling, including the effect of dust emission in the excitatio

N. P. Abel

The [C II] 158 micron line is an important emission line diagnostic in Photodissociation Regions (PDRs), but this emission line can also emerge from ionized gas. This work calculates the contribution of [C II] emission from ionized gas over a wide range of parameter space by considering the simplified case of an H+ region and PDR in pressure equilibrium. Add

J. Liske, S. P. Driver, P. D. Allen, N. J. G. Cross

We use the Millennium Galaxy Catalogue (MGC) to study the effect of compact galaxies on the local field galaxy luminosity function. Here we observationally define as `compact&#39; galaxies that are too small to be reliably distinguished from stars using a standard star-galaxy separation technique. In particular, we estimate the fraction of galaxies that are

N. P. Abel, G. J. Ferland

The emission line regions of starburst galaxies and active nuclei reveal a wealth of spectroscopic information. A unified picture of the relationship between ionized, atomic, and molecular gas makes it possible to better understand these observations. We performed a series of calculations designed to determine the equation of state, the relationship between

M. A. Thompson, J. Hatchell, A. J. Walsh, G. H. Macdonald

We present a SCUBA submillimetre (450 & 850 micron) survey of the environment of 105 IRAS point sources, selected from the Wood & Churchwell (1989a) and Kurtz, Churchwell & Wood (1994) radio ultracompact (UC) HII region surveys. We detected a total of 155 sub-mm clumps associated with the IRAS point sources and identified three distinct types of object: ultr

P. Picozza, A. Morselli

Many different mechanisms can contribute to antiprotons and positrons production, ranging from conventional reactions up to exotic processes like neutralino annihilation. The open problems are so fundamental (i.e.: is the universe symmetric in matter and antimatter ?) that experiments in this field will probably be of the greatest interest in the next years.

E. S. Cypriano, L. Sodre, J. -P. Kneib, L. E. Campusano

We study the mass distribution of a sample of 24 X-ray bright Abell clusters through weak gravitational lensing. This method is independent of the dynamical state of the galaxy cluster. Hence, by comparing dynamical and lensing mass estimators, we can access the dynamical state of these clusters. We have found that clusters with ICM temperatures above 8 keV

Takuya Akahori, Kuniaki Masai

We investigate the core structure of radiatively cooling intracluster gas, using a hydrodynamics code. We calculate evolution of model clusters of the initial core radii 160--300 kpc until the initial central cooling time, and analyze the resultant clusters using the double beta-model as done by observational studies. It is found that the core-size distribut

Sangwook Park, Svetozar A. Zhekov, David N. Burrows, Gordon P. Garmire

$\sim$18 yr after the supernova explosion, the blast wave of SNR 1987A is entering the main body of the equatorial circumstellar material, which is causing a dramatic brightening of the remnant. We recently reported the observational evidence for this event from our {\it Chandra} data (Park et al. 2005b; P05 hereafter). We present here the temporal evolution

J. Albert et al.

Recently, the HESS array has reported the detection of gamma-ray emission above a few hundred GeV from eight new sources located close to the Galactic Plane. The source HESS J1834-087 is spatially coincident with SNR G23.3-0.3 (W41). Here we present MAGIC observations of this source, resulting in the detection of a differential gamma-ray flux consistent with

J. -J. Fleck, C. M. Boily, A. Lançon, S. Deiters

The mass of unresolved young star clusters derived from spectro-photometric data may well be off by a factor of 2 or more once the migration of massive stars driven by mass segregation is accounted for. We quantify this effect for a large set of cluster parameters, including variations in the stellar IMF, the intrinsic cluster mass, and mean mass density. Ga

Nicola La Palombara, Sandro Mereghetti

We report on the XMM-Newton observation of the Be/neutron star X-ray binary system RX J0146.9+6121, a long period (~ 23 m) pulsar in the NGC 663 open cluster. The X-ray luminosity decreased by a factor two compared to the last observation carried out in 1998, reaching a level of ~ 10^34 erg/s, the lowest ever observed in this source. The spectral analysis re

Marco Onofri, Heinz Isliker, Loukas Vlahos

Electron and proton acceleration in three-dimensional electric and magnetic fields is studied through test particle simulations. The fields are obtained by a three-dimensional magnetohydrodynamic simulation of magnetic reconnection in slab geometry. The nonlinear evolution of the system is characterized by the growth of many unstable modes and the initial cu

F. R. Marleau, A. Noriega-Crespo, K. A. Misselt, K. D. Gordon

We present observations at 3.6, 4.5, 5.8, 8, 24, 70 & 160um of NGC 205, the dwarf elliptical companion of M31, obtained with the Spitzer Space Telescope. The point sources subtracted images at 8 and 24um display a complex and fragmented infrared emission coming from both very small dust particles and larger grains. The extended dust emission is spatially con

G. Y. Liang, G. Zhao, J. R. Shi

Electron density diagnostics based on a line intensity ratio of Si X are applied to the X-ray spectra of Procyon, $α$ Cen A$&$B, Capella and $ε$ Eri measured with the Low Energy Transmission Grating Spectrometer (LETGS) combined with High-resolution Camera (HRC) on board the {\it Chandra X-ray Observatory}. The ratio $R_1$ of the intensities of the Si X line

Jacco Vink, Lucien Kuiper

It is generally accepted that Anomalous X-ray Pulsars (AXPs) and Soft Gamma-ray Repeaters (SGRs) are magnetars, i.e. neutron stars with extremely high surface magnetic fields ($B > 10^{14}$ G). The origin of these high magnetic fields is uncertain, but a popular hypothesis is that magnetars are born with an initial spin period not much exceeding the convecti

Melvyn B. Nathanson

This is the text of a lecture at the Logic Conference in Memory of Stanley Tennenbaum at the CUNY Graduate Center on April 7, 2006.

Zur Izhakian

In this paper we further develop the theory of matrices over the extended tropical semiring. Introducing a notion of tropical linear dependence allows for a natural definition of matrix rank in a sense that coincides with the notions of tropical regularity and invertibility.

Adam Rycerz, Jozef Spalek

The zero-temperature conductance of diatomic molecule, modelled as a correlated double quantum dot attached to noninteracting leads is investigated. We utilize the Rejec-Ramsak formulas, relating the linear-response conductance to the ground-state energy dependence on magnetic flux within the framework of EDABI method, which combines exact diagonalization wi

Kurosh Javidan

By including potential into the flat metric, we study interaction of sine-Gordon soliton with potentials. We will show numerically that while the soliton-barrier system shows fully classical behaviour, the soliton-well system demonstrates non-classical behaviour. In particular, solitons with low velocities are trapped in the well and emit energy radiation.

Prasanta Mahato

In the gravity without metric formalism of Capovilla, Jacobson and Dell, the topological $θ$-term appears through a canonical transformation.The origin of this canonical transformation is probed here. It is shown here that when $θ$-term appears cosmological $λ$-term also appears simultaneously.

N. P. Andreeva, D. A. Artemenkov, V. Bradnova, M. M. Chernyavsky

The relativistic invariant approach is applied to analyzing the 3.3 A GeV $^{22}$Ne fragmentation in a nuclear track emulsion. New results on few-body dissociations have been obtained from the emulsion exposures to 2.1 A GeV $^{14}$N and 1.2 A GeV $^{9}$Be nuclei. It can be asserted that the use of the invariant approach is an effective means of obtaining co

P. H. Chavanis

Systems with long-range interactions can reach a Quasi Stationary State (QSS) as a result of a violent collisionless relaxation. If the system mixes well (ergodicity), the QSS can be predicted by the statistical theory of Lynden-Bell (1967) based on the Vlasov equation. When the initial distribution takes only two values, the Lynden-Bell distribution is simi

Henning Krause

Given an abelian length category A, the Gabriel-Roiter measure with respect to a length function l is characterized as a universal morphism ind(A)-->P of partially ordered sets. The map is defined on the isomorphism classes of indecomposable objects of A and is a suitable refinement of the length function l.

K. Ikado

We present the first evidence of the decay B- --> tau- nu_tau-bar using 414 fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including sys

Vlada Limic, Pierre Tarrès

The goal is to show that an edge-reinforced random walk on a graph of bounded degree, with reinforcement weight function $W$ taken from a general class of reciprocally summable reinforcement weight functions, traverses a random attracting edge at all large times. The statement of the main theorem is very close to settling a conjecture of Sellke [Technical Re

Pietro Massignan, Yvan Castin

The possibility of using ultracold atoms to observe strong localization of matter waves is now the subject of a great interest, as undesirable decoherence and interactions can be made negligible in these systems. It was proposed that a static disordered potential can be realized by trapping atoms of a given species in randomly chosen sites of a deep 3D optic

S. D. Kaim

Analyzing the first equation in the BBGKY chain of equations for an equilibrium liquid-gas system, we derived the analytical expression for the atom work function from liquid into gas. The coupling between the atom work function from liquid into vacuum and the stability criterion of liquid in limiting points of the first type was shown (using I.Z. Fisher cla

Ashok Palaniappan

An intense controversy has surrounded the mechanism of voltage-gating in ion channels. We interpreted the two leading models of voltage-gating with respect to the thermodynamic energetics of membrane insertion of the voltage-sensing &#39;module&#39; from a comprehensive set of potassium channels. KvAP is an archaeal voltage-gated potassium channel whose x-ra

C. F. Huang, K. -N. Huang

A quantum master equation is obtained for identical fermions by including a relaxation term in addition to the mean-field Hamiltonian. [Huang C F and Huang K N 2004 Chinese J. Phys. ${\bf 42}$ 221; Gebauer R and Car R 2004 Phys. Rev. B ${\bf 70}$ 125324] It is proven in this paper that both the positivity and Pauli&#39;s exclusion principle are preserved und

Masahito Hayashi

We formulate two types of extensions of the large deviation theory initiated by Bahadur in a non-regular setting. One can be regarded as a bound of the point estimation, the other can be regarded as the limit of a bound of the interval estimation. Both coincide in the regular case, but do not necessarily coincide in a non-regular case. Using the limits of re

David Eppstein

We provide efficient constant factor approximation algorithms for the problems of finding a hierarchical clustering of a point set in any metric space, minimizing the sum of minimimum spanning tree lengths within each cluster, and in the hyperbolic or Euclidean planes, minimizing the sum of cluster perimeters. Our algorithms for the hyperbolic and Euclidean

A. M. Fedotov, Yu. E. Lozovik, N. B. Narozhny, A. N. Petrosyan

We consider particle creation (the Dynamical Casimir effect) in a uniformly contracting ideal one-dimensional cavity non-perturbatively. The exact expression for the energy spectrum of created particles is obtained and its dependence on parameters of the problem is discussed. Unexpectedly, the number of created particles depends on the duration of the cavity

Alexander V. Mitin

An analysis of the analytical solution of the Schrödinger equation (which is a second order differential equation) for $H_2^+$ shows that the second linear independent solution of this equation is a square integrable function and therefore the ground state total wave function is a linear combination of two linear independent wave functions of different space

Roger Ellman

It is well known and well established by scientific observation that a free neutron radioactively decays into a proton plus an electron plus an anti-neutrino with a mean life time before decay of about 900 seconds. That established fact conflicts sharply with the hypothesis that the neutron is composed of two down plus one up quark and that the proton is com

H. C. G. Caldas, P. R. Silva

From the hypothesis of a quadratic dependence of the binding energy of the quarks on the length scale and from the idea of a universal running coupling constant, we get the closure mass of the Universe and the pion mass. Besides this, we propose a free energy for the pions which stationarity condition leads to a closed form for the pion mass as a function of

Alexander Figotin, François Germinet, Abel Klein, Peter Müller

We show persistence of both Anderson and dynamical localization in Schrödinger operators with non-positive (attractive) random decaying potential. We consider an Anderson-type Schrödinger operator with a non-positive ergodic random potential, and multiply the random potential by a decaying envelope function. If the envelope function decays slower than $|x|^{

Sasa Kresic-Juric

A geometrical description of the Heisenberg magnet (HM) equation with classical spins is given in terms of flows on the quotient space $G/H_+$ where $G$ is an infinite dimensional Lie group and $H_+$ is a subgroup of $G$. It is shown that the HM flows are induced by an action of $\mathbb{R}^2$ on $G/H_+$, and that the HM equation can be integrated by solving

Emmanuel Amiot

This paper, in french, gives a new approach to the concept of Maximally Even Sets based on discrete Fourier transform, with several elementary but interesting and previously unpublished results. Maximally Even Sets have been invented by musicologists but have been found to bear deep relationships to other areas of science, such as the Ising model in Physics.

Ljudmila A. Bordag

The studied model was suggested to design a perfect hedging strategy for a large trader. In this case the implementation of a hedging strategy affects the price of the underlying security. The feedback-effect leads to a nonlinear version of the Black-Scholes partial differential equation. Using the Lie group theory we reduce the partial differential equation

A. D. Myasnikov, R. M Haralick

The Whitehead Minimization problem is a problem of finding elements of the minimal length in the automorphic orbit of a given element of a free group. The classical algorithm of Whitehead that solves the problem depends exponentially on the group rank. Moreover, it can be easily shown that exponential blowout occurs when a word of minimal length has been rea

Robert M. Haralick, Alexei D. Miasnikov, Alexei G. Myasnikov

We review some basic methodologies from pattern recognition that can be applied to helping solve combinatorial problems in free group theory. We illustrate how this works with recognizing Whitehead minimal words in free groups of rank 2. The methodologies reviewed include how to form feature vectors, principal components, distance classifers, linear classifi

R. M. Haralick, A. D. Miasnikov, A. G. Myasnikov

In this paper we discuss several heuristic strategies which allow one to solve the Whitehead&#39;s minimization problem much faster (on most inputs) than the classical Whitehead algorithm. The mere fact that these strategies work in practice leads to several interesting mathematical conjectures. In particular, we conjecture that the length of most non-minima

Milan kunz

Ferrers graphs and tables of partitions are treated as vectors. Matrix operations are used for simple proofs of identities concerning partitions. Interpreting partitions as vectors gives a possibility to generalize partitions on negative numbers. Partitions are then tabulated into lattices and some properties of these lattices are studied. There appears a ne

Jean-Christophe Bourin

Matrix versions of some basic convexity inequalities are given. Further results on the same topic are proved in the recent papers on arxiv: 1. Hermitian operators and convex functions, 2. A concavity inequality for symmetric norms, 3. Eigenvalue inequalities for convex and log-convex functions (with Jaspal Singh AUJLA).

Nicolas Chevrot, Emmanuel Fricain, Dan Timotin

It is shown that a contraction on a Hilbert space is complex symmetric if and only if the values of its characteristic function are all symmetric with respect to a fixed conjugation. Applications are given to the description of complex symmetric contractions with defect indices equal to 2.

Nik Weaver

We survey the use of extra-set-theoretic hypotheses, mainly the continuum hypothesis, in the C*-algebra literature. The Calkin algebra emerges as a basic object of interest.

Jaya N. N. Iyer

In this note, we investigate the Chern classes of flat bundles in the arithmetic Deligne Cohomology, introduced by Green-Griffiths, Asakura-Saito. We show nontriviality of the Chern classes in some cases and the proof also indicates that generic flat bundles (in its moduli space) can be expected to have nontrivial classes, which is in contrast with some Gaus

Ulrich Derenthal, Yuri Tschinkel

We discuss Manin&#39;s conjecture concerning the distribution of rational points of bounded height on Del Pezzo surfaces, and its refinement by Peyre, and explain applications of universal torsors to counting problems. To illustrate the method, we provide a proof of Manin&#39;s conjecture for the unique split singular quartic Del Pezzo surface with a singula

Alessandro Berarducci

By recent work on some conjectures of Pillay, each definably compact group $G$ in a saturated o-minimal expansion of an ordered field has a normal ``infinitesimal subgroup&#39;&#39; $G^{00}$ such that the quotient $G/G^{00}$, equipped with the ``logic topology&#39;&#39;, is a compact (real) Lie group. Our first result is that the functor $G\mapsto G/G^{00}$

Anna de Mier

We give a correspondence between graphs with a given degree sequence and fillings of Ferrers diagrams by nonnegative integers with prescribed row and column sums. In this setting, k-crossings and k-nestings of the graph become occurrences of the identity and the antiidentity matrices in the filling. We use this to show the equality of the numbers of k-noncro

Nick E. Mavromatos, Sarben Sarkar

We discuss the theoretical possibility that the neutrino mass differences have part of their origin in the quantum-decoherence-inducing medium of space-time foam, which characterises some models of quantum gravity, in much the same way as the celebrated MSW effect, responsible for the contribution to mass differences when neutrinos pass through ordinary mate

H. Khosravi, M. Naseri, S. Rouhani, M. V. Takook

An explicit calculation of Casimir effect through an alternative approach of field quantization [1, 2], has been presented in this paper. In this method, the auxiliary negative norm states have been utilized, the modes of which do not interact with the physical states or real physical world. Naturally these modes cannot be affected by the physical boundary c

R. N. Mohan, Sanpei Kageyama, Moon Ho Lee, Gao Yang

The Mn-matrix was defined by Mohan [20] in which he has shown a method of constructing (1,-1)-matrices and studied some of their properties. The (1,-1)-matrices were constructed and studied by Cohn [5],Wang [33], Ehrlich [8] and Ehrlich and Zeller[9]. But in this paper, while giving some resemblances of this matrix with Hadamard matrix, and by naming it as M

Marcin Raczkowski, Raymond Fresard, Andrzej M. Oles

We investigate the electron density distribution and the stability of stripe phases in the realistic two-band model with hopping elements between e_g orbitals at Ni sites on the square lattice, and compare these results with those obtained for the doubly degenerate Hubbard model with two equivalent orbitals and diagonal hopping. For both models we determine

G. Ortiz, J. Dukelsky

Recently, the nature of Cooper pairs in the BCS-BEC crossover has regained attention due to the observation of a large fraction of preformed fermion pairs on the BCS side of the Feshbach resonance in ultracold atomic Fermi gases. While several theoretical explanations were proposed, the interpretations are still controversial. The root of the controversy is

R. Nath, T. El Goresy, H. Zimmermann, R. Bohmer

Supercooled liquid and glassy acetyl salicylic acid was studied using dielectric spectroscopy and deuteron relaxometry in a wide temperature range. The supercooled liquid is characterized by major deviations from thermally activated behavior. In the glass the secondary relaxation exhibits the typical features of a Johari-Goldstein process. Via measurements o

B. Abdollahipour, M. Zareyan

We develop a semiclassical Boltzmann-Langevin theory of the spin polarized shot noise in a diffusive normal metal spin-valve connected by tunnel contacts to ferromagnetic reservoirs with noncollinear magnetizations. We obtain basic equations for correlations of the fluctuating spin-charge distribution and current density matrices by taking into account the s

Yoav Tsori

We consider theoretically liquid rise against gravity in capillaries with height-dependent cross-section. For a conical capillary made from a hydrophobic surface and dipped in a liquid reservoir, the equilibrium liquid height depends on the cone opening angle $α$, the Young-Dupré contact angle $θ$, the cone radius at the reservoir&#39;s level $R_0$ and the c

R. K. Singh, R. Gandikota, J. Kim, N. Newman

MgB2 tunnel junctions (MgB2/barrier/MgB2) were fabricated using a native oxide grown on the bottom MgB2 film as the tunnel barrier. Such barriers therefore survive the deposition of the second electrode at 300oC, even over junction areas of ~1 mm2. Studies of such junctions, and those of the type MgB2/native or thermal oxide/metal (Pb, Au, or Ag) show that t

Oskar Vafek, Ashot Melikyan

We employ index theoretic methods to study analytically the low energy spectrum of a lattice d-wave superconductor in the vortex lattice state. This allows us to compare singly quantized $hc/2e$ and doubly quantized $hc/e$ vortices, the first of which must always be accompanied by $Z_2$ branch cuts. For an inversion symmetric vortex lattice and in the presen

B-C Koo, J-h Kang, C. J. Salter

Although some 20--30,000 supernova remnants (SNRs) are expected to exist in the Milky Way, only about 230 are presently known. This implies that most SNRs are ``missing&#39;&#39;. Recently, we proposed that small ($\simlt 1^\circ$), faint, high-velocity features seen in large-scale 21-cm line surveys of atomic hydrogen ({\sc Hi}) in the Galactic plane could

I. V. Khalzov, A. I. Smolyakov, V. I. Ilgisonis

The spectral stability of liquid metal differentially rotating in transverse magnetic field is studied numerically by solving the eigenvalue problem with rigid-wall boundary conditions. The equilibrium velocity profile used in calculations corresponds to the electrically driven flow in circular channel with the rotation law Ω(r)~1/r^2. This type of flow prof

Maxim Lyutikov

Sharp fronts observed by Chandra satellite between dense cool cluster cores moving with near-sonic velocity through the hotter intergalactic gas, require strong suppression of thermal conductivity across the boundary. This may be due to magnetic fields tangential to the contact surface separating two plasma components. We point out that a super-Alfvenic moti

A. Alexandrou Himonas, Gerard Misiołek, Gustavo Ponce, Yong Zhou

It is shown that a strong solution of the Camassa-Holm equation, initially decaying exponentially together with its spacial derivative, must be identically equal to zero if it also decays exponentially at a later time. In particular, a strong solution of the Cauchy problem with compact initial profile can not be compactly supported at any later time unless i

T. R. Govindarajan, Seckin Kurkcuoglu, Marco Panero

We study noncommutative field theories, which are inherently nonlocal, using a Poincaré-invariant regularisation scheme which yields an effective, nonlocal theory for energies below a cut-off scale. After discussing the general features and the peculiar advantages of this regularisation scheme for theories defined in noncommutative spaces, we focus our atten

Kenneth Pryor

The Geostationary Operational Environmental Satellite (GOES) sounder-derived Wet Microburst Severity Index (WMSI) was originally developed and implemented to assess the potential magnitude of convective downbursts over the central and eastern continental United States. The WMSI algorithm incorporates convective available potential energy (CAPE), to parameter

Michael K. -H. Kiessling

We discuss a class of quantum Abraham models in which the N-particle spinor wave function of N electrons solves a Pauli respectively Schroedinger equation, featuring regularized classical electromagnetic potentials which solve the semi-relativistic Maxwell-Lorentz equations for regularized point charges, which move according to some de Broglie-Bohm law of qu

P. Gandhi, A. C. Fabian, C. S. Crawford

We present new X-ray and optical spectroscopy of a Type 2 quasar candidate selected from a follow-up program of hard, optically-dim, serendipitous Chandra sources. The source is confirmed to be a Type 2 quasar at z=0.536 with an intrinsic 2-10 keV luminosity L_{2-10}=5x10^{44} h_{0.7}^{-2} erg/s, an absorbing column density N_H=8x10^{23} cm^{-2} and a neutra

Gabi Ben Simon

In this paper we find that the asymptotic nonlinear Maslov index defined on the universal cover of the group of all contact Hamiltonian diffeomorphisms of the standard 2n-1 dimensional contact sphere is a quasimorphism. Then we show our main result: Let M be standard n-1 complex projective space. We prove that the value of the pull back of the asymptotic non

Robert G. Leigh, Djordje Minic, Alexandr Yelnikov

We present details of the analytic computation of the spectrum of lowest spin glueballs in pure Yang-Mills theory in 2+1 dimensions. The new ingredient is provided by the conjectured new non-trivial expression for the (quasi)Gaussian part of the ground state wave-functional. We show that this wave-functional can be derived by solving the Schrodinger equation

Theo Buehler

We use bicombings on arcwise connected metric spaces to give definitions of convex sets and extremal points. These notions coincide with the customary ones in the classes of normed vector spaces and geodesic metric spaces which are convex in the usual sense. A rather straightforward modification of the standard proof of the Krein-Mil&#39;man Theorem yields t

Steven N. Evans, Yelena Shvets, Montgomery Slatkin

A forward diffusion equation describing the evolution of the allele frequency spectrum is presented. The influx of mutations is accounted for by imposing a suitable boundary condition. For a Wright-Fisher diffusion with or without selection and varying population size, the boundary condition is $\lim_{x \downarrow 0} x f(x,t)=θρ(t)$, where $f(\cdot,t)$ is th

C. J. Paley, S. N. Taraskin, S. R. Elliott

The spread in time of a mutation through a population is studied analytically and computationally in fully-connected networks and on spatial lattices. The time, t_*, for a favourable mutation to dominate scales with population size N as N^{(D+1)/D} in D-dimensional hypercubic lattices and as N ln N in fully-connected graphs. It is shown that the surface of t

Y. I. Ozhigov

We discuss the possibility to modify many-body Hilbert quantum formalism that is necessary for the representation of quantum systems dynamics. The notion of effective classical algorithm and visualization of quantum dynamics play the key role.

Carsten Gundlach, Jose M. Martin-Garcia

We prove that when the equations are restricted to the principal part the standard version of the BSSN formulation of the Einstein equations is equivalent to the NOR formulation for any gauge, and that the KST formulation is equivalent to NOR for a variety of gauges. We review a family of elliptic gauge conditions and the implicit parabolic and hyperbolic dr

Indranil Biswas, Norbert Hoffmann

Let C be a smooth projective curve of genus at least 2 over a field k. Given a line bundle L on C, we consider the moduli stack of rank 2n vector bundles E on C endowed with a nowhere degenerate symplectic form $b: E \otimes E \to L$ up to scalars. We prove that this stack is birational to BG_m times an affine space A^s if n and the degree of L are both odd

Francisco C. Alcaraz, Erel Levine, Vladimir Rittenberg

Using Monte-Carlo simulations on large lattices, we study the effects of changing the parameter $u$ (the ratio of the adsorption and desorption rates) of the raise and peel model. This is a nonlocal stochastic model of a fluctuating interface. We show that for $0<u<1$ the system is massive, for $u=1$ it is massless and conformal invariant. For $u>1$ the conf