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cond-mat/9206001
Self Organization and a Dynamical Transition in Traffic Flow Models
A simple model that describes traffic flow in two dimensions is studied. A sharp {\it jamming transition } is found that separates between the low density dynamical phase in which all cars move at maximal speed and the high density jammed phase in which they are all stuck. Self organization effects in both phases are s...
1992-06-02
2009-10-22
[ "cond-mat" ]
Ofer Biham, A. Alan Middleton and Dov Levine
cond-mat/9205016
C_{60} with O defects: Localized states in the gap and oxygen clustering
We propose a Su-Schrieffer-Heeger type electron-phonon model for C_{60} with O defects and solve by the adiabatic approximation. Two new properties are obtained. (1) The dimerization becomes weaker around the oxygen. Two localized states appear deep in the gap. Optical transition between them is allowed. This accords w...
1992-05-28
2007-05-23
[ "cond-mat" ]
Kikuo Harigaya (Fundamental Physics Section, Electrotechnical Laboratory, Japan)
cond-mat/9205014
Lattice distortion and energy level structures in doped C_{60} and C_{70} studied with the extended Su-Schrieffer-Heeger model: Polaron excitations and optical absorption
We extend the Su-Schrieffer-Heeger model of polyacetylene to C_{60} and C_{70} molecules, and solve numerically. The calculations of the undoped systems agree well with the known results. When the system (C_{60} or C_{70}) is doped with one or two electrons (or holes), the additional charges accumulate almost along an ...
1992-05-27
2007-05-23
[ "cond-mat" ]
Kikuo Harigaya (Fundamental Physics Section, Electrotechnical Laboratory, Japan)
cond-mat/9205015
Dynamic scaling and quasi-ordered states in the two dimensional Swift-Hohenberg equation
The process of pattern formation in the two dimensional Swift-Hohenberg equation is examined through numerical and analytic methods. Dynamic scaling relationships are developed for the collective ordering of convective rolls in the limit of infinite aspect ratio. The stationary solutions are shown to be strongly influe...
1992-05-27
2009-10-22
[ "cond-mat" ]
K.R. Elder (1), Jorge Vi\~nals (2) and Martin Grant (1) ((1) Department of Physics, McGill University, Rutherford Building, Montr\'eal, Qu\'ebec, Canada (2) Supercomputer Computations Research Institute, B-186, Florida State University, Tallahassee, Florida)
cond-mat/9205013
Molecular Dynamics Simulation of Compressible Fluid Flow in Two-Dimensional Channels
We study compressible fluid flow in narrow two-dimensional channels using a novel molecular dynamics simulation method. In the simulation area, an upstream source is maintained at constant density and temperature while a downstream reservoir is kept at vacuum. The channel is sufficiently long in the direction of the fl...
1992-05-26
2009-10-22
[ "cond-mat" ]
M. Sun and C. Ebner (Department of Physics, The Ohio State University, Columbus, OH)
cond-mat/9205012
Dispersion of the Third-Order Nonlinear Optical Susceptibility in C_{60} Calculated with a Tight-Binding Model
The frequency dependence of third harmonic generation (THG) in C_{60} is calculated, making use of a tight-binding model for pi-electrons. The magnitudes of the THG, about 10^{-12} esu, near zero frequency, agree with those in experiments for the low-energy region. We can also explain the order of the magnitude, 10^{-1...
1992-05-26
2007-05-23
[ "cond-mat" ]
Kikuo Harigaya and Shuji Abe (Fundamental Physics Section, Electrotechnical Laboratory, Japan)
cond-mat/9205010
Elastic String in a Random Potential
We have studied numerically the dynamics of a directed elastic string in a two-dimensional array of quenched random impurities. The string is driven by a constant transverse force and thermal fluctuations are neglected. There is a transition from pinned to unpinned behavior at a critical value $F_T$ of the driving forc...
1992-05-20
2009-10-22
[ "cond-mat" ]
M. Dong, M.C. Marchetti, A. Alan Middleton, V. Vinokur
cond-mat/9205011
Thermal Rounding of the Charge Density Wave Depinning Transition
The rounding of the charge density wave depinning transition by thermal noise is examined. Hops by localized modes over small barriers trigger ``avalanches'', resulting in a creep velocity much larger than that expected from comparing thermal energies with typical barriers. For a field equal to the $T=0$ depinning fiel...
1992-05-20
2009-10-22
[ "cond-mat" ]
A. Alan Middleton
cond-mat/9205009
Determinant Representation for time and temperature dependent correlation functions in the isotropic XY model in the transverse magnetic field
Astymptotics of temperature correlations is the most dificult problem of stat. mech. Recently it was solved for the impenetrable Bose Gas. The idea is to represent correlation function as $\tau$ function of calssical completely integrable differential equation. Now we start to apply this program to isotropic XY model i...
1992-05-16
2011-06-21
[ "cond-mat" ]
F. Colomo, A. Izergin, V. Korepin, V. Tognetti
cond-mat/9205008
Metals in high magnetic field: a new universality class of Fermi liquids
Parquet equations, describing the competition between superconducting and density-wave instabilities, are solved for a three-dimensional isotropic metal in a high magnetic field when only the lowest Landau level is filled. In the case of a repulsive interaction between electrons, a phase transition to the density-wave ...
1992-05-14
2009-10-22
[ "cond-mat" ]
Victor M. Yakovenko
cond-mat/9205007
Theory of Thermodynamic Magnetic Oscillations in Quasi-One-Dimensional Conductors
The second order correction to free energy due to the interaction between electrons is calculated for a quasi-one-dimensional conductor exposed to a magnetic field perpendicular to the chains. It is found that specific heat, magnetization and torque oscillate when the magnetic field is rotated in the plane perpendicula...
1992-05-14
2009-10-22
[ "cond-mat" ]
Victor M. Yakovenko
cond-mat/9205006
Quaternion Generalization of the Laughlin State and the Three Dimensional Fractional QHE
The 3D state of strongly correlated electrons is proposed, which in the external magnetic field $\vec B$ exhibits the fractional quantum Hall effect, with the zero temperature conductivity tensor $\sigma_{ij} = (e^2/h)(1/m) \sum_k \epsilon_{ijk} B^k/\mid \vec B\mid $. The analog of Landau and Laughlin states in 3D are ...
1992-05-06
2007-05-23
[ "cond-mat" ]
A. V. Balatsky
cond-mat/9205005
Z_N Phases in Hot Gauge Theories
We argue that the \zn phases of hot gauge theories cannot be realized as a real system with an Hermitean density matrix.
1992-05-06
2009-12-30
[ "cond-mat" ]
Wei Chen, Mikhail Dobroliubov, and Gordon Semenoff
cond-mat/9205004
Low Energy Behavior of Quantum Adsorption
We present an exact solution of a 1D model: a particle of incident energy $E$ colliding with a target which is a 1D harmonic ``solid slab'' with $N$ atoms in its ground state; the Hilbert space of the target is restricted to the ($N+1$) states with zero or one phonon present. For the case of a short range interaction, ...
1992-05-05
2007-05-23
[ "cond-mat" ]
D.P. Clougherty and W. Kohn
cond-mat/9205003
Bilinear Quantum Monte Carlo: Expectations and Energy Differences
We propose a bilinear sampling algorithm in Green's function Monte Carlo for expectation values of operators that do not commute with the Hamiltonian and for differences between eigenvalues of different Hamiltonians. The integral representations of the Schroedinger equations are transformed into two equations whose sol...
1992-05-03
2010-01-12
[ "cond-mat" ]
Shiwei Zhang and M.H. Kalos
cond-mat/9205001
Coulomb drag between two-dimensional electron systems
The Coulomb contribution to the temperature-dependent rate of momentum transfer, $1/\tau_D$, between two electron systems in parallel layers is determined by setting up two coupled Boltzmann equations, with the boundary condition that no current flows in the layer where an induced voltage is measured. The effective Cou...
1992-05-01
2009-10-22
[ "cond-mat" ]
Antti-Pekka Jauho and Henrik Smith
cond-mat/9205002
Roughening of Reconstructed Crystal Surfaces and the Hubbard Model
We consider a model of a reconstructed crystal surface, first considered by Villain and Vilfan (Europhys. Lett. 12, p. 523 (1990) and Surf. Sci. 257, p. 368 (1991)) for the gold (110) surface, in which roughening occurs via the formation of anisotropic steps traversing the entire length of the crystal. The model is stu...
1992-05-01
2007-05-23
[ "cond-mat" ]
Leon Balents and Mehran Kardar
cond-mat/9204018
Absence of Dipole Transitions in Vortices of Type II Superconductors
The response of a single vortex to a time dependent field is examined microscopically and an equation of motion for vortex motion at non-zero frequencies is derived. Of interest are frequencies near $\Delta^{2}/E_{F}$, where $\Delta$ is the bulk energy gap and $E_{F}$ is the fermi energy. The low temperature, clean, ex...
1992-04-30
2009-10-22
[ "cond-mat" ]
Theodore C. Hsu (CRTBT-CNRS, Grenoble France)
cond-mat/9204017
On Models with Inverse-Square Exchange
A one-dimensional quantum N-body system of either fermions or bosons with $SU(n)$ colors interacting via inverse-square exchange is presented in this article. A class of eigenstates of both the continuum and lattice version of the model Hamiltonians is constructed in terms of the Jastrow-product type wave function. The...
1992-04-29
2009-10-22
[ "cond-mat" ]
Z.N.C. Ha and F.D.M. Haldane
cond-mat/9204014
Blockspin Cluster Algorithms for Quantum Spin Systems
Cluster algorithms are developed for simulating quantum spin systems like the one- and two-dimensional Heisenberg ferro- and anti-ferromagnets. The corresponding two- and three-dimensional classical spin models with four-spin couplings are maped to blockspin models with two-blockspin interactions. Clusters of blockspin...
1992-04-28
2009-10-22
[ "cond-mat" ]
U.-J. Wiese and H.-P. Ying
cond-mat/9204015
Logarithmically slow domain growth in nonrandomly frustrated systems: Ising models with competing interactions
It is known that in systems which contain randomness explicitly in their Hamiltonians (e.g., due to impurities), the characteristic size L of the ordered domains can grow only logarithmically with time t following a quench below the transition temperature. However, in systems without such imposed randomness, much faste...
1992-04-28
2009-10-22
[ "cond-mat" ]
Joel D. Shore, Mark Holzer, and James P. Sethna
cond-mat/9204016
Logarithmically slow domain growth in nonrandomly frustrated systems--- A summary of the major results
Here, we summarize the most important results of our study of logarithmically slow growth of domains following a quench in two models without randomness in their Hamiltonians. This is a slightly updated version of a paper to appear in the Proceedings of the 1st Annual Tohwa University International Symposium, Fukuoka...
1992-04-28
2016-08-31
[ "cond-mat" ]
Joel D. Shore, James P. Sethna, Mark Holzer, and Veit Elser
cond-mat/9204013
Beyond the ``principle of local symmetry'': derivation of a general crack propagation law
We derive a general crack propagation law for slow brittle cracking, in two and three dimensions, using symmetry, gauge invariance, and gradient expansions. Our derivation provides explicit justification for the ``principle of local symmetry,'' which has been used extensively to describe two dimensional crack growth, b...
1992-04-24
2009-10-22
[ "cond-mat" ]
Jennifer Hodgdon and James P. Sethna
cond-mat/9204012
Tweed in Martensites: A Potential New Spin Glass
We've been studying the ``tweed'' precursors above the martensitic transition in shape--memory alloys. These characteristic cross--hatched modulations occur for hundreds of degrees above the first--order shape--changing transition. Our two--dimensional model for this transition, in the limit of infinite elastic anisotr...
1992-04-23
2015-06-25
[ "cond-mat" ]
James P. Sethna, Sivan Kartha, Teresa Cast'an, and James A. Krumhansl
cond-mat/9204011
Fredholm Determinant Representation for Correlation Functions in XXO Heisenberg Chain
Space and time dependent temepreture correlation fucntions in the Hiesenberg XXO chain are evaluated in the magnetic field. The other name of the model is isotropic xy model in the transverse magnetic field. In the thermodynamic limit correlations in the model are represented as Fredhom determinanat. We expect this to ...
1992-04-22
2008-02-03
[ "cond-mat" ]
F.Colomo, A.G. Izergin, V. Korepin
cond-mat/9204010
Meissner Effect and Constraints
We notice some beautiful geometrical defects found in liquid crystals, and explain them by imposing a constraint. We study the way constraints can occur, and introduce the concept of massive fields. We develop the theory of magnetic field expulsion in superconductors as an example. We notice strong analogies with the f...
1992-04-22
2008-02-03
[ "cond-mat" ]
James P. Sethna, Ming Huang
cond-mat/9204009
Order Parameters, Broken Symmetry, and Topology
We introduce the theoretical framework we use to study the bewildering variety of phases in condensed--matter physics. We emphasize the importance of the breaking of symmetries, and develop the idea of an order parameter through several examples. We discuss elementary excitations and the topological theory of defects.
1992-04-22
2009-09-25
[ "cond-mat" ]
James P. Sethna
cond-mat/9204008
Image of the Energy Gap Anisotropy in the Vibrational Spectum of a High Temperature Superconductor
We present a new method of determining the anisotropy of the gap function in layered high-Tc superconductors. Careful inelastic neutron scattering measurements at low temperature of the phonon dispersion curves in the (100) direction in La_(1.85)Sr_(.15)CuO_4 would determine whether the gap is predominately s-wave or d...
1992-04-21
2009-10-22
[ "cond-mat" ]
Michael E. Flatte
cond-mat/9204007
Theory of Directed Polymers
We develop a theory of polymers in a nematic solvent by exploiting an analogy with two-dimensional quantum bosons at zero temperature. We argue that the theory should also describe polymers in an {\sl isotropic} solvent. The dense phase is analyzed in a Bogoliubov-like approximation, which assumes a broken symmetry in ...
1992-04-14
2009-10-22
[ "cond-mat" ]
R.D. Kamien, P. Le Doussal, and D.R. Nelson
cond-mat/9204006
Chirality Ordering of Chiral Spin Liquids
We study the effect of introducing a weak antiferromagnetic interplanar exchange coupling in the two dimensional frustrated Heisenberg model. We show that a ferromagnetic(FM) ordering of chirality - {\it i.e.}, same chirality on adjacent planes - is energetically favoured, thus leading to bulk violation of the discrete...
1992-04-14
2009-10-22
[ "cond-mat" ]
D. M. Gaitonde, Dileep P. Jatkar and Sumathi Rao
cond-mat/9204005
Investigations of Pairing in Anyon Systems
We investigate pairing instabilities in the Fermi-liquid-like state of a single species of anyons. We describe the anyons as Fermions interacting with a Chern-Simons gauge field and consider the weak coupling limit where their statistics approaches that of Fermions. We show that, within the conventional BCS approach, d...
1992-04-13
2009-10-22
[ "cond-mat" ]
M.I.Dobroliubov, I.I.Kogan, and G.W.Semenoff
cond-mat/9204004
Physics beyond quasi-particles: Spectrum and completeness of the 3 state superintegrable chiral Potts model
We find the rules which count the energy levels of the 3 state superintegrable chiral Potts model and demonstrate that these rules are complete. We then derive the complete spectrum of excitations in the thermodynamic limit in the massive phase and demonstrate the existence of excitations which do not have a quasi-part...
1992-04-13
2007-05-23
[ "cond-mat" ]
Srinandan Dasmahapatra, Rinat Kedem and Barry M. McCoy
cond-mat/9204003
A novel class of singlet superconductors
A new class of singlet superconductors with a gap function $\Delta(\bk, \omega_n)$ which is {\it odd} in both momentum and Matsubara frequency is considered. Some of the physical properties of this superconductivity are discussed and it is argued that: i) the electron-phonon interaction can produce this kind of pairing...
1992-04-10
2007-05-23
[ "cond-mat" ]
Alexander Balatsky and Elihu Abrahams
cond-mat/9204002
Spin Singlet Quantum Hall Effect and Nonabelian Landau-Ginzburg Theory
We show that the Halperin-Haldane SQHE wave function can be written in the form of a product of a wave function for charged semions in a magnetic field and a wave function for the Chiral Spin Liquid of neutral spin-$\12$ semions. We introduce field-theoretic model in which the electron operators are factorized in terms...
1992-04-10
2015-06-25
[ "cond-mat" ]
Alexander Balatsky (Los Alamos National Laboratory)
cond-mat/9204001
Universal quantum critical dynamics of two-dimensional antiferromagnets
The universal dynamic and static properties of two dimensional antiferromagnets in the vicinity of a zero-temperature phase transition from long-range magnetic order to a quantum disordered phase are studied. Random antiferromagnets with both N\'{e}el and spin-glass long-range magnetic order are considered. Explicit qu...
1992-04-10
2009-10-22
[ "cond-mat" ]
Subir Sachdev and Jinwu Ye
cond-mat/9603180
Lack of Self-affinity and Anomalous Roughening in Growth Processes
We contrast analytical results of a variety of growth models involving subdiffusion, thermal noise and quenched disorder with simulations of these models, concluding that the assumed self-affinity property is more an exception than a rule. In our two dimensional models, self-affine surfaces may only appear when the rou...
1992-03-28
2016-08-15
[ "cond-mat" ]
Juan M. L\'opez and Miguel A. Rodr\'iguez (Instituto de Fisica de Cantabria CSIC-UC, Spain)
cs/9301116
The problem of compatible representatives
The purpose of this note is to attach a name to a natural class of combinatorial problems and to point out that this class includes many important special cases. We also show that a simple problem of placing nonoverlapping labels on a rectangular map is NP-complete.
1992-07-01
2008-02-03
[ "cs.DS", "math.CO" ]
Donald E. Knuth, Arvind Raghunathan
funct-an/9212005
A Fredholm Operator Approach To Morita Equivalence
Given C*-algebras A and B and an imprimitivity A-B-bimodule X, we construct an explicit isomorphism X_* : K_i(A) --> K_i(B) where K_i denote the complex K-theory functors for i=0, 1. Our techniques do not require separability nor existence of countable approximate identities. We thus extend, to general C*-algebras, the...
1992-12-31
2008-02-03
[ "funct-an", "math.OA" ]
Ruy Exel
funct-an/9212004
The Soft Torus II: A Variational Analysis of Commutator Norms
The field of C*-algebras over the interval [0,2] for which the fibers are the Soft Tori is shown to be continuous. This result is applied to show that any pair of non-commuting unitary operators can be perturbed (in a weak sense) in such a way to decrease the commutator norm. Perturbations in norm are also considered a...
1992-12-19
2008-02-03
[ "funct-an", "math.OA" ]
Ruy Exel
funct-an/9212003
Compression Limit Algebras
This paper studies direct limits of full upper triangular matrix algebras with embeddings which are not *-extendible. A representation of the limit algebra is found so that the generated C*-algebra is the C*-envelope. Some examples are described.
1992-12-18
2008-02-03
[ "funct-an", "math.OA" ]
Alan Hopenwasser, Cecelia Laurie
funct-an/9212002
On von Neumann algebras which are complemented subspaces of B(H)
If there exists a completely bounded projection of B(H) onto a von Neumann algebra M on H, then M is injective. If there exists a bounded projection and M is properly infinite, the same conclusion holds.
1992-12-14
2008-02-03
[ "funct-an", "math.OA" ]
Erik Christensen and Allan M. Sinclair
funct-an/9212001
The free abelian topological group and the free locally convex space on the unit interval
We give a complete description of the topological spaces $X$ such that the free abelian topological group $A(X)$ embeds into the free abelian topological group $A(I)$ of the closed unit interval. In particular, the free abelian topological group $A(X)$ of any finite-dimensional compact metrizable space $X$ embeds into ...
1992-12-11
2008-02-03
[ "funct-an", "math.OA" ]
A.G. Leiderman, S.A. Morris and V.G. Pestov
funct-an/9211014
Non-commutative spheres and numerical quantum mechanics
We discuss some basic issues that arise when one attempts to model quantum mechanical systems on a computer, and we describe the mathematical structure of the resulting discretized cannonical commutation relations.
1992-11-30
2008-02-03
[ "funct-an", "math.OA" ]
William Arveson
funct-an/9211015
Discretized CCR algebras
We discuss how the canonical commutation relations must be modified in order to make appropriate numerical models of quantum systems. The C*-algebras associated with the discretized CCRs are the non-commutative spheres of Bratteli, Elliott, Evans and Kishimoto.
1992-11-30
2008-02-03
[ "funct-an", "math.OA" ]
William Arveson
funct-an/9211012
Interpolated free group factors
The interpolated free group factors L(F_r), 1 < r <= \infty, are defined and proofs of their properties with respect to compression by projections and taking free products are proved. Hence it follows that all the free group factor are isomorphic to each other or none of them are. These factors were defined and these p...
1992-11-28
2008-02-03
[ "funct-an", "math.OA" ]
Ken Dykema
funct-an/9211013
Free products of hyperfinite von Neumann algebras and free dimension
The free product of an arbitrary pair of finite hyperfinite von Neumann algebras is examined, and the result is determined to be the direct sum of a finite dimensional algebra and an interpolated free group factor $L(\freeF_r)$. The finite dimensional part depends on the minimal projections of the original algebras and...
1992-11-28
2008-02-03
[ "funct-an", "math.OA" ]
Ken Dykema
funct-an/9211011
On certain free product factors via an extended matrix model
Voiculescu's random matrix model for freeness is extended to the non-Gaussian case and also the case of constant block diagonal matrices. Thus we are able to investigate free products of free group factors with matrix algebras and with the hyperfinite II$_1$ factor, showing that $$ L(F_n) * R = L(F_(n+1)) $$ for $n \ge...
1992-11-28
2016-08-31
[ "funct-an", "math.OA" ]
Ken Dykema
funct-an/9211009
Spectral Invariance of Dense Subalgebras of Operator Algebras
We define the notion of strong spectral invariance for a dense Frechet subalgebra A of a Banach algebra B. We show that if A is strongly spectral invariant in a C*-algebra B, and G is a compactly generated polynomial growth Type R Lie group, not necessarily connected, then the smooth crossed product G\rtimes A is spect...
1992-11-27
2016-02-15
[ "funct-an", "math.OA" ]
Larry B. Schweitzer
funct-an/9211010
Dense m-convex Frechet Subalgebras of Operator Algebra Crossed Products by Lie Groups
Let A be a dense Frechet *-subalgebra of a C*-algebra B. (We do not require Frechet algebras to be m-convex.) Let G be a Lie group, not necessarily con- nected, which acts on both $A$ and B by *-automorphisms, and let \s be a sub- multiplicative function from G to the nonnegative real numbers. If \s and the action of G...
1992-11-27
2016-02-15
[ "funct-an", "math.OA" ]
Larry B. Schweitzer
funct-an/9211008
An analytic structure emerging in presence of infinitely many odd coordinates
This is a contribution to the program of featuring even geometry as a ``collective effect in infinite-dimensional odd geometry,'' as suggested by Manin. We show that the (Gel'fand) spectrum of the locally convex nonstandard hull (in the sense of Luxemburg) of a grassmannian algebra with infinitely many odd generators c...
1992-11-27
2008-02-03
[ "funct-an", "math.OA" ]
Vladimir G. Pestov
funct-an/9211007
Representable K-theory of Smooth Crossed Products by R and Z
We show that the Thom isomorphism and the Pimsner-Voiculescu exact sequence both hold for smooth crossed products of Frechet algebras by R and Z respectively. We also obtain the same results for L^{1}-crossed products of Banach algebras by R and Z.
1992-11-25
2016-02-15
[ "funct-an", "math.OA" ]
N. Christopher Phillips and Larry B. Schweitzer
funct-an/9211005
A Short Proof that $M_{n}(A)$ is local if $A$ is local and Fr\'echet
We give a short and very general proof of the fact that the property of a dense Fr\'echet subalgebra of a Banach algebra being local, or closed under the holomorphic functional calculus in the Banach algebra, is preserved by tensoring with the $n\times n$ matrix algebra of the complex numbers.
1992-11-25
2016-02-12
[ "funct-an", "math.OA" ]
Larry B. Schweitzer
funct-an/9211006
A Non-Spectral Dense Banach Subalgebra of the Irrational Rotation Algebra
We give an example of a dense, simple, unital Banach subalgebra $A$ of the irrational rotation C*-algebra $B$, such that $A$ is not a spectral subalgebra of $B$. This answers a question posed in T.W. Palmer's paper [1].
1992-11-25
2016-02-15
[ "funct-an", "math.OA" ]
Larry B. Schweitzer
funct-an/9211004
Approximately Finite C*-Algebras and Partial Automorphisms
We prove that every AF-algebra is isomorphic to a crossed product of a commutative AF-algebra by a partial automorphism. The case of UHF-algebras is treated in detail.
1992-11-24
2008-02-03
[ "funct-an", "math.OA" ]
Ruy Exel
funct-an/9211003
Improper filtrations for C*-algebras: spectra of unilateral tridiagonal operators
We extend the results of our previous paper "C*-algebras and numerical linear algebra" to cover the case of "unilateral" sections. This situation bears a close resemblance to the case of Toeplitz operators on Hardy spaces, in spite of the fact that the operators here are far from Toeplitz operators. In particular, ther...
1992-11-23
2008-02-03
[ "funct-an", "math.OA" ]
William Arveson
funct-an/9211002
C*-algebras and numerical linear algebra
We consider problems associated with the computation of spectra of self-adjoint operators in terms of the eigenvalue distributions of their n x n sections. Under rather general circumstances, we show how these eigenvalues accumulate near points of the essential spectrum of the given operator, and we prove that their av...
1992-11-22
2008-02-03
[ "funct-an", "math.OA" ]
William Arveson
funct-an/9211001
Circle Actions on C*-Algebras, Partial Automorphisms and a Generalized Pimsner-Voiculescu Exact Sequence
We introduce a method to study C*-algebras possessing an action of the circle group, from the point of view of its internal structure and its K-theory. Under relatively mild conditions our structure Theorem shows that any C*-algebra, where an action of the circle is given, arises as the result of a construction that ge...
1992-11-22
2016-08-31
[ "funct-an", "math.OA" ]
Ruy Exel
funct-an/9209001
Extremal Selections of Multifunctions Generating a Continuous Flow
Let $F:[0,T]\times\R^n\mapsto 2^{\R^n}$ be a continuous multifunction with compact, not necessarily convex values. In this paper, we prove that, if $F$ satisfies the following Lipschitz Selection Property: \begin{itemize} \item[{(LSP)}] {\sl For every $t,x$, every $y\in \overline{co} F(t,x)$ and $\varepsilon>0$, there ...
1992-09-09
2016-08-31
[ "funct-an", "math.FA" ]
Alberto Bressan and Graziano Crasta
funct-an/9208001
Universal arrows to forgetful functors from categories of topological algebra
We survey the present trends in theory of universal arrows to forgetful functors from various categories of topological algebra and functional analysis to categories of topology and topological algebra. Among them are free topological groups, free locally convex spaces, free Banach-Lie algebras, and much more. An accen...
1992-08-20
2008-02-03
[ "funct-an", "math.OA" ]
Vladimir G. Pestov
funct-an/9205003
Nonstandard hulls of Banach-Lie groups and algebras
We propose a new construction of Banach-Lie groups and algebras relying on nonstandard analysis. A major standard application is the Local Theorem which to certain extent reduces the problem of associating a Lie group to a given banach-Lie algebra to a similar problem for finitely generated Lie subalgebras. We discuss ...
1992-05-19
2008-02-03
[ "funct-an", "math.OA" ]
Vladimir G. Pestov
funct-an/9205002
Integral representation for a class of $C^1$-convex functionals
In view of the applications to the asymptotic analysis of a family of obstacle problems, we consider a class of convex local functionals $F(u,A)$, defined for all functions $u$ in a suitable vector valued Sobolev space and for all open sets $A$ in ${\bf R}^n$. Sufficient conditions are given in order to obtain an integ...
1992-05-11
2008-02-03
[ "funct-an", "math.FA" ]
Gianni Dal Maso, Anneliese Defranceschi, Enrico Vitali
funct-an/9205001
A Baire Category Approach to the Bang-Bang Property
Aim of this paper is to develop a new technique, based on the Baire category theorem, in order to establish the closure of reachable sets and the existence of optimal trajectories for control systems, without the usual convexity assumptions. The bang-bang property is proved for a new class of ``concave" multifunctions,...
1992-05-06
2008-02-03
[ "funct-an", "math.FA" ]
Alberto Bressan and Benedetto Piccoli
gr-qc/9212016
String Instabilities in Black Hole Spacetimes
We study the emergence of string instabilities in $D$ - dimensional black hole spacetimes (Schwarzschild and Reissner - Nordstr\o m), and De Sitter space (in static coordinates to allow a better comparison with the black hole case). We solve the first order string fluctuations around the center of mass motion at spatia...
1992-12-30
2009-10-22
[ "gr-qc", "hep-th" ]
C.O.Lousto and N. S\'anchez
gr-qc/9212015
(1+1)-Dimensional Methods for General Relativity
This is an article contributed to the Brill Festschrift, in honor of the 60th birthday of Prof. D.R. Brill, which will appear in the Vol.2 of the Proceedings of the International Symposia on Directions in General Relativity. In this article we present the (1+1)-dimensional method for studying general relativity of 4-di...
1992-12-29
2007-05-23
[ "gr-qc" ]
J.H. Yoon
gr-qc/9212014
Anisotropic and inhomogeneous cosmologies
This review was given at the 65th birthday meeting of D.W. Sciama, The Renaissance of General Relativity and Cosmology, to be published by Cambridge University Press. It presents progress in the understanding of non-standard relativistic cosmologies during Sciama's career, organized by the areas of application rather t...
1992-12-21
2008-02-12
[ "gr-qc" ]
M.A.H. MacCallum
gr-qc/9212013
Inhomogeneous and anisotropic cosmologies
This is a review of cosmological models prepared for the Pont d'Oye workshop on the origin of structure in the universe. The classes of models are discussed in turn, and then some of their uses are considered.
1992-12-21
2011-03-28
[ "gr-qc" ]
M.A.H. MacCallum
gr-qc/9212012
Collisions of Einstein-Conformal Scalar Waves
A large class of solutions of the Einstein-conformal scalar equations in D=2+1 and D=3+1 is identified. They describe the collisions of asymptotic conformal scalar waves and are generated from Einstein-minimally coupled scalar spacetimes via a (generalized) Bekenstein transformation. Particular emphasis is given to the...
1992-12-18
2016-08-17
[ "gr-qc" ]
C. Klim\v{c}\'ik and P. Koln\'ik
gr-qc/9212011
A Nonlinear Model of a Quantum Minisuperspace System with Back Reaction
We consider the quantum evolution of the space-independent mode of a $\lambda {\phi}^4$ theory as a minisuperspace in the space of all $\phi$. The motion of the wave packet in the minisuperspace is then compared to the motion of a wave packet in a larger minisuperspace consisting of the original minisuperspace plus one...
1992-12-16
2011-07-19
[ "gr-qc" ]
Marcos Rosenbaum, Michael P. Ryan and Sukanya Sinha
gr-qc/9212010
Black Hole Tunneling Entropy and the Spectrum of Gravity
The tunneling approach for entropy generation in quantum gravity is applied to black holes. The area entropy is recovered and shown to count only a tiny fraction of the black hole degeneracy. The latter stems from the extension of the wave function outside the barrier. In fact the semi-classical analysis leads to infin...
1992-12-15
2010-04-06
[ "gr-qc", "hep-th" ]
A. Casher and F. Englert
gr-qc/9212009
Magnetically Charged Black Holes and their Stability
We study magnetically charged black holes in the Einstein-Yang-Mills-Higgs theory in the limit of infinitely strong coupling of the Higgs field. Using mixed analytical and numerical methods we give a complete description of static spherically symmetric black hole solutions, both abelian and nonabelian. In particular, w...
1992-12-14
2010-11-01
[ "gr-qc", "hep-th" ]
Peter C. Aichelburg and Piotr Bizon
gr-qc/9212007
Weak-Field Gravity of Revolving Circular Cosmic Strings
A weak-field solution of Einstein's equations is constructed. It is generated by a circular cosmic string revolving in its plane about the centre of the circle. (The revolution is introduced to prevent the string from collapsing.) This solution exhibits a conical singularity, and the corresponding deficit angle is the ...
1992-12-10
2009-10-22
[ "gr-qc" ]
Des J. Mc Manus and Michel A. Vandyck
gr-qc/9212006
On Cosmological Isotropy, Quantum Cosmology and the Weyl Curvature Hypothesis
The increasing entropy, large-scale isotropy and approximate flatness of the universe are considered in the context of signature change, which is a classical model of quantum tunnelling in quantum cosmology. The signature change hypothesis implies an initial inflationary epoch, the magnetic half of the Weyl curvature h...
1992-12-10
2010-04-06
[ "gr-qc" ]
Sean A. Hayward
gr-qc/9212008
The Coherent State Representation of Quantum Fluctuations in the Early Universe
Using the squeezed state formalism the coherent state representation of quantum fluctuations in an expanding universe is derived. It is shown that this provides a useful alternative to the Wigner function as a phase space representation of quantum fluctuations. The quantum to classical transition of fluctuations is nat...
1992-12-10
2009-10-22
[ "gr-qc", "astro-ph" ]
A.L. Matacz
gr-qc/9212005
Dark Matter and Non-Newtonian Gravity From General Relativity on a Stringy Background
An exact solution of Einstein's field equations for a static spherically symmetric medium with a radially boost invariant energy-momentum tensor is presented. In the limit of an equation of state corresponding to a distribution of radially directed strings there is a $1/r$ correction to Newton's force law. At large dis...
1992-12-09
2007-05-23
[ "gr-qc" ]
Harald H. Soleng
gr-qc/9212002
Galilean Theories of Gravitation
A generalization of Newtonian gravitation theory is obtained by a suitable limiting procedure from the ADM action of general relativity coupled to a mass-point. Three particular theories are discussed and it is found that two of them are invariant under an extended Galilei gauge group.
1992-12-03
2008-02-03
[ "gr-qc" ]
R. De Pietri, L. Lusanna, M. Pauri
gr-qc/9212003
Exotic Differentiable Structures and General Relativity
We review recent developments in differential topology with special concern for their possible significance to physical theories, especially general relativity. In particular we are concerned here with the discovery of the existence of non-standard (``fake'' or ``exotic'') differentiable structures on topologically sim...
1992-12-03
2009-10-22
[ "gr-qc" ]
Carl H. Brans and Duane Randall
gr-qc/9212004
Quantum Vacuum Instability Near Rotating Stars
We discuss the Starobinskii-Unruh process for the Kerr black hole. We show how this effect is related to the theory of squeezed states. We then consider a simple model for a highly relativistic rotating star and show that the Starobinskii-Unruh effect is absent.
1992-12-03
2009-10-22
[ "gr-qc" ]
A L Matacz, A C Ottewill and P C W Davies
gr-qc/9212001
Cosmic Censorship in 2-Dimensional Dilaton Gravity
The global structure of 2-dimensional dilaton gravity is studied, attending in particular to black holes and singularities. A gravitational energy is defined and shown to be positive at spatial singularities and negative at temporal singularities. Trapped points are defined, and it is shown that spatial singularities a...
1992-12-02
2010-04-06
[ "gr-qc" ]
Sean A. Hayward
gr-qc/9211028
Thawing the Frozen Formalism: The Difference Between Observables and What We Observe
In a parametrized and constrained Hamiltonian system, an observable is an operator which commutes with all (first-class) constraints, including the super-Hamiltonian. The problem of the frozen formalism is to explain how dynamics is possible when all observables are constants of the motion. An explicit model of a measu...
1992-11-25
2007-05-23
[ "gr-qc", "hep-th" ]
Arlen Anderson
gr-qc/9211027
Chaotic Friedmann-Robertson-Walker Cosmology
We show that the dynamics of a spatially closed Friedmann - Robertson - Walker Universe conformally coupled to a real, free, massive scalar field, is chaotic, for large enough field amplitudes. We do so by proving that this system is integrable under the adiabatic approximation, but that the corresponding KAM tori brea...
1992-11-23
2010-04-06
[ "gr-qc" ]
E. Calzetta and C. El Hasi
gr-qc/9211026
Cauchy horizon singularity without mass inflation
A perturbed Reissner-Nordstr\"om-de Sitter solution is used to emphasize the nature of the singularity along the Cauchy horizon of a charged spherically symmetric black hole. For these solutions, conditions may prevail under which the mass function is bounded and yet the curvature scalar $R_{\alpha\beta\gamma\delta} R^...
1992-11-20
2009-10-22
[ "gr-qc", "astro-ph" ]
P.R. Brady, D. Nunez and S. Sinha
gr-qc/9211023
Gravitational Waves in the Nonsymmetric Gravitational Theory
We prove that the flux of gravitational radiation from an isolated source in the Nonsymmetric Gravitational Theory is identical to that found in Einstein's General Theory of Relativity.
1992-11-19
2010-11-01
[ "gr-qc" ]
N. J. Cornish, J. W. Moffat and D. C. Tatarski
gr-qc/9211025
Spin effects in the inspiral of coalescing compact binaries
We derive the contributions of spin-orbit and spin-spin coupling to the gravitational radiation from coalescing binary systems of spinning compact objects. We calculate spin effects in the symmetric, trace-free radiative multipoles that determine the gravitational waveform, and the rate of energy loss. Assuming a balan...
1992-11-19
2010-01-06
[ "gr-qc" ]
Lawrence E. Kidder and Clifford M. Will (Washington University, St. Louis) and Alan G. Wiseman (Northwestern University, Evanston)
gr-qc/9211024
Tunneling in Anisotropic Cosmological Models
Tunneling rate is investigated in homogenous and anisotropic cosmologies. The calculations is done by two methods: Euclidean and Hamiltonian approaches. It is found that the probability decreases exponentialy as anisotropy is increased.
1992-11-19
2010-04-06
[ "gr-qc" ]
R. Mansouri and M.Mohazzab (BROWN)
gr-qc/9211022
Quantum Gravity by the Complex Canonical Formulation
The basic features of the complex canonical formulation of general relativity and the recent developments in the quantum gravity program based on it are reviewed. The exposition is intended to be complementary to the review articles available already and some original arguments are included. In particular the conventio...
1992-11-18
2010-11-01
[ "gr-qc" ]
Hideo Kodama
gr-qc/9211021
Dilaton Contributions to the Cosmic Gravitational Wave Background
We consider the cosmological amplification of a metric perturbation propagating in a higher-dimensional Brans-Dicke background, including a non trivial dilaton evolution. We discuss the properties of the spectral energy density of the produced gravitons (as well as of the associated squeezing parameter), and we show th...
1992-11-17
2009-10-22
[ "gr-qc", "hep-th" ]
M.Gasperini and M.Giovannini
gr-qc/9211020
Superluminary Universe: A Possible Solution to the Initial Value Problem in Cosmology
The spontaneous breaking of local Lorentz invariance in the early Universe, associated with a first order phase transition at a critical time $t_c$, generates a large increase in the speed of light and a superluminary communication of information occurs, allowing all regions in the Universe to be causally connected. Th...
1992-11-16
2008-11-26
[ "gr-qc", "astro-ph", "hep-th" ]
J. W. Moffat
gr-qc/9211019
What can we learn from the study of non-perturbative quantum general relativity?
I attempt to answer the question of the title by giving an annotated list of the major results achieved, over the last six years, in the program to construct quantum general relativity using the Ashtekar variables and the loop representation. A summary of the key open problems is also included. Also included are exposi...
1992-11-15
2007-05-23
[ "gr-qc" ]
Lee Smolin
gr-qc/9211018
Generalized Fierz Identities and the Superselection Rule for Geometric Multispinors
The inverse problem, to reconstruct the general multivector wave function from the observable quadratic densities, is solved for 3D geometric algebra. It is found that operators which are applied to the right side of the wave function must be considered, and the standard Fierz identities do not necessarily hold except ...
1992-11-14
2009-09-25
[ "gr-qc", "hep-th" ]
William M. Pezzaglia Jr. (Physics, Santa Clara University)
gr-qc/9211016
Vacuum Polarisation and the Black Hole Singularity
In order to investigate the effects of vacuum polarisation on mass inflation singularities, we study a simple toy model of a charged black hole with cross flowing radial null dust which is homogeneous in the black hole interior. In the region $r^2 \ll e^2$ we find an approximate analytic solution to the classical field...
1992-11-13
2010-04-06
[ "gr-qc" ]
W. G. Anderson, P. R. Brady, and R. Camporesi
gr-qc/9211017
The Relation between Physical and Gravitational Geometry
The appearance of two geometries in one and the same gravitational theory is familiar. Usually, as in the Brans-Dicke theory or in string theory, these are conformally related Riemannian geometries. Is this the most general relation between the two geometries allowed by physics ? We study this question by supposing tha...
1992-11-13
2011-07-18
[ "gr-qc", "astro-ph", "hep-th" ]
Jacob D. Bekenstein (University of California at Santa Barbara and Hebrew University of Jerusalem)
gr-qc/9211015
Discrete Symmetry, Non-Commutative Geometry and Gravity
We describe the geomety of a set of scalar fields coupled to gravity. We consider the formalism of a differential Z_2-graded algebra of $2\times 2$ matrices whose elements are differential forms on space-time. The connection and the vierbeins are extended to incorporate additional scalar and vector fields. The resultin...
1992-11-10
2007-05-23
[ "gr-qc", "hep-th" ]
N. Mohammedi
gr-qc/9211014
Unification of Gravity and Yang-Mills Theory in (2+1)-Dimensions
A gauge and diffeomorphism invariant theory in (2+1)-dimensions is presented in both first and second order Lagrangian form as well as in a Hamiltonian form. For gauge group $SO(1,2)$, the theory is shown to describe ordinary Einstein gravity with a cosmological constant. With gauge group $G^{tot}=SO(1,2)\otimes G^{YM}...
1992-11-10
2009-10-22
[ "gr-qc", "hep-th" ]
Peter Peldan
gr-qc/9211012
Inflating Lorentzian Wormholes
It has been speculated that Lorentzian wormholes of the Morris- Thorne type might be allowed by the laws of physics at submicroscopic, e.g. Planck, scales and that a sufficiently advanced civilization might be able to enlarge them to classical size. The purpose of this paper is to explore the possibility that inflation...
1992-11-09
2009-10-22
[ "gr-qc" ]
Thomas A. Roman
gr-qc/9211013
Gauge Formulation of the Spinning Black Hole in (2+1)-Dimensional Anti-de Sitter Space
We compute the group element of SO(2,2) associated with the spinning black hole found by Ba\~nados, Teitelboim and Zanelli in (2+1)-dimensional anti-de Sitter space-time. We show that their metric is built with SO(2,2) gauge invariant quantities and satisfies Einstein's equations with negative cosmological constant eve...
1992-11-09
2009-10-22
[ "gr-qc", "hep-th" ]
Daniel Cangemi, Martin Leblanc and Robert B. Mann
gr-qc/9211011
Weak-Field Gravity of Circular Cosmic Strings
A weak-field solution of Einstein's equations is constructed. It is generated by a circular cosmic string externally supported against collapse. The solution exhibits a conical singularity, and the corresponding deficit angle is the same as for a straight string of the same linear energy density. This confirms the defi...
1992-11-09
2009-10-22
[ "gr-qc" ]
Shane J. Hughes, Des J. Mc Manus, and Michel A. Vandyck
gr-qc/9211010
Gauge (In)variance, Mass and Parity in D=3 Revisited
We analyze the degree of equivalence between abelian topologically massive, gauge-invariant, vector or tensor parity doublets and their explicitly massive, non-gauge, counterparts. We establish equivalence of field equations by exploiting a generalized Stueckelberg invariance of the gauge systems. Although the respecti...
1992-11-06
2009-11-19
[ "gr-qc" ]
S. Deser
gr-qc/9211008
Gauge Field Back-reaction on a Black Hole
The order $\hbar$ fluctuations of gauge fields in the vicinity of a blackhole can create a repulsive antigravity region extending out beyond the renormalized Schwarzschild horizon. If the strength of this repulsive force increases as higher orders in the back-reaction are included, the formation of a wormhole-like obje...
1992-11-05
2009-10-22
[ "gr-qc", "astro-ph" ]
David Hochberg and Thomas W. Kephart
gr-qc/9211009
Positivity of Entropy in the Semi-Classical Theory of Black Holes and Radiation
Quantum stress-energy tensors of fields renormalized on a Schwarzschild background violate the classical energy conditions near the black hole. Nevertheless, the associated equilibrium thermodynamical entropy $\Delta S$ by which such fields augment the usual black hole entropy is found to be positive. More precisely, t...
1992-11-05
2009-12-30
[ "gr-qc" ]
David Hochberg, Thomas Kephart and James W. York
gr-qc/9211006
Wormhole Cosmology and the Horizon Problem
We construct an explicit class of dynamic lorentzian wormholes connecting Friedmann-Robertson-Walker (FRW) spacetimes. These wormholes can allow two-way transmission of signals between spatially separated regions of spacetime and could permit such regions to come into thermal contact. The cosmology of a network of earl...
1992-11-04
2009-10-22
[ "gr-qc", "hep-th" ]
David Hochberg and Thomas W. Kephart