Research archive
arXiv papers from September 2001
The most recent 100 records published that month. Open any paper for its original abstract, citation metadata, related research, and reading tools.
Giuseppe Pareschi, Mihnea Popa
We introduce the notion of Mukai regularity (M-regularity) for coherent sheaves on abelian varieties. The definition is based on the Fourier-Mukai transform, and in a special case depending on the choice of a polarization it parallels and strenghtens the usual Castelnuovo-Mumford regularity. Mukai regularity has a large number of applications, ranging from b
A. Heger, S. E. Woosley, T. Rauscher, R. D. Hoffman
We present a nucleosynthesis calculation of a 25 solar mass star of solar composition that includes all relevant isotopes up to polonium. In particular, all stable isotopes and necessary nuclear reaction rates are covered. We follow the stellar evolution from hydrogen burning till iron core collapse and simulate the explosion using a ``piston'' approach. We
Marcus Spradlin, Andrew Strominger, Anastasia Volovich
These lectures present an elementary discussion of some background material relevant to the problem of de Sitter quantum gravity. The first two lectures discuss the classical geometry of de Sitter space and properties of quantum field theory on de Sitter space, especially the temperature and entropy of de Sitter space. The final lecture contains a pedagogica
Badis Ydri
Regularization of quantum field theories (QFT's) can be achieved by quantizing the underlying manifold (spacetime or spatial slice) thereby replacing it by a non-commutative matrix model or a ``fuzzy manifold'' . Such discretization by quantization is remarkably successful in preserving symmetries and topological features, and altogether overcoming the fermi
- A possible solution to the solar neutrino problem: Relativistic corrections to the Maxwellian velocity distributionphysics.gen-ph
Jian-Miin Liu
The relativistic corrections to the Maxwellian velocity distribution are needed for standard solar models. Relativistic equilibrium velocity distribution, if adopted in standard solar models, will lower solar neutrino fluxes and change solar neutrino energy spectra but keep solar sound speeds. It is possibly a solution to the solar neutrino problem.
- Inventing E-Regulation in the US, EU and East Asia: Conflicting Social Visions of the Internet & the Information Societycs.CY
Shalini Venturelli
This paper attempts to assess the international approach to Internet policy in the context of distinctive socio-political frameworks evolving in the US, the European Union (EU), and East Asia. The comparative review will develop a set of underlying structural models of the Information Society particular to each region, along with an analysis of their definin
Matthew D. Duez, Thomas W. Baumgarte, Stuart L. Shapiro, Masaru Shibata
We model the adiabatic inspiral of relativistic binary neutron stars in a quasi-equilibrium (QE) approximation, and compute the gravitational wavetrain from the late phase of the inspiral. We compare corotational and irrotational sequences and find a significant difference in the inspiral rate, which is almost entirely caused by differences in the binding en
Reza Abbaspur
Based on an argument for the noncommutativity of momenta in noncommutative directions, we arrive at a generalization of the ${\cal N}=1$ super $E^2$ algebra associated to the deformation of translations in a noncommutative Euclidean plane. The algebra is obtained using appropriate representaions of its generators on the space of superfields in a $D=2, {\cal
Henryk A. Pinnow, Kay Joerg Wiese
In this article we study the effect of a delta-interaction on a polymerized membrane of arbitrary internal dimension D. Depending on the dimensionality of membrane and embedding space, different physical scenarios are observed. We emphasize on the difference of polymers from membranes. For the latter, non-trivial contributions appear at the 2-loop level. We
Yu. F. Pirogov
The advantages to consider the ordinary space-time as the symplectic rather than pseudo-orthogonal one are indicated, and the consequences of extending this view to extra space/time dimensions are discussed.
Tsampikos Kottos, Uzy Smilansky, Joaquim Fortuny, Giuseppe Nesti
In this paper we analyze a recent experiment conducted in an anechoic chamber, where the scattering of microwaves from an array of metallic cylinders was measured. This is a system which displays chaotic scattering in the short wave limit. The analysis of the experimental data is aimed at elucidating the effects of the underlying chaos. We describe a robust
- High Resolution Observations of the Elliptical Galaxy NGC 4636 with the Reflection Grating Spectrometer On-Board XMM-Newtonastro-ph
H. Xu, S. M. Kahn, J. R. Peterson, E. Behar
We present the first high spectral resolution X-ray observation of the giant elliptical galaxy NGC 4636, obtained with the Reflection Grating Spectrometer on-board the XMM-Newton Observatory. The resulting spectrum contains a wealth of emission lines from various charge states of oxygen, neon, magnesium, and iron. Examination of the cross-dispersion profiles
Amnon Yekutieli, James J. Zhang
We prove that two-sided tilting complexes, and dualizing complexes, over simple Goldie rings (with some technical conditions) are always shifts of invertible bimodules. This allows us to describe the derived Picard groups of such rings, and to deduce these are Gorenstein (and sometimes even Auslander-Gorenstein Cohen-Macaulay) rings.
S. I. Bityukov, N. V. Krasnikov
We investigate squark and gluino pair production at LHC(CMS) for the case of nonuniversal gaugino masses. Visibility of signal by an excess over SM background in $(n \geq 2)jets + E^{miss}_T + (m \geq leptons)$ events depends rather strongly on the relation between LSP, gluino and squark masses and it decreases with the increase of LSP mass. For relatively h
Milan M. Cirkovic
We analyze the arguments allegedly supporting the so-called Self-Indication Assumption (SIA), as an attempt to reject counterintuitive consequences of the Doomsday Argument of Carter, Leslie, Gott and others. Several arguments purportedly supporting this assumption are demonstrated to be either flawed or, at best, inconclusive. Therefore, no compelling reaso
D. Blaschke, A. Gusev, V. Pervushin, D. Proskurin
We consider a conformal unified theory as the basis of conformal-invariant cosmological model where the permanent rigid state of the universe is compatible with the primordial element abundance and supernova data. We show that the cosmological creation of vector Z and W bosons, in this case, is sufficient to explain the CMB temperature (2.7 K). The primordia
K. Sasaki, J. Soffer, T. Uematsu
We investigate the positivity constraints for the structure functions of both virtual and real photon. From the Cauchy-Schwarz inequality we derive three positivity conditions for the general virtual photon case, which reduce, in the real photon case, to one condition relating the polarized and unpolarized structure functions.
Jacob D. Bekenstein
After reviewing the relation of entropy to information, I derive the entropy bound as applied to bounded weakly gravitating systems, and review the bound's applications to cosmology as well as its extensions to higher dimensions. I then discuss why black holes behave as 1-D objects when emitting entropy, which suggests that a black hole swallows information
Y. Aharonov, S. Massar, S. Popescu
Suppose that the Hamiltonian acting on a quantum system is unknown and one wants to determine what is the Hamiltonian. We show that in general this requires a time $\Delta t$ which obeys the uncertainty relation $\Delta t \Delta H \gtrsim 1$ where $\Delta H$ is a measure of how accurately the unknown Hamiltonian must be estimated. We then apply this result t
- Interaction of N solitons in the massive Thirring model and optical gap system: the Complex Toda Chain Modelnlin.SI
V. S. Shchesnovich
Using the Karpman-Solov''ev quasiparticle approach for soliton-soliton interaction I show that the train propagation of N well separated solitons of the massive Thirring model is described by the complex Toda chain with N nodes. For the optical gap system a generalised (non-integrable) complex Toda chain is derived for description of the train propagation of
Atsushi Senda, Hiroshi Murakami, Katsuji Koyama
We report the ASCA and Chandra discovery of a diffuse X-ray source in the Galactic center region. The X-ray spectrum is fitted with a non-equilibrium ionization (NEI) plasma model of about 6-keV temperature. The model requires higher than solar metal abundances, a young plasma age of $\simeq$ 100 years and a large N_H value of about 10^{23} cm^{-2}. The N_H
Kei-Ichi Kondo
We report an attempt of deriving a string representation of QCD based on a novel vacuum condensate of mass dimension 2.
- Vacuum condensate of mass dimension 2 as the origin of mass gap and quark confinement (A review)hep-ph
Kei-Ichi Kondo
This is a brief summary of recent works on the possibility of vacuum condensate of mass dimension 2 in Yang-Mills theory as the gluon sector of QCD. In particular, I discuss the physical implications due to this condensate, especially, for the mass gap and quark confinement. This talk is mainly based on a recent paper [1] and papers in preparation [2].
Thomas Kerler
We give an overview over several constructions of TQFT's over finite fields and cyclotomic integers and their applications to characterizing 3-manifolds and their fundamental groups.
Thomas Kerler
We construct families of TQFT's over the finite field Z/pZ starting from an integral TQFT obtained by Frohman and Nicas. These TQFT's are likely to describe the constant order contributions of the cyclotomic integer expansions of the Reshetikhin Turaev Ohtsuki theories. Their modular structure is intimately related to the p-modular representation theory of t
M. I. Dykman, B. Golding, L. I. McCann, V. N. Smelyanskiy
We discuss activated escape from a metastable state of a system driven by a time-periodic force. We show that the escape probabilities can be changed very strongly even by a comparatively weak force. In a broad parameter range, the activation energy of escape depends linearly on the force amplitude. This dependence is described by the logarithmic susceptibil
David Medvigy, Abraham Loeb
We consider element diffusion during the linear growth of structure in the intergalactic medium (IGM) before the redshift of reionization. The elements produced during big bang nucleosynthesis (such as D, He-4 or Li-7) condensed in collapsing regions more readily than hydrogen. Diffusion was most effective when the IGM was neutral since the collisional cross
Sergei I. Ipatov, Leonid M. Ozernoy
Trans-Neptunian objects (TNOs) with diameter greater than 100 km currently moving in not too eccentric orbits could be formed directly by the contraction of large rarefied condensations. Along with the gravitational influence of planets, gravitational interactions of TNOs played a certain role in their orbital evolution as well. More than 20% of Earth-crossi
R. Chary, E. E. Becklin, L. Armus
We present deep 2.2 micron imaging of twelve gamma-ray burst host galaxies. Template spectral energy distributions are fit to the multiband photometry between visible and near-infrared wavelengths to derive a better constraint on the stellar mass of these galaxies. The internal extinction in the host galaxies is estimated using the rest-frame ultraviolet (UV
D. Boyanovsky, H. J. de Vega
The perturbative approach to the description of long wavelength excitations at high temperature breaks down near the critical point of a second order phase transition. We study the \emph{dynamics} of these excitations in a relativistic scalar field theory at and near the critical point via a renormalization group approach at high temperature and an $\epsilon
Irina Mocioiu, Maxim Pospelov, Radu Roiban
A non-vanishing vacuum expectation value for an antisymmetric tensor field leads to the violation of Lorentz invariance, controlled by the dimension (-2) parameter, theta_{mu nu}. We assume that the zeroth order term in theta-expansion represents the Standard Model and study the effects induced by linear terms in theta_{mu nu}. If coupling to theta_{mu nu} i
T. A. S. Haddad, S. R. Salinas
We review and extend some recent investigations of the effects of aperiodic interactions on the critical behavior of ferromagnetic $q$-state Potts models. By considering suitable diamond or necklace hierarchical lattices, and assuming a distribution of interactions according to a class of two-letter substitution rules, the problem can be formulated in terms
Dae-Il Choi, Will Chism
We investigate the stabilization of a hydrogen atom in circularly polarized laser fields. We use a time-dependent, fully three dimensional approach to study the quantum dynamics of the hydrogen atom subject to high intensity, short wavelength laser pulses. We find enhanced survival probability as the field is increased under fixed envelope conditions. We als
Felipe Menanteau, Raul Jimenez, Francesca Matteucci
In this letter we address the problem of the origin of blue cores and inverse color gradients in early-type galaxies reported in the Hubble Deep Field North and South (HDFs) by Menanteau, Abraham & Ellis 2001. We use a multi-zone single collapse model. This model accounts for the observed blue cores by adopting a broad spread in formation redshifts for ellip
R. B. Nevzorov, K. A. Ter-Martirosyan, M. A. Trusov
The restrictions on the lightest Higgs boson mass in the minimal supersymmetric models are briefly reviewed. The particle spectrum is considered in the framework of the simplest modification of NMSSM that allows to avoid the domain wall problem and to get the self--consistent solution in the strong Yukawa coupling limit. The lightest Higgs boson mass in the
B. Pötter
I review the status of perturbative QCD calculations for jet production in eP-scattering at HERA. I will discuss possibilities of combining fixed order, especially higher order, calculations and parton showers.
D. M. Ghilencea
We investigate the proposed ``D-brane alternative'' to the MSSM model (DMSSM) which is a type II B string orientifold model with N=1 supersymmetry, three generations and a $SU(3)\times SU(2)_R\times SU(2)_L \times U(1)_{B-L}$ gauge group. An accurate analysis at two-loop level is performed to show that unification constraints predict a ``left-right'' symmetr
Emil T. Akhmedov
In this talk we show that the tachyon annihilation combined with an approximation, in which string theory non-commutativity structure is captured by the algebra of differential operators on space-time, gives a unified point of view on: non-Abelian structures on $D$-branes; all lowest energy excitations on $D$-branes; all RR couplings in type II string theory
- Determination of the Distance to M33 Based on the Tip of the Red Giant Branch and the Red Clumpastro-ph
Minsun Kim, Eunhyeuk Kim, Myung Gyoon Lee, Ata Sarajedini
We have determined the distance to M33 using the tip of the red giant branch (TRGB) and the red clump (RC), from the VI photometry of stars in ten regions of M33 based on HST/WFPC2 images. The regions used in this study are located at R=2.6 - 17.8 arcmin from the center of M33. The distance modulus to M33 obtained in this study, for an adopted foreground red
- Determination of the Distance to M33 Based on Single Epoch I-band HST Observations of Cepheidsastro-ph
Myung Gyoon Lee, Minsun Kim, Ata Sarajedini, Doug Geisler
We have determined the distance to M33 using single epoch I-band observations of Cepheids based on HST/WFPC2 images of five fields in M33. Combining the HST I-band photometry and the periods determined from the ground-based observations (DIRECT) for 21 Cepheids with log P>0.8 in the sample of 32 Cepheids, we derive a distance modulus of (m-M)_0=24.52+/-0.14(
W. Chen
The standard methodology handling nonlinear PDE's involves the two steps: numerical discretization to get a set of nonlinear algebraic equations, and then the application of the Newton iterative linearization or its variants to solve the nonlinear algebraic systems. Here we present an alternative strategy called direct linearization method (DLM). The DLM dis
- The failure of cosmological perturbation theory in the new ekpyrotic and cyclic ekpyrotic scenarioshep-ph
D H Lyth
Cosmological perturbation theory fails in the new ekpyrotic and cyclic ekpyrotic scenarios, before the scale factor of the Universe reaches zero. As a result, a recently-proposed recipe for evolving the curvature perturbation through the bounce in these scenarios cannot be justified.
P. Morel, G. Berthomieu, J. Provost, F. Thevenin
We have revisited the calibration of the visual binary system Zeta Herculis with the goal to give the seismological properties of the G0 IV sub-giant Zeta Her A. We have used the most recent physical and observational data. For the age we have obtained 3387 Myr, for the masses respectively 1.45 and 0.98 solar mass, for the initial helium mass fraction 0.243,
Victor Novozhilov, Yuri Novozhilov
We derive an effective colour chiral action with a background gauge field. The action describes configurations of soliton-skyrmion type. Kinetic term constant $f_0^2$, analogue of $f_\pi ^2$, is a phenomenological dimensional parameter of the model; $d=4$ terms are unique up to the choice of background gauge field. The case of SU(2) colour group is discussed
Daisuke Jido, Makoto Oka, Atsushi Hosaka
We study chiral symmetry aspects of the positive and negative parity baryons by identifying them with linear representations of the chiral group $SU(N_{f}) \otimes SU(N_{f})$. It is shown that there are two distinctive schemes: naive and mirror assignments. We construct linear sigma models for baryons in the two assignments and examine their physical implica
- The Supernova Remnant CTB104A : Magnetic Field Structure and Interaction with the Environmentastro-ph
Bulent Uyaniker, Roland Kothes, Cristopher M. Brunt
We present new, high resolution 1420 and 408 MHz continuum images and HI and 12CO (J=1-0) spectral line maps of the diffuse supernova remnant CTB104A (G93.7-0.3). Analysis of the complex continuum emission reveals no significant spectral index variations across the remnant. Three prominences around CTB104A are found to be related to the SNR, while one extens
L. Balents, M. P. A. Fisher, S. M. Girvin
We study an antiferromagnetic spin-1/2 model with up to third nearest-neighbor couplings on the Kagome lattice in the easy-axis limit, and show that its low-energy dynamics are governed by a four site XY ring exchange Hamiltonian. Simple ``vortex pairing'' arguments suggest that the model sustains a novel fractionalized phase, which we confirm by exactly sol
J. Gorosabel, M. I. Andersen, J. Hjorth, H. Pedersen
We report optical observations of the short/hard burst GRB 010119 error box, one of the smallest error boxes reported to date for short/hard GRBs. Limits of R > 22.3 and I > 21.2 are imposed by observations carried out 20.31 and 20.58 hours after the gamma-ray event, respectively. They represent the most constraining limits imposed to date on the optical emi
Arthur D. Chernin
Internal (non-geometric) symmetry is recognized and studied as a new phenomenon in cosmology. Symmetry relates cosmic vacuum to non-vacuum forms of cosmic energies, which are dark matter, baryons, and radiation. It is argued that the origin and physical nature of cosmic internal symmetry are due to the interplay between gravity and electroweak scale physics
A. M. Ghezelbash, R. B. Mann
We study the problem of vortex solutions in the background of rotating black holes in both asymptotically flat and asymptoticlly anti de Sitter spacetimes. We demonstrate the Abelian Higgs field equations in the background of four dimensional Kerr, Kerr-AdS and Reissner-Nordstrom-AdS black holes have vortex line solutions. These solutions, which have axial s
- Pairing Instability and Mechanical Collapse of a Bose Gas with an Attractive Interactioncond-mat.stat-mech
Gun Sang Jeon, Lan Yin, Sung Wu Rhee, David J. Thouless
We study the pairing instability and mechanical collapse of a dilute homogeneous bose gas with an attractive interaction. The pairing phase is found to be a saddle point, unstable against pairing fluctuations. This pairing saddle point exists above a critical temperature. Below this critical temperature, the system is totally unstable in the pairing channel.
Giuseppe Pareschi, Mihnea Popa
This paper is mainly concerned with applying the theory of M-regularity developed in the previous math.AG/0110003 to the study of linear series given by multiples of ample line bundles on abelian varieties. We define a new invariant of a line bundle, called M-regularity index, which is seen to govern the higher order properties and (partly conjecturally) the
H. Rosner, R. R. P. Singh, W. H. Zheng, J. Oitmaa
Exchange couplings are calculated for Li2VOSiO4 using LDA. While the sum of in-plane couplings J_1 + J_2 = 9.5 \pm 1.5 K and the inter-plane coupling J_{perp} \sim 0.2 - 0.3 K agree with recent experimental data, the ratio J_2/J_1 \sim 12 exceeds the reported value by an order of magnitude. Using geometrical considerations, high temperature expansions and pe
Carola F. Berger, Tibor Kucs, George Sterman
We study the distribution of transverse energy, Q_Omega, radiated into an arbitrary interjet angular region, Omega, in high-p_T two-jet events. Using an approximation that emphasizes radiation directly from the partons that undergo the hard scattering, we find a distribution that can be extrapolated smoothly to Q_Omega=Lambda_QCD, where it vanishes. This met
Yoji Yoshii
Quantum tori with graded involution appear as coordinate algebras of extended affine Lie algebras of type A_1, C and BC. We classify them in the category of algebras with involution. From this, we obtain precise information on the root systems of extended affine Lie algebras of type C.
C. N. Lau, N. Markovic, M. Bockrath, A. Bezryadin
We have measured the resistance vs. temperature of more than 20 superconducting nanowires with nominal widths ranging from 10 to 22 nm and lengths from 100 nm to 1050 nm. With decreasing cross-sectional areas, the wires display increasingly broad resistive transitions. The data are in very good agreement with a model that includes both thermally activated ph
Blake Mellor, Paul Melvin
Milnor's triple linking numbers of a link in the 3-sphere are interpreted geometrically in terms of the pattern of intersections of the Seifert surfaces of the components of the link. This generalizes the well known formula as an algebraic count of triple points when the pairwise linking numbers vanish.
Fernando da Rocha Vaz Bandeira de Melo, Robert H. Brandenberger, Adolfo Maia Junior
Parametric resonance has received a considerable amount of interest as a good mathematical model to describe the initial stages of the reheating phase (matter creation) in inflationary cosmology. It is also known that exponential particle creation can occur in situations which do not fall in the parametric resonance regime characterized by oscillations of th
Alexander Elgart, Jeffrey H. Schenker
We prove an adiabatic theorem for the evolution of spectral data under a weak additive perturbation in the context of a system without an intrinsic time scale. For continuous functions of the unperturbed Hamiltonian the convergence is in norm while for a larger class functions, including the spectral projections associated to embedded eigenvalues, the conver
Tommy Burch, Kostas Orginos, Doug Toussaint
Using lowest-order lattice NRQCD to create heavy meson propagators and applying the spin-dependent interaction, $c_B^{} \frac{-g}{2m_q}\vec\sigma\cdot\vec{B}$, at varying intermediate time slices, we compute the off-diagonal matrix element of the Hamiltonian for the quarkonium-hybrid two-state system. Diagonalizing this two-state Hamiltonian, the admixture o
Bi Qiao, Harry. E. Ruda, X. H. Zhen
Using the subdynamical kinetic equation for an open quantum system, a formulation is presented for performing decoherence-free (DF) quantum computing in Rigged Liouville Space (RLS). Three types of interactions were considered, and in each case, stationary and evolutionary states were evaluated for DF behavior in both the total space and the projected subspa
Shantilal G. Goradia
The gravitational inverse square law is microscopic approximation. I suggest that it should be modified for elementary particles to use the surface-to-surface separation of the particles rather than the center-to-center separations. For small particles at macroscopic separations, the ratio between the center-to-center distance D and the surface-to-surface di
Carmen Chicone
Action at a distance in Newtonian physics is replaced by finite propagation speeds in classical physics, the physics defined by the field theories of Maxwell and Einstein. As a result, the differential equations of motion in Newtonian physics are replaced in classical physics by functional differential equations, where the delay associated with the finite pr
Alexander Strohmaier
We introduce the notion of a semi-Riemannian spectral triple which generalizes the notion of spectral triple and allows for a treatment of semi-Riemannian manifolds within a noncommutative setting. It turns out that the relevant spaces in noncommutative semi-Riemannian geometry are not Hilbert spaces any more but Krein spaces, and Dirac operators are Krein-s
David H. Lyth, David Wands
We present a mechanism for the origin of the large-scale curvature perturbation in our Universe by the late decay of a massive scalar field, the curvaton. The curvaton is light during a period of cosmological inflation, when it acquires a perturbation with an almost scale-invariant spectrum. This corresponds initially to an isocurvature density perturbation,
K. L. Flores, V. Ramakrishna
We illustrate a technique for specifying piecewise constant controls for classes of switched electrical networks, typically used in converting power in a dc-dc converter. This procedure makes use of decompositions of SU(2) to obtain controls that are piecewise constant and can be constrained to be bang-bang with values 0 or 1. Complete results are presented
Helen Nissenbaum, Batya Friedman, Edward Felten
This paper focuses on a tension we discovered in the philosophical part of our multidisciplinary project on values in web-browser security. Our project draws on the methods and perspectives of empirical social science, computer science, and philosophy to identify values embodied in existing web-browser security and also to prescribe changes to existing syste
M. S. Berger, Kim Siyeon
We relate leptogenesis in a class of theories to low-energy experimental observables: quark and lepton masses and mixings. With reasonable assumptions motivated by grand unification, one can show that the CP-asymmetry parameter takes a universal form. Furthermore the dilution mass is related to the light neutrino masses. Overall, these models offer a natural
Tom Chou
Long-ranged electrostatic interactions in electrolytes modify their contact angles on charged substrates in a scale and geometry dependent manner. For angles measured at scales smaller than the typical Debye screening length, the wetting geometry near the contact line must be explicitly considered. Using variational and asymptotic methods, we derive new tran
- Exact Differential O(alpha**2) Results for Hard Bremsstrahlung in e+e- Annihilation to 2f At and Beyond LEP2 Energieshep-ph
S. Jadach, M. Melles, B. F. L. Ward, S. A. Yost
We present the exact O(alpha) correction to the process e+ e- -> f f-bar + gamma, f neq e, for ISR oplus FSR at and beyond LEP2 energies. We give explicit formulas for the completely differential cross section. As an important application, we compute the size of the respective sub-leading corrections of O(alpha L) to the f f-bar cross section, where L is the
A. Bill, V. Z. Kresin
Intercalation of polyatomic molecules into a superconductor can drastically affect the properties of the compound. A mechanism leading to a large increase in Tc for such systems is proposed. It explains the recent remarkable observation of high Tc superconductivity in the hole-doped C60/CHX3 (X=Cl,Br) compounds and the large shift in their Tc upon Cl->Br sub
Tod E. Strohmayer
X-ray observations suggest that neutron stars in low mass X-ray binaries (LMXB) are rotating with frequencies from 300 - 600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If
R. M. Serra, N. G. de Almeida, W. B. da Costa, M. H. Y. Moussa
We investigate the mechanism of damping and heating of trapped ions associated with the polarization of the residual background gas induced by the oscillating ions themselves. Reasoning by analogy with the physics of surface electrons in liquid helium, we demonstrate that the decay of Rabi oscillations observed in experiments on 9Be+ can be attributed to the
Denis Bernard, Andre' LeClair
We present a detailed classification of random Dirac hamiltonians in two spatial dimensions based on the implementation of discrete symmetries. Our classification is slightly finer than that of random matrices, and contains thirteen classes. We also extend this classification to non-hermitian hamiltonians with and without Dirac structure.
John M. Cannon, Evan D. Skillman, Donald R. Garnett, Reginald J. Dufour
We present new WFPC2 narrow band imaging of the blue compact dwarf galaxy I Zw 18, which is host to the lowest-metallicity HII regions known. Images at H-alpha and H-beta are combined with archival broad band images to allow the study of the ionized gas distribution and morphology. Analysis of the H-alpha/H-beta flux ratio reveals significant enhancements in
Vuko Brigljevic
We report measurements of charmonium resonances (J/Psi, Psi(2S),Chi_c1) using about 25 fb^-1 of data collected by the BABAR detector around the Upsilon(4S) resonance. We present measurements of inclusive charmonium production of charmonium in B decays and from the continuum, as well as exclusive branching ratios of B mesons into charmonium final states. We p
Egilberto Lombardi, Fabio Sciarrino, Sandu Popescu, Francesco De Martini
We report the experimental realization of teleporting an entangled qubit. The qubit is physically implemented by a two-dimensional subspace of states of a mode of the electromagnetic field, specifically, the space spanned by the vacuum and the one photon state. Our experiment follows along lines suggested by H. W. Lee and J. Kim, Phys. Rev. A, 63, 012305 (20
Thomas Vojta, Michael Schreiber
We consider the combined influence of disorder, electron-electron interactions and quantum hopping on the properties of electronic systems in a localized phase, approaching an insulator-metal transition. The generic models in this regime are the quantum Coulomb glass and its generalization to electrons with spin. After introducing these models we explain our
Daniel Zwanziger
We discuss Faddeev-Popov quantization at the non-perturbative level and show that Gribov's prescription of cutting off the functional integral at the Gribov horizon does not change the Schwinger-Dyson equations, but rather resolves an ambiguity in the solution of these equations. We note that Gribov's prescription is not exact, and we therefore turn to the m
Amer Iqbal, Amir-Kian Kashani-Poor
The integrality of Ooguri-Vafa disk invariants is verified using discrete symmetries of the superpotential of the mirror Landau-Ginzburg theory to calculate quantum corrections to the boundary variables. We show that these quantum corrections are completely determined if we assume that the discrete symmetry of the superpotential also holds in terms of the qu
G. Fiorentini, F. L. Villante, B. Ricci
The comparison of the SNO charged current result with the solar neutrino signal measured by Super-Kamiokande has provided, for the first time, the evidence of a non electron flavour active neutrino component in the solar flux. We remark here that this evidence can be obtained in a model independent way, i.e. without any assumpion about solar models, about th
Jijun Zhao, Jian Ping Lu
Different phases of solid boron under high pressure are studied by first principles calculations. The $\alpha$-B$_{12}$ structure is found to be stable up to 270 GPa. Its semiconductor band gap (1.72 eV) decreases continuously to zero around 160 GPa, where the material transforms to a weak metal. The metallicity, as measured by the density of states at the F
Ashok Das, Ziemowit Popowicz
We construct the N=1 supersymmetric extension of the polytropic gas dynamics. We give both the Lagrangian as well as the Hamiltonian description of this system. We construct the infinite set of "Eulerian'' conserved charges associated with this system and show that they are in involution, thereby proving complete integrability of this system. We construct th
Jonathan R. Friedman, D. V. Averin
We suggest a system in which the amplitude of macroscopic flux tunneling can be modulated via the Aharonov-Casher effect. The system is an rf-SQUID with the Josephson junction replaced by a Bloch transistor -- two junctions separated by a small superconducting island on which the charge can be induced by an external gate voltage. When the Josephson coupling
Ravi Sankrit, William P. Blair
We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of a Balmer filament in the northeast region of the Cygnus Loop supernova remnant. The data consist of one spectrum obtained through the 30"x30" (LWRS) aperture and three spectra at adjacent positions obtained through the 4"x20" (MDRS) aperture. The nonradiative shocks in the region giving
E. C. G. Sudarshan
It is often stated that quantum mechanics only makes statistical predictions and that a quantum state is described by the various probability distributions associated with it. Can we describe a quantum state completely in terms of probabilities and then use it to describe quantum dynamics? What is the origin of the probability distribution for a maximally sp
E. C. G. Sudarshan
The generic linear evolution of the density matrix of a system with a finite-dimensional state space is by stochastic maps which take a density matrix linearly into the set of density matrices. These dynamical stochastic maps form a linear convex set that may be viewed as supermatrices. The property of hermiticity of density matrices renders an associated su
H. O. Girotti, M. Gomes, A. Yu. Petrov, V. O. Rivelles
We study the superspace formulation of the noncommutative nonlinear supersymmetric O(N) invariant sigma-model in 2+1 dimensions. We prove that the model is renormalizable to all orders of 1/N and explicitly verify that the model is asymptotically free.
Elham Kashefi, Harumichi Nishimura, Vlatko Vedral
We discuss the question of the existence of quantum one-way permutations. First, we prove the equivalence between inverting a permutation and that of constructing a polynomial size network for reflecting about a given quantum state. Next, we consider the question: if a state is difficult to prepare, is the operator reflecting about that state difficult to co
Arkadiusz Wojs, John J. Quinn
Numerical results are presented for the spin excitations of a two-dimensional electron gas confined to a quantum well of width w. Spin waves and charged skyrmion excitations are studied for filling factors nu=1, 3, and 1/3. Phase diagrams for the occurrence of skyrmions of different size as a function of w and the Zeeman energy are calculated. For nu=3, skyr
Maria J. Herrero
We summarize the recent results on the supersymmetric QCD radiative corrections, at the one-loop level, in Higgs and top quark decays, in the context of the Minimal Supersymmetric Standard Model and in the decoupling limit of very heavy SUSY particles. Special attention is devoted to the particular decays $h^0\to b \bar b$, $H^+\to t \bar b$, $H^0\to b \bar
F. Jegerlehner, K. Kolodziej
We accomplish our efforts to obtain predictions for all four-fermion final states of e+ e- annihilation and the corresponding bremsstrahlung reactions which are possible in the framework of the Standard Model. For this purpose we have developed a program EE4FGAMMA. Our predictions are valid for fermions of arbitrary masses and we can obtain results for total
A. Fuzfa, J. M. Gerard, D. Lambert
The Lemaitre and Schwarzschild analytical solutions for a relativistic spherical body of constant density are linked together through the use of the Weyl quadratic invariant. The critical radius for gravitational collapse of an incompressible fluid is shown to vary continuously from 9/8 of the Schwarzschild radius to the Schwarzschild radius itself while the
Arkadiusz Wojs, John J. Quinn
Results are presented of detailed numerical calculations for the spin excitation spectra of a two-dimensional electron gas confined in a quantum well of finite width w, at magnetic fields corresponding to the fractional and integral fillings of the lowest and of excited Landau levels. Spin waves and skyrmions are identified, and their mutual interactions are
- Local versus Nonlocal Order Parameter Field Theories for Quantum Phase Transitionscond-mat.stat-mech
D. Belitz, T. R. Kirkpatrick, Thomas Vojta
General conditions are formulated that allow to determine which quantum phase transitions in itinerant electron systems can be described by a local Landau-Ginzburg-Wilson or LGW theory solely in terms of the order parameter. A crucial question is the degree to which the order parameter fluctuations couple to other soft modes. Three general classes of zero-wa
Xiaotong Song
Contributions to the quark flavor and spin observables from the intrinsic charm in the proton are discussed in the SU(4) quark meson fluctuation model. Our results suggest that the probability of finding the intrinsic charm in the proton is less than 1%. The intrinsic charm helicity is small and negative, $\Delta c \simeq -(0.003\sim 0.015)$. The fraction of
A. V. Lopatin, V. M. Vinokur
We generalize the Beliaev-Popov diagrammatic technique for the problem of interacting dilute Bose gas with weak disorder. Averaging over disorder is implemented by the replica method. Low energy asymptotic form of the Green function confirms that the low energy excitations of the superfluid dirty Boson system are sound waves with velocity renormalized by the
J. Carlson, R. Schiavilla, V. R. Brown, B. F. Gibson
The proton-proton parity-violating longitudinal asymmetry is calculated in the lab-energy range 0--350 MeV, using a number of different, latest-generation strong-interaction potentials--Argonne V18, Bonn-2000, and Nijmegen-I--in combination with a weak-interaction potential consisting of rho- and omega-meson exchanges--the model known as DDH. The complete sc
John Ellis, D. V. Nanopoulos, Keith A. Olive
Working in the context of the CMSSM, we argue that phenomenological constraints now require the universal soft supersymmetry-breaking scalar mass m_0 be non-zero at the input GUT scale. This conclusion is primarily imposed by the LEP lower limit on the Higgs mass and the requirement that the lightest supersymmetric particle not be charged. We find that m_0 >
Alessandro Speranza
The formulation of a model for the evolution of the flow of a solid-liquid mixture (coal-water) in a horizontal pipeline with partial phase separation is the aim of this work. Problems of instabilities due to complex eigenvalues, observed in previous models, seem to be completely solved in the present model, in which we give the genesis of the different term