December 2001 arXiv papers — page 17

Edward G. Timoshenko, Yuri A. Kuznetsov, Ronan Connolly

We present results of Monte Carlo study of the monomer-monomer correlation functions, static structure factor and asphericity characteristics of a single homopolymer in the coil and globular states for three distinct architectures of the chain: ring, open and star. To rationalise the results we introduce the dimensionless correlation functions rescaled via t

Yu. V. Nazarov, D. A. Bagrets

We propose a theory that treats the current, noise, and, generally, the full current statistics of electron transfer in a mesoscopic system in a unified, simple and efficient way. The theory appears to be a circuit theory of $2\times 2$ matrices associated with Keldysh Green functions. We illustrate the theory by considering the big fluctuations of currents

M. Bonitz, V. Golubnychiy, A. V. Filinov, Yu. E. Lozovik

Wigner crystallization in mesoscopic quantum dots containing only few ($N < 50$) electrons exhibits a number of interesting peculiarities: (i) there exist two distinct crystal phases, and (ii) the phase boundary sensitively depends on the precise particle number. In this paper we demonstrate that this behavior can be used to control the {\em collective} tran

F. V. Kyrychenko, J. Kossut

The valence band states confined in infinitely deep quantum dots made of diluted magnetic semiconductors (DMS) are considered theoretically. A complex anisotropic structure of the valence bands in DMSs with cubic symmetry described by the full Luttinger Hamiltonian is taken into account. It is found that the Zeeman splitting is very sensitive to the shape of

M. Kenzelmann, P. Santini

Exact diagonalization calculations of finite antiferromagnetic spin-1 Heisenberg chains at finite temperatures are presented and compared to a recent inelastic neutron scattering experiment for temperatures T up to 7.5 times the intrachain exchange constant J. The calculations show that the excitations at the antiferromagnetic point q=1 and at q=0.5 remain r

Joachim Mathiesen, Mogens H. Jensen

We show that the fractal growth described by the dielectric breakdown model exhibits a phase transition in the multifractal spectrum of the growth measure. The transition takes place because the tip-splitting of branches forms a fixed angle. This angle is eta dependent but it can be rescaled onto an ``effectively&#39;&#39; universal angle of the DLA branchin

I. Gomez, E. Diez, F. Dominguez-Adame, P. Orellana

We present a novel model to calculate vertical transport properties such as conductance and current in unintentionally disordered double barrier GaAs-Al$_x$Ga$_{1-x}$As heterostructures. The source of disorder comes from interface roughness at the heterojunctions (lateral disorder) as well as spatial inhomogeneities of the Al mole fraction in the barriers (c

A. Amann, J. Schlesner, A. Wacker, E. Schöll

We analyze the dynamical evolution of the current and the charge density in a superlattice for fixed external dc voltage in the regime of self-sustained current oscillations, using a microscopic sequential tunneling model. Fronts of accumulation and depletion layers which are generated at the emitter may collide and annihilate, thereby leading to a variety o

G. M. Chechin, A. V. Gnezdilov, M. Yu. Zekhtser

The special nonlinear dynamical regimes, &#34;bushes of normal modes&#34;, can exist in the N-particle Hamiltonian systems with discrete symmetry. The dimension of the bush can be essentially less than that of the whole mechanical system. One-dimensional bushes represent the similar nonlinear normal modes introduced by Rosenberg. A given bush can be excited

M. Mali, J. Roos, H. Keller, J. Karpinski

We report on high-precision measurements of the temperature dependence of the plane-^63Cu NQR line frequency nu_Q(Cu2) and the linewidth in normal and superconducting ^16O and ^18O exchanged YBa_2Cu_4O_8. Whereas nu_Q(Cu2) passes T_c very smoothly without a discontinuity either in value nor in slope, the linewidth increases in the normal conducting phase dow

I. N. Askerzade, A. Gencer, N. Guclu

Temperature dependence of the upper critical field Hc2 (T) for the superconducting magnesium diboride, MgB2, is studied in the vicinity of Tc by using a two-band Ginzburg-Landau (G-L) theory. The temperature dependence of Hc2 (T) near Tc exhibits a positive curvature. In addition, the calculated temperature dependence and its higher order derivatives are als

Shuuichi Ooi, Takashi Mochiku, Kazuto Hirata

To study the Josephson-vortex system in the intrinsic Josephson junctions, we have measured the flow resistance as a function of magnetic field parallel to the $ab$ plane in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+y}$ single crystals. Although it was known that the flow resistance increases smoothly with increasing field, we have found novel oscillations of vortex

Indranil Rudra, C. Raghu, S. Ramasesha

We have used a many-body model Hamiltonian to study the nature of the magnetic ground state of hetero-binuclear complexes involving rare-earth and copper ions. We have taken into account all diagonal repulsions involving the rare-earth 4f and 5d orbitals and the copper 3d orbital. Besides, we have included direct exchange interaction, crystal field splitting

Luca Capriotti

We investigate the interplay between frustration and zero-point quantum fluctuations in the ground state of the triangular and $J_1{-}J_2$ Heisenberg antiferromagnets, using finite-size spin-wave theory, exact diagonalization, and quantum Monte Carlo methods. In the triangular Heisenberg antiferromagnet, by performing a systematic size-scaling analysis, we h

Luca Capriotti, Federico Becca

The ground state of an array of coupled, spin-half, antiferromagnetic ladders is studied using spin-wave theory, exact diagonalization (up to 36 sites) and quantum Monte Carlo techniques (up to 256 sites). Our results clearly indicate the occurrence of a zero-temperature phase transition between a Néel ordered and a non-magnetic phase at a finite value of th

M. Bologna, P. Grigolini, B. J. West

We study a process of anomalous diffusion, based on intermittent velocity fluctuations, and we show that its scaling depends on whether we observe the motion of many independent trajectories or that of a Liouville-like equation driven density. The reason for this discrepancy seems to be that the Liouville-like equation is unable to reproduce the multi-scalin

P. Vonlanthen, K. B. Tanaka, Atsushi Goto, W. G. Clark

We report $^{7}$Li pulsed NMR measurements in polycrystalline and single crystal samples of the quasi one-dimensional S=1 antiferromagnet LiVGe$_2$O$_6$, whose AF transition temperature is $T_{\text{N}}\simeq 24.5$ K. The field ($B_0$) and temperature ($T$) ranges covered were 9-44.5 T and 1.7-300 K respectively. The measurements included NMR spectra, the sp

Peter Van

The variational approach to weakly nonlocal thermodynamic theories is critically revisited in the light of modern nonequilibrium thermodynamics. The example of Ginzburg-Landau equation is investigated in detail.

M. A. Cirone, K. Goral, K. Rzazewski, M. Wilkens

We investigate the notion of Bose-Einstein condensation of interacting particles. The definition of the condensate is based on the existence of the dominant eigenvalue of the single-particle density matrix. The statistical properties and the characteristic temperature are computed exactly in the soluble models of two interacting atoms.

B. E. Wood, J. L. Linsky, G. Hebrard, A. Vidal-Madjar

We use Far Ultraviolet Spectrocopic Explorer (FUSE) observations to study interstellar absorption along the line of sight to the white dwarf WD1634-573 (d=37.1+/-2.6 pc). Combining our measurement of D I with a measurement of H I from Extreme Ultraviolet Explorer data, we find a D/H ratio toward WD1634-573 of D/H=(1.6+/-0.5)e-5. In contrast, multiplying our

Guillermo Torres, Ralph Neuhaeuser, Eike W. Guenther

We report the results of our radial-velocity monitoring of spectroscopic binary systems in a sample of X-ray sources from the ROSAT All Sky Survey south of the Taurus-Auriga star-forming region. The original sample of approximately 120 sources by Neuhaeuser et al. was selected on the basis of their X-ray properties and the visual magnitude of the nearest opt

A. Comastri, C. Vignali, M. Brusa

Multiwavelength observations of the hard X-ray selected sources discovered by BeppoSAX, Chandra and XMM-Newton surveys have significantly improved our knowledge of the AGN population. The increasing number of X-ray obscured AGN so far discovered confirms the prediction of those AGN synthesis models for the X-ray background based on the Unified scheme. Howeve

John Feldmeier, Chris Mihos, Patrick Durrell, Robin Ciardullo

The galaxy pair NGC 5194/95 (M 51) is one of the closest and best known interacting systems. Despite its notoriety, however, many of its features are not well studied. Extending westward from NGC 5195 is a low surface brightness tidal tail, which can only be seen in deep broadband exposures. Our previous [O III] lambda 5007 planetary nebulae (PN) survey of M

D. J. Wilner, M. C. H. Wright, J. Di Francesco

We report upper limits on CO J=2--1 and CO J=5--4 emission from the quasar SDSSp J104433.04-012502.2 at z=5.73 from observations made with the Berkeley-Illinois-Maryland-Association Array. Previously reported limits on CO J=6--5 emission (Iwata et al. 2001) were obtained at z=5.80, which is now thought to be off by 1%, and the observations likely missed the

S. Cristiani, S. Bianchi, S. D&#39;Odorico, T. -S. Kim

The remarkable efficiency of the UVES spectrograph at the VLT has made it possible to push high-resolution, high-S/N ground observations of the Ly-a forest down to z~1.5, gaining new insight into the physical conditions of the intergalactic medium and its evolution over more than 90% of the cosmic time. The universal expansion, the UV ionizing background and

M. Cignoni, V. Castellani, S. Degl&#39;Innocenti, S. Petroni

On the basis of theoretical evolutionary expectations, we develop a Galactic model reproducing star counts and synthetic color-magnitude diagrams of field stars, which include the white dwarf (WD) population. In this way we are able to evaluate the expected occurrence of WDs in deep observations at the various photometric bands and Galactic coordinates, disc

Victor P. Debattista, Enrico Maria Corsini, J. A. L. Aguerri

We measured the bar pattern speed, $\om$, of the SB0 galaxy NGC 1023 using the Tremaine-Weinberg (1984) method with stellar-absorption slit spectroscopy. The morphology and kinematics of the \hi gas outside NGC 1023 suggest it suffered a tidal interaction, sometime in the past, with one of its dwarf companions. At present, however, the optical disc is relaxe

P. P. Plucinsky, R. K Smith, R. J. Edgar, T. J. Gaetz

We present results from two Chandra/ACIS observations of the so-called Vela ``Bullet D&#39;&#39; region on the eastern limb of the Vela supernova remnant. The Bullet D region is a bright X-ray feature, identified by Aschenbach et al. (1995) from the ROSAT All-Sky Survey, which protrudes beyond the blast wave on the eastern side of the remnant. It has been su

M. Magliocchetti

We use redshift determinations and spectral analysis of galaxies in the 2dF Galaxy Redshift Survey to study the properties of local radio sources with $S\ge 1$ mJy.

Jill M. Meyer, Kenneth H. Nordsieck, Jennifer L. Hoffman

We present visible-wavelength spectropolarimetric measurements of the emission-line star MWC 349A and its close optical companion MWC 349B, conducted with the HPOL spectropolarimeter on both the 0.9 m telescope at the University of Wisconsin&#39;s Pine Bluff Observatory and the 3.5 m WIYN telescope on Kitt Peak. Our measurements allow us to estimate the inte

Alison Sills, Tim Adams, Melvyn Davies, Matthew Bate

We performed high-resolution simulations of two stellar collisions relevant for stars in globular clusters. We considered one head-on collision and one off-axis collision between two 0.6 M_sun main sequence stars. We show that a resolution of about 100 000 particles is sufficient for most studies of the structure and evolution of blue stragglers. We demonstr

M. Tosi, L. Greggio, F. Annibali

We describe the approach adopted by our group to derive the star formation history (SFH) of the chosen LMC field, as part of the experiment to compare the predictions obtained by different groups with the synthetic Colour-Magnitude diagram method. We point out what are the evolutionary characteristics of the observed stellar populations, and present the SFH

J. S. B. Wyithe, E. Agol, E. L. Turner, R. W. Schmidt

Published parametric models of the Einstein Cross gravitational lens demonstrate that the image geometry can be reproduced by families of models. In particular, the slope of the mass-profile for the lens galaxy is unconstrained. However, recent models predict a dependence of image flux ratios on the slope of the mass profile. We use this dependence to constr

J. S. B. Wyithe, E. Agol, C. J. Fluke

We use published mid-IR and V-band flux ratios for images A and B of Q2237+0305 to demonstrate that the size of the mid-IR emission region has a scale comparable to or larger than the microlens Einstein Radius (ER, ~10^17 cm for solar mass stars). Q2237+0305 has been monitored extensively in the R and V-bands for ~15 years. The variability record shows signi

A. Akylas, I. Georgantopoulos, R. G. Griffiths, I. E. Papadakis

We analyze 37 RXTE observations of the type 2 Seyfert galaxy Mrk348 obtained during a period of 14 months. We confirm the spectral variability previous reported by Smith et al., in the sense that thecolumn density decreases by a factor of ~3 as the count rate increases. Column density variations could possibly originate either due to the random drift of clou

S. B. Popov, M. E. Prokhorov

We show, that different types of isolated neutron stars (INSs) show evidence in favor of magnetic field decay in these objects, and discuss how observations of INSs can help to constrain models of field decay.

Anthony D. Challinor, Daniel J. Mortlock, Floor van Leeuwen, Anthony N. Lasenby

Despite the fact that the physics of the cosmic microwave background anisotropies is most naturally expressed in Fourier space, pixelised maps are almost always used in the analysis and simulation of microwave data. A complementary approach is investigated here, in which maps are used only in the visualisation of the data, and the temperature anisotropies an

Floor van Leeuwen, Anthony D. Challinor, Daniel J. Mortlock, Mark A. J. Ashdown

We present a harmonic model for the data analysis of an all-sky cosmic microwave background survey, such as Planck, where the survey is obtained through ring-scans of the sky. In this model, resampling and pixelisation of the data are avoided. The spherical transforms of the sky at each frequency, in total intensity and polarization, as well as the bright-po

A. Boselli, J. Lequeux, G. Gavazzi

We present $^{12}$CO(J=1--0) line observations of 22 low-luminosity spiral galaxies in the Virgo cluster. These data, together with 244 others available in the literature, allow us to build a large sample that we use to study the molecular gas properties of galaxies spanning a large range of morphological types and luminosities and belonging to different env

Xiang-Ping Wu, Yan-Jie Xue

As an alternative explanation of the entropy excess and the steepening of the X-ray luminosity-temperature relation in groups and clusters, the galaxy formation-regulated gas evolution (GG) model proposed recently by Bryan makes an attempt to incorporate the formation of galaxies into the evolution of gas without additional heating by nongravitational proces

Taichi Kato, Seiichi Sakuma

The W Vir-type variable star, RU Cam, once claimed to have stopped pulsation, has been known to show irregularly variable amplitude. It has also shown from the analysis of the VSOLJ archive that visual observers of the VSOLJ have recorded the cessation of pulsation and its possible resumption, together with the phase of large-amplitude variation around 1910.

Dean M. Townsley, Lars Bildsten

Current evolutionary models imply that most Cataclysmic Variables (CVs) have P_orb<2 hours and are Dwarf Nova (DN) systems that are quiescent most of the time. Observations of nearby quiescent DN find that the UV spectrum is dominated by the hot white dwarf (WD), indicating that it provides a significant fraction of the optical light in addition to the quies

R. Morganti, T. A. Oosterloo, S. Tinti, C. N. Tadhunter

Large-scale (up to 100 kpc) HI structures have been found in three radio galaxies using the WSRT and the VLA. In one case, the HI has been detected in emission while in the other two HI absorption is detected against the radio lobes. In at least two of the three studied radio galaxies the HI appears to be distributed in a large disk and the large amount of n

M. Tosi, L. Greggio, F. Annibali, A. Aloisi

We describe the star formation histories of three late-type dwarfs located outside the Local Group: IZw18, NGC1569 and NGC1705. The results are based on the application of the method of synthetic colour-magnitude diagrams to deep HST photometric data. All the examined galaxies were already forming stars at the reached lookback time and show no evidence of lo

Dean M. Townsley, Lars Bildsten

In recent years several Dwarf Novae (DN) systems have been observed in quiescence, when the accretion rate is low and the WD photosphere can be directly detected. The WDs are observed to cool after the DN outburst from high effective temperatures to lower effective temperatures (T_eff) thought to be indicative of the thermal state of the deep interior of the

Kesao Takamizawa, Minoru Wakuda, Taichi Kato

We discovered major brightenings of the symbiotic variable AS 289 in 1984 and 1995. During the outburst phase in 1996, we detected a temporary drop of the brightness. We consider that an eclipse is responsible for the fading episode of AS 289 during outburst, as in FG Ser or V1413 Aql. The profile of light curve suggests the eclipse may be grazing total, whi

Kailash C. Sahu, Jay Anderson, Ivan R. King

We have carried out further analysis of the tentative, short-term brightenings reported by Sahu et al. (2001), which were suggested to be possible lensings of Galactic-bulge stars by free-floating planets in the globular cluster M22. Closer examination shows that--unlikely as it may seem--small, point-like cosmic rays had hit very close to the same star in b

Geraint F. Lewis, Chris Carilli, Padeli Papadopoulos, R. J. Ivison

The ultraluminous broad absorption line quasar APM08279+5255 is one of the most luminous systems known. Here, we present an analysis of its nuclear CO(1-0) emission. Its extended distribution suggests that the gravitational lens in this system is highly elliptical, probably a highly inclined disk. The quasar core, however, lies in the vicinity of naked cusp,

A. E. Shapley, C. C. Steidel, K. L. Adelberger, Max Pettini

We present the results of detailed studies of the astrophysical conditions in z~3 Lyman Break Galaxies (LBGs), placing particular emphasis on what is learned from LBG rest frame UV spectra. By drawing from our database of ~1000 spectra, and constructing higher S/N composite spectra from galaxies grouped according to properties such as luminosity, extinction,

Olivia H. Billett, Deidre A. Hunter, Bruce G. Elmegreen

Nearby dwarf irregular galaxies were searched for compact star clusters using data from the HST archives. Three of the galaxies were found to host both populous clusters (M_V<-9.5 at a fiducial age of 10 Myr) and super-star clusters (M_V<-10.5 at 10 Myr). Four other dwarf galaxies, two of which contain populous and super-star clusters, were drawn from the li

C. H. Aboughantous

A nonsingular analytical solution for the transfer equation in a pure absorber is obtained in central symmetry and in a monochromatic radiation field. The native regular singularity of the equation is removed by applying a linear transformation to the frame of reference. Two different approaches are used to carry out the solution. In the first approach the a

D. Sanwal, G. G. Pavlov, O. Y. Kargaltsev, G. P. Garmire

We report the results of the spectral and timing analysis of observations of the Vela pulsar with the Chandra X-ray Observatory. The spectrum shows no statistically significant spectral lines in the observed 0.25--8.0 keV band. It consists of two distinct continuum components. The softer component can be modeled as either a magnetic hydrogen atmosphere spect

Dag Østvang

This is a survey of a new type of relativistic space-time framework; the so-called quasi-metric framework. The basic geometric structure underlying quasi-metric relativity is quasi-metric space-time; this is defined as a 4-dimensional differentiable manifold ${\cal N}$ equipped with two one-parameter families ${\bf {\bar g}}_t$ and ${\bf g}_t$ of Lorentzian

Eli Michael, Svetozar Zhekov, Richard McCray, Una Hwang

We discuss the X-ray emission observed from Supernova Remnant 1987A with the Chandra X-ray Observatory. We analyze a high resolution spectrum obtained in 1999 October with the high energy transmission grating (HETG). From this spectrum we measure the strengths and an average profile of the observed X-ray lines. We also analyze a high signal-to-noise ratio CC

D. V. Khveshchenko

We develop a unified approach to both infrared and ultraviolet asymptotics of the fermion Green functions in the condensed matter systems that allow for an effective description in the framework of the Quantum Electrodynamics. By applying a path integral representation to the previously suggested form of the physical electron propagator we demonstrate that i

S. C. Gallagher, W. N. Brandt, G. Chartas, G. P. Garmire

With 40 ks of Chandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and Broad Absorption Line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard with the majority o

Gerald Cecil, Michael A. Dopita, Brent Groves, Andrew S. Wilson

Using the HST STIS spectrograph we have obtained a grid of [O III] and H-beta emission-line spectra at 0&#34;05x0&#34;19 and 60 km/s (FWHM) resolution that covers much of the NLR of NGC 1068. We find emitting knots that have blueshifted radial velocities up to 3200 km/s relative to galaxy systemic, are 70-150 pc NE of the nucleus and up to 40 pc from the rad

Philip A. Stone, Fabian Waleffe, Michael D. Graham

Nontrivial steady flows have recently been found that capture the main structures of the turbulent buffer layer. We study the effects of polymer addition on these &#34;exact coherent states&#34; (ECS) in plane Couette flow. Despite the simplicity of the ECS flows, these effects closely mirror those observed experimentally: Structures shift to larger length s

Shinsei Ryu, Yasuhiro Hatsugai

A criterion to determine the existence of zero-energy edge states is discussed for a class of particle-hole symmetric Hamiltonians. A ``loop&#39;&#39; in a parameter space is assigned for each one-dimensional bulk Hamiltonian, and its topological properties, combined with the chiral symmetry, play an essential role. It provides a unified framework to discuss

Mark Van Raamsdonk

We derive leading terms in the effective actions describing the coupling of bulk supergravity fields to systems of arbitrary numbers of Dp-branes and D(p+4)-branes in type IIA/IIB string theory. We use these actions to investigate the physics of Dp-D(p+4) systems in the presence of weak background fields. In particular, we construct various solutions describ

A. Nichols

We investigate the W-algebras generated by the integer dimension chiral primary operators of the SU(2)_0 WZNW model. These have a form almost identical to that found in the c=-2 model but have, in addition, an extended Kac-Moody structure. Moreover on Hamiltonian reduction these SU(2)_0 W-algebras exactly reduce to those found in c=-2. We explicitly find the

Edi Halyo

We derive the Cardy--Verlinde entropy formula for the field theory that lives on the boundary of an asymptotically de Sitter space with a black hole. The boundary theory which is not conformal has a monotonic $C$--function defined by the Casimir energy. The instability of the space due to Hawking radiation from the black hole corresponds to an RG flow from t

J. M. Gracia-Bondia, F. Lizzi, G. Marmo, P. Vitale

While there has been growing interest for noncommutative spaces in recent times, most examples have been based on the simplest noncommutative algebra: [x_i,x_j]=i theta_{ij}. Here we present new classes of (non-formal) deformed products associated to linear Lie algebras of the kind [x_i,x_j]=ic_{ij}^k x_k. For all possible three-dimensional cases, we define

Gian F. Giudice, Riccardo Rattazzi, James D. Wells

Elastic collisions in the transplanckian region, where the center-of-mass energy is much larger than the fundamental gravity mass scale, can be described by linearized general relativity and known quantum-mechanical effects as long as the momentum transfer of the process is sufficiently small. For larger momentum transfer, non-linear gravitational effects be

A. Banfi, G. P. Salam, G. Zanderighi

For many event-shape observables, the most difficult part of a resummation in the Born limit is the analytical treatment of the observable&#39;s dependence on multiple emissions, which is required at single logarithmic accuracy. We present a general numerical method, suitable for a large class of event shapes, which allows the resummation specifically of the

M. Ave, J. Knapp, J. Lloyd-Evans, M. Marchesini

Air showers recorded by the Haverah Park Array during the years 1974 - 1987 have been re-analysed. For the original estimate of the energy spectrum, a relationship between the ground parameter $ρ$(600) and the primary energy, as determined by Hillas in the 1970s, was used. Here we describe the energy spectrum obtained using the QGSJET98 interaction model in

Andrei Gruzinov

It was suggested that observations of the solar system exclude massive gravity, in the sense that the graviton mass must be rigorously zero. This is because there is a discontinuity in the linearized gravity theory at graviton mass equal to zero. The linearized Schwarzschild metric is not recovered for infinitesimal graviton mass, contradicting observations

Cenalo Vaz, Louis Witten, T. P. Singh

Spherically symmetric, null dust clouds, like their time-like counterparts, may collapse classically into black holes or naked singularities depending on their initial conditions. We consider the Hamiltonian dynamics of the collapse of an arbitrary distribution of null dust, expressed in terms of the physical radius, $R$, the null coordinates, $V$ for a coll

Joao Magueijo, Lee Smolin

We propose a modification of special relativity in which a physical energy, which may be the Planck energy, joins the speed of light as an invariant, in spite of a complete relativity of inertial frames and agreement with Einstein&#39;s theory at low energies. This is accomplished by a non-linear modification of the action of the Lorentz group on momentum sp

H. Minakata, H. Nunokawa, R. Tomas, J. W. F. Valle

We point out that solar neutrino oscillations with large mixing angle as evidenced in current solar neutrino data have a strong impact on strategies for diagnosing collapse-driven supernova (SN) through neutrino observations. Such oscillations induce a significant deformation of the energy spectra of neutrinos, thereby allowing us to obtain otherwise inacces

Stefano Lepri, Roberto Livi, Antonio Politi

Deriving macroscopic phenomenological laws of irreversible thermodynamics from simple microscopic models is one of the tasks of non-equilibrium statistical mechanics. We consider stationary energy transport in crystals with reference to simple mathematical models consisting of coupled oscillators on a lattice. The role of lattice dimensionality on the breakd

A. V. Sologubenko, J. Jun, S. M. Kazakov, J. Karpinski

The bulk upper critical field H_{c2}(T) of superconducting MgB_2 and its anisotropy are established by analyzing experimental data on the temperature and magnetic field dependences of the ab-plane thermal conductivity of a single-crystalline sample in external magnetic fields oriented both parallel (H_{c2}^c) and perpendicular (H_{c2}^{ab}) to the c axis of

Jens Eisert, Christoph Simon, Martin B. Plenio

We investigate entanglement measures in the infinite-dimensional regime. First, we discuss the peculiarities that may occur if the Hilbert space of a bi-partite system is infinite-dimensional, most notably the fact that the set of states with infinite entropy of entanglement is trace-norm dense in state space, implying that in any neighborhood of every produ

Dermot McPeake, Halvor Moll Nilsen, J. F. McCann

A time-dependent method for calculating the collective excitation frequencies and densities of a trapped, inhomogeneous Bose-Einstein condensate with circulation is presented. The results are compared with time-independent solutions of the Bogoliubov-deGennes equations. The method is based on time-dependent linear-response theory combined with spectral analy

S. Huegle, R. Egger

We present a theory for the van Hove singularity (VHS) in the tunneling density of states (TDOS) of disordered multichannel quantum wires, in particular multi-wall carbon nanotubes. We assume close-by gates which screen off electron-electron interactions. Diagrammatic perturbation theory within a non-crossing approximation yields analytical expressions gover

H. Falomir, P. A. G. Pisani, A. Wipf

We study the pole structure of the $ζ$-function associated to the Hamiltonian $H$ of a quantum mechanical particle living in the half-line $\mathbf{R}^+$, subject to the singular potential $g x^{-2}+x^2$. We show that $H$ admits nontrivial self-adjoint extensions (SAE) in a given range of values of the parameter $g$. The $ζ$-functions of these operators pres

B. -J. Schaefer, O. Bohr, J. Wambach

Within a self-consistent proper-time Renormalization Group (RG) approach we investigate an effective QCD trace anomaly realization with dilatons and determine the finite-temperature behavior of the gluon condensate. Fixing the effective model at vanishing temperature to the glueball mass and the bag constant a possible gluonic phase transition is explored in

E. Bertin, J. -P. Bouchaud

We show that the trap model at its critical temperature presents dynamical ultrametricity in the sense of Cugliandolo and Kurchan [CuKu94]. We use the explicit analytic solution of this model to discuss several issues that arise in the context of mean-field glassy dynamics, such as the scaling form of the correlation function, and the finite time (or finite

R. Mélin, K. Biljakovic, J. C. Lasjaunias, P. Monceau

We show that the dynamics of disordered charge density waves (CDWs) and spin density waves (SDWs) is a collective phenomenon. The very low temperature specific heat relaxation experiments are characterized by: (i) ``interrupted&#39;&#39; ageing (meaning that there is a maximal relaxation time); and (ii) a broad power-law spectrum of relaxation times which is

Z. Akdeniz, P. Vignolo, A. Minguzzi, M. P. Tosi

We use a semiclassical three-fluid model to analyze the conditions for spatial phase separation in a mixture of fermionic Li-6 and a (stable) Bose-Einstein condensate of Li-7 atoms under cylindrical harmonic confinement, both at zero and finite temperature. We show that with the parameters of the Paris experiment [F. Schrek et al., Phys. Rev. Lett. 87 080403

M. Battaglia, A. Ferrari, A. Kiiskinen, Tuula Maki

In this paper, the pair production of charged Higgs bosons at possible future e+e- linear colliders is studied. Multi-jet final states are considered and the combinatorial, hadronic and genuine tbtb backgrounds are reduced thanks to a kinematical fit. TeV-class and multi-TeV linear colliders are likely to be sensitive to charged Higgs bosons with masses up t

Johann Rafelski, Jean Letessier

We study the canonical flavor enhancement arising from exact conservation of strangeness, and charm flavor. Both the theoretical motivation, and the practical consequences are explored. We argue using qualitative theoretical arguments and quantitative evaluation, that this proposal to reevaluate strangeness signature of quark--gluon plasma is not able to exp

Chun-Khiang Chua, Wei-Shu Hou, Kwei-Chou Yang

The color-suppressed \bar B^0-> D^{(*)0}π^0, D^{(*)0}η, D^0ωdecay modes have just been observed for the first time. The rates are all larger than expected, hinting at the presence of final state interactions. Considering \bar B^0-> D^{(*)0}π^0 mode alone, an elastic D^{(*)}π-> D^{(*)}πrescattering phase difference δ\equiv δ_{1/2} - δ_{3/2} \sim 30^\circ woul

L. T. Handoko, C. S. Kim, T. Yoshikawa

Longitudinal lepton polarization asymmetry in B_q -> l l (q = d, s$ and l = e, mu, tau) decays is investigated. The analysis is done in a general manner by using the effective operators approach. It is shown that the longitudinal lepton polarization asymmetry would provide a direct search for the scalar and pseudoscalar type interactions, which are induced i

Dan Tomino

We discuss the gravity dual description for a non-commutative Yang-Mills theory, which reduces to that on AdS_{5} x S_{5} in the commutative limit. It is found that doubletons do not decouple in this dual gravity description unless one takes the commutative limit. The decoupling of the doubletons in AdS_{5} space implies that the dual gauge theory has SU(N)

Bao-Xi Sun, Xiao-Fu Lü, En-Guang Zhao

Considering the finite volume of nucleons, a Lagrangian density is given. The first order self-energy of the nucleon and the equation of state of nuclear matter are calculated in the framework of relativistic mean-field approximation. Our results indicate the effects of the volume of nucleons are not negligible.

Kirk B. W. Buckley

It was recently shown that there exists metastable U(1)_A domain wall configurations in high-density QCD (μ>> 1 GeV). In the following we will assess the stability of such non-trivial field configurations at intermediate densities (μ< 1 GeV). The existence of such configurations at intermediate densities could have interesting consequences for the physics of

Carl E. Carlson, Christopher D. Carone

Experimental limits on the violation of four-dimensional Lorentz invariance imply that noncommutativity among ordinary spacetime dimensions must be small. Noncommutativity among extra, compactified spatial dimensions, however, is far less constrained and may have discernable collider signatures. Here we study the experimental consequences of noncommutative Q

Peter A. Storm

Closed hyperbolic manifolds are proven to minimize volume over all Alexandrov spaces with curvature bounded below by -1 in the same bilipschitz class. As a corollary compact convex cores with totally geodesic boundary are proven to minimize volume over all hyperbolic manifolds in the same bilipschitz class. Also, closed hyperbolic manifolds minimize volume o

Cosmin Macesanu

We present a computation of QCD next-to-leading order virtual corrections to the top production and decay process at linear colliders. The top quarks are allowed to be off-shell and the production and decay subprocesses are treated together, thus allowing for interference effects. The framework employed for our computation is the double pole approximation (D

A. Nogga, H. Kamada, W. Gloeckle, B. R. Barrett

The Faddeev-Yakubovsky equations for the alpha-particle are solved. Accurate results are obtained for several modern NN interaction models, which include charge-symmetry breaking effects in the NN force, nucleon mass dependences as well as the Coulomb interaction. These models are augmented by three-nucleon forces of different types and adjusted to the 3N bi

Luigi Accardi, Kentaro Imafuku, Massimo Regoli

The physical meaning of the EPR--chameleon experiment proposed in AcRe00b,AcRe01a, in which the EPR correlations are reproduced by local, independent, deterministic choices is re-examined. In addition we extend the mathematical model of AcRe00b,AcRe01a by showing that the dynamics considered there is effectively the reduced dynamics of a fully reversible evo

Benjamin Rahn

Balanced truncation, a technique from robust control theory, is a systematic method for producing simple approximate models of complex linear systems. This technique may have significant applications in physics, particularly in the study of large classical and quantum systems. These notes summarize the concepts and results necessary to apply balanced truncat

A. F. Abouraddy, M. B. Nasr, B. E. A. Saleh, A. V. Sergienko

The visibilities of second-order (single-photon) and fourth-order (two-photon) interference have been observed in a Young&#39;s double-slit experiment using light generated by spontaneous parametric down-conversion and a photon-counting intensified CCD camera. Coherence and entanglement underlie one-and two-photon interference, respectively. As the effective

Mark P. Davidson

It is shown that the stochastic model of Fenyes and Nelson can be generalized in such a way that the diffusion constant of the Markov theory becomes a free parameter. This extra freedom allows one to identify quantum mechanics with a class of Markov processes with diffusion constants varying from zero to infinity.

J. Dovc, G. Milcinski, M. Plesko

We present our experiences in managing the development cycles of the control systems for ANKA and the ALMA Common Software. Our team consists practically only of undergraduate students. Stimulating and rewarding the students with cutting-edge technologies and travel to conferences like this and installation fieldwork are an important positive factor in raisi

M. Kadunc, I. Kriznar, M. Plesko, G. Tkacik

At least as much time is spent solving problems addressed by application support as with actual interaction with the control system, if it is not factored into separate libraries but is coded by each programmer time and time again. Our Java libraries, called Abeans, address these issues in a communication platform independent way. Abeans perform connection m

R. Krivec, V. B. Mandelzweig

The quasilinearization method (QLM) of solving nonlinear differential equations is applied to the quantum mechanics by casting the Schrödinger equation in the nonlinear Riccati form. The method, whose mathematical basis in physics was discussed recently by one of the present authors (VBM), approaches the solution of a nonlinear differential equation by appro

A. Chepurnov, I. Gribov, V. Shvedunov, F. Nedeoglo

Very compact 70 MeV pulse race-track microtron is under construction now. To acquire outputs of beam-current transformers on every orbit and pulses of high voltage and RF field a distributed multi-channel beam diagnostic system was developed. Each acquisition controller consists of four fast differential amplifiers and one DSP-based micro-controller with on-

N. Hosoda, T. Ohshima, T. Aoki, T. Asaka

The timing system of SPring-8 booster synchrotron generates various timing signals concerning beam injection, acceleration from 1 GeV to 8 GeV and ejection. We have improved the timing system of the synchrotron giving it better stability and flexibility. This improvement results the other merits of advanced operations, for example, storing electron beam in t