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gr-qc/9303034
Junction Conditions for Signature Change
The change of signature of a metric is explained using simple examples and methods. The Klein-Gordon field on a signature-changing background is discussed, and it is shown how the approach of Dray et al.\ can be corrected to ensure that the Klein-Gordon equation holds. Isotropic cosmologies are discussed, and it is sho...
1993-03-29
2008-02-03
[ "gr-qc" ]
Sean A. Hayward
gr-qc/9303029
Critical Phenomena for Riemannian Manifolds: Simple Homotopy and Simplicial Quantum Gravity
We show how Gromov's spaces of bounded geometries provide a general mathematical framework for addressing and solving many of the issues of $3D$-simplicial quantum gravity. In particular, we establish entropy estimates characterizing the asymptotic distribution of combinatorially inequivalent triangulated $3$-manifolds...
1993-03-26
2007-08-09
[ "gr-qc" ]
M. Carfora, A. Marzuoli
gr-qc/9303031
Uncertainty Relation at Finite Temperature
We use the quantum Brownian model to derive the uncertainty relation for a quantum open system. We examine how the fluctuations of a quantum system evolve after it is brought in contact with a heat bath at finite temperature. We study the decoherence and relaxation processes and use this example to examine 1) the relat...
1993-03-26
2015-06-25
[ "gr-qc" ]
B. L. Hu and Yuhong Zhang
gr-qc/9303030
Quasi-Local Gravitational Energy
A dynamically preferred quasi-local definition of gravitational energy is given in terms of the Hamiltonian of a `2+2' formulation of general relativity. The energy is well-defined for any compact orientable spatial 2-surface, and depends on the fundamental forms only. The energy is zero for any surface in flat spaceti...
1993-03-26
2009-10-22
[ "gr-qc" ]
Sean A. Hayward
gr-qc/9303032
Geometrodynamics vs. Connection Dynamics
The purpose of this review is to describe in some detail the mathematical relationship between geometrodynamics and connection dynamics in the context of the classical theories of 2+1 and 3+1 gravity. I analyze the standard Einstein-Hilbert theory (in any spacetime dimension), the Palatini and Chern-Simons theories in ...
1993-03-26
2009-10-22
[ "gr-qc" ]
Joseph D. Romano
gr-qc/9303033
Scalar and Spinor Fields in Signature Changing Spacetimes
The propagation of scalar and spinor fields in a spacetime whose metric changes signature is analyzed. Recent work of Dray et al. on particle production from signature change for a (massless) scalar field is reviewed, and an attempt is made to extend their analysis to the case of a (massless) spin-half field. In contra...
1993-03-26
2009-10-22
[ "gr-qc" ]
Joseph D. Romano
gr-qc/9303027
The Newtonian Limit for Asymptotically Flat Solutions of the Vlasov-Einstein System
It is shown that there exist families of asymptotically flat solutions of the Einstein equations coupled to the Vlasov equation describing a collisionless gas which have a Newtonian limit. These are sufficiently general to confirm that for this matter model as many families of this type exist as would be expected on th...
1993-03-25
2009-10-22
[ "gr-qc" ]
Alan D. Rendall
gr-qc/9303028
Loop Variable Inequalities in Gravity and Gauge Theory
We point out an incompleteness of formulations of gravitational and gauge theories that use traces of holonomies around closed curves as their basic variables. It is shown that in general such loop variables have to satisfy certain inequalities if they are to give a description equivalent to the usual one in terms of l...
1993-03-25
2010-04-06
[ "gr-qc", "hep-th" ]
R. Loll
gr-qc/9303025
Radiation from a Uniformly Accelerated Charge and the Equivalence Principle
We argue that purely local experiments can distinguish a stationary charged particle in a static gravitational field from an accelerated particle in (gravity-free) Minkowski space. Some common arguments to the contrary are analyzed and found to rest on a misidentification of ``energy''.
1993-03-20
2008-02-03
[ "gr-qc", "astro-ph", "hep-ph", "hep-th" ]
Stephen Parrott
gr-qc/9303024
Generalized Symmetries of the Einstein Equations
We reformulate the symmetries of Gurses [Phys. Rev. Lett. 70, 367 (1993)] in a more abstract, more geometrical manner. The type (b) transformation of \gurses\ is related to a diffeomorphism of the differentiable manifold onto itself. The type (c) symmetry is replaced by a more general type (c-bar) symmetry that has the...
1993-03-20
2009-10-22
[ "gr-qc" ]
Frederick J. Ernst and Isidore Hauser
gr-qc/9303026
Unique determination of an inner product by adjointness relations in the algebra of quantum observables
It is shown that if a representation of a *-algebra on a vector space $V$ is an irreducible *-representation with respect to some inner product on $V$ then under appropriate technical conditions this property determines the inner product uniquely up to a constant factor. Ashtekar has suggested using the condition that ...
1993-03-20
2010-04-06
[ "gr-qc" ]
Alan D. Rendall
gr-qc/9303023
Inflationary Attractors and Perturbation Spectra in Generally Coupled Gravity
A generic outcome of theories with scalar-tensor coupling is the existence of inflationary attractors, either power-law or de Sitter. The fluctuations arising during this phase are Gaussian and their spectrum depends on the wavenumber $k$ according to the power-law $k^{1/(1-p)}$, where $p$ is the inflationary power-law...
1993-03-19
2009-10-22
[ "gr-qc", "astro-ph" ]
Luca Amendola, Diego Bellisai and Franco Occhionero, Rome Astronomical Observatory
gr-qc/9303022
Inconsistency between alternative approaches to Quantum Decoherence in special systems
We study the decoherence properties of a certain class of Markovian quantum open systems from both the Decohering Histories and Environment Induced Superselection paradigms. The class studied includes many familiar quantum optical cases. For this class, we show that there always exists a basis which leads to {\em exact...
1993-03-19
2007-05-23
[ "gr-qc" ]
J. Twamley
gr-qc/9303021
Non-Analytic Extension of the Kinnersley-Chitre Group for Colliding Plane Gravitational Waves. I
A program is outlined concerning the set of all solutions of the hyperbolic Ernst equation on a two-dimensional manifold whose underlying topological space is the same as the domain of all Ernst potentials for colliding plane gravitational wave pairs. The aim of the program is to construct and apply a non-trivial exten...
1993-03-17
2008-02-03
[ "gr-qc" ]
Isidore Hauser and Frederick J. Ernst
gr-qc/9303020
Clock Time and Entropy
Testable conditional probabilities appear to be restricted to single hypersurfaces (marvelous moments) and depend only on stationary observables. Observable evolution, such as a change of entropy, should be expressed as a dependence upon clock time, not upon inaccessible coordinate time.
1993-03-12
2008-02-03
[ "gr-qc" ]
Don N. Page
gr-qc/9303019
Loop Representations for 2+1 Gravity on a Torus
We study the loop representation of the quantum theory for 2+1 dimensional general relativity on a manifold, $M = {\cal T}^2 \times {\cal R}$, where ${\cal T}^2$ is the torus, and compare it with the connection representation for this system. In particular, we look at the loop transform in the part of the phase space w...
1993-03-12
2010-04-06
[ "gr-qc", "hep-th" ]
Donald Marolf
gr-qc/9303018
Wave Functions of the Induced 2D-Gravity
We consider the induced $2$d-gravity in the minisuperspace approach. The general solution to the Wheeler-DeWitt equation is given in terms of different kind of Bessel functions of purely real or imaginary orders. We study the properties of the corresponding probability distribution finding a kind of phase transition at...
1993-03-12
2011-04-20
[ "gr-qc" ]
J. Navarro-Salas, M. Navarro and V. Aldaya
gr-qc/9303017
Topologica Defects and Corrections to the Nambu Action
The effective action of a (1+2)-dimensional defect is obtained as an expansion in powers of the thickness.Considering non-straight solutions as the zero order term, the corrections to the Nambu action are found to depend on the curvature scalar and on the gaussian curvature .
1993-03-11
2008-11-26
[ "gr-qc" ]
Vanda Silveira and M.D. Maia (Universidade de Brasilia)
gr-qc/9303015
Bibliography of Publications related to Classical and Quantum Gravity in terms of the Ashtekar Variables
This bibliography attempts to give a comprehensive overview of all the literature related to the Ashtekar variables. The original version was compiled by Peter Huebner in 1989, and it has been subsequently updated by Gabriela Gonzalez and Bernd Bruegmann. Information about additional literature, new preprints, and espe...
1993-03-10
2008-02-03
[ "gr-qc", "hep-th" ]
Bernd Bruegmann
gr-qc/9303016
The Isaacson expansion in quantum cosmology
This paper is an application of the ideas of the Born-Oppenheimer (or slow/fast) approximation in molecular physics and of the Isaacson (or short-wave) approximation in classical gravity to the canonical quantization of a perturbed minisuperspace model of the kind examined by Halliwell and Hawking. Its aim is the clari...
1993-03-10
2010-11-01
[ "gr-qc" ]
Carsten Gundlach
gr-qc/9303014
Maxwell Fields in Spacetimes Admitting Non-Null Killing Vectors
We consider source-free electromagnetic fields in spacetimes possessing a non-null Killing vector field, $\xi^a$. We assume further that the electromagnetic field tensor, $F_{ab}$, is invariant under the action of the isometry group induced by $\xi^a$. It is proved that whenever the two potentials associated with the e...
1993-03-10
2010-04-06
[ "gr-qc" ]
Istvan Racz
gr-qc/9303013
Torsion and Nonmetricity in Scalar-Tensor Theories of Gravity
We show that the gravitational field equations derived from an action composed of i) an arbitrary function of the scalar curvature and other scalar fields plus ii) connection-independent kinetic and source terms, are identical whether one chooses nonmetricity to vanish and have non-zero torsion or vice versa.
1993-03-09
2010-04-06
[ "gr-qc" ]
Jean-paul Berthias and Bahman Shahid-Saless
gr-qc/9303012
Microcanonical Action and the Entropy of a Rotating Black Hole
The authors have recently proposed a ``microcanonical functional integral" representation of the density of quantum states of the gravitational field. The phase of this real--time functional integral is determined by a ``microcanonical" or Jacobi action, the extrema of which are classical solutions at fixed total energ...
1993-03-08
2007-05-23
[ "gr-qc", "astro-ph", "hep-th" ]
J. David Brown and James W. York
gr-qc/9303011
The Construction of Sorkin Triangulations
Some time ago, Sorkin (1975) reported investigations of the time evolution and initial value problems in Regge calculus, for one triangulation each of the manifolds $R*S^3$ and $R^4$. Here we display the simple, local characteristic of those triangulations which underlies the structure found by Sorkin, and emphasise it...
1993-03-05
2010-04-06
[ "gr-qc" ]
Philip Tuckey
gr-qc/9303010
The Extended Loop Group: An Infinite Dimensional Manifold Associated with the Loop Space
A set of coordinates in the non parametric loop-space is introduced. We show that these coordinates transform under infinite dimensional linear representations of the diffeomorphism group. An extension of the group of loops in terms of these objects is proposed. The enlarged group behaves locally as an infinite dimensi...
1993-03-04
2009-10-22
[ "gr-qc" ]
Cayetano Di Bartolo, Rodolfo Gambini and Jorge Griego
gr-qc/9303009
Conformal Fourth-Rank Gravity
We consider the consequences of describing the metric properties of space- time through a quartic line element $ds^4=G_{\mu\nu\lambda\rho}dx^\mu dx^\nu dx^\lambda dx^\rho$. The associated "metric" is a fourth-rank tensor $G_{\mu\nu\lambda\rho}$. We construct a theory for the gravitational field based on the fourth-rank...
1993-03-03
2007-05-23
[ "gr-qc" ]
Victor Tapia, A.L. Marrakchi and M. Cataldo
gr-qc/9303005
Motion and Trajectories of Particles Around Three-Dimensional Black Holes
The motion of relativistic particles around three dimensional black holes following the Hamilton-Jacobi formalism is studied. It follows that the Hamilton-Jacobi equation can be separated and reduced to quadratures in analogy with the four dimensional case. It is shown that: a) particles are trapped by the black hole i...
1993-03-02
2010-04-06
[ "gr-qc" ]
C. Farina, J. Gamboa and A. J. Segui-Santonja
gr-qc/9303008
No Superluminal Expansion of the Universe
The apparent superluminal growth in the size of a sufficiently large part of the universe can be ascribed to the special relativistic effect of time dilation.
1993-03-02
2007-05-23
[ "gr-qc" ]
Don N. Page
gr-qc/9303004
The Quantization of the Spacetime Geometry Generated by Planckian Energy Particles
We study the quantization of the curved spacetime created by ultrarelativistic particles at Planckian energies. We consider a minisuperspace model based on the classical shock wave metric generated by these particles, and for which the Wheeler - De Witt equation is solved exactly. The wave function of the geometry is a...
1993-03-02
2008-02-03
[ "gr-qc", "astro-ph", "hep-th" ]
C.O.Lousto and N.Sanchez
gr-qc/9303007
The Universality of Einstein Equations
It is shown that for a wide class of analytic Lagrangians which depend only on the scalar curvature of a metric and a connection, the application of the so--called ``Palatini formalism'', i.e., treating the metric and the connection as independent variables, leads to ``universal'' equations. If the dimension $n$ of spa...
1993-03-02
2010-12-13
[ "gr-qc", "hep-th" ]
M.Ferraris, M.Francaviglia and I.Volovich
gr-qc/9303006
General Laws of Black-Hole Dynamics
A general definition of a black hole is given, and general `laws of black-hole dynamics' derived. The definition involves something similar to an apparent horizon, a trapping horizon, defined as a hypersurface foliated by marginal surfaces of one of four non-degenerate types, described as future or past, and outer or i...
1993-03-02
2009-10-22
[ "gr-qc" ]
Sean A. Hayward
gr-qc/9303001
A Cosmological Theory without Singularities
A theory of gravitation is constructed in which all homogeneous and isotropic solutions are nonsingular, and in which all curvature invariants are bounded. All solutions for which curvature invariants approach their limiting values approach de Sitter space. The action for this theory is obtained by a higher derivative ...
1993-03-01
2009-10-22
[ "gr-qc", "astro-ph", "hep-th" ]
R. Brandenberger (Brown), V. Mukhanov (ETH Zuerich) and A. Sornborger (Brown)
gr-qc/9303003
String-Like Structures in Complex Kerr Geometry
The Kerr geometry is represented as being created by a source moving along an analytical complex world-line. The equivalence of this complex world-line and an Euclidean version of complex strings (hyperbolic strings) is discussed. It is shown that the complex Kerr source satisfies the corresponding string equations. Th...
1993-03-01
2007-05-23
[ "gr-qc", "hep-th" ]
A. Burinskii
gr-qc/9303002
The Scalar Field Equation in the Presence of Signature Change
We consider the (massless) scalar field on a 2-dimensional manifold with metric that changes signature from Lorentzian to Euclidean. Requiring a conserved momentum in the spatially homogeneous case leads to a particular choice of propagation rule. The resulting mix of positive and negative frequencies depends only on t...
1993-03-01
2016-08-31
[ "gr-qc", "hep-th" ]
Tevian Dray, Corinne A. Manogue, and Robin W. Tucker
gr-qc/9302035
A Pictorial History of Some Gravitational Instantons
Four-dimensional Euclidean spaces that solve Einstein's equations are interpreted as WKB approximations to wavefunctionals of quantum geometry. These spaces are represented graphically by suppressing inessential dimensions and drawing the resulting figures in perspective representation of three-dimensional space, some ...
1993-02-26
2008-02-03
[ "gr-qc", "hep-th" ]
Dieter Brill and Kay-Thomas Pirk
gr-qc/9302037
A Model of Topological Affine Gravity in Two Dimensions
A model of two--dimensional gravity with an action depending only on a linear connection is considered. This model is a topological one, in the sense that the classical action does not contain a metric or zweibein at all. A metric and an additional vector field are instead introduced in the process of solving equations...
1993-02-26
2019-08-17
[ "gr-qc", "hep-th" ]
M.Ferraris, M.Francaviglia and I.Volovich
gr-qc/9302036
Quantum Effects In Cosmology
Contents: Introduction. The Present State of the Universe. What Can We Expect From a Complete Cosmological Theory? An Overview of Quantum Effects in Cosmology. Parametric (Superadiabatic) Amplification of Classical Waves. Graviton Creation in the Inflationary Universe. Quantum States of a Harmonic Oscillato...
1993-02-26
2010-04-06
[ "gr-qc" ]
L.P. Grishchuk ( Physics Department, Washington University, St. Louis, U.S.A.)
gr-qc/9302034
On the Cosmology of Massive Vector Fields with SO(3) Global Symmetry
A relevant reference ([14]) has been added.
1993-02-23
2010-04-06
[ "gr-qc" ]
M.C. Bento, O. Bertolami, P.V. Moniz, J.M. Mourao and P.M. S\'a
gr-qc/9302033
Symmetries of the Einstein Equations
Generalized symmetries of the Einstein equations are infinitesimal transformations of the spacetime metric that formally map solutions of the Einstein equations to other solutions. The infinitesimal generators of these symmetries are assumed to be local, \ie at a given spacetime point they are functions of the metric a...
1993-02-23
2009-10-22
[ "gr-qc" ]
C. G. Torre and I. M. Anderson
gr-qc/9302029
Quantum and Thermal Fluctuations, Uncertainty Principle, Decoherence and Classicality*
We scrutize the commonly used criteria for classicality and examine their underlying issues. The two major issues we address here are that of decoherence and fluctuations. We borrow the insights gained in the study of the semiclassical limit of quantum cosmology to discuss the three criteria of classicality for a quant...
1993-02-22
2007-05-23
[ "gr-qc" ]
B. L. Hu and Yuhong Zhang
gr-qc/9302032
Do Black Holes Exist?
The problem of information loss in black hole formation and the associated violations of basic laws of physics, such as conservation of energy, causality and unitarity, are avoided in the nonsymmetric gravitational theory, if the NGT charge of a black hole and its mass satisfy an inequality that does not violate any kn...
1993-02-22
2007-05-23
[ "gr-qc" ]
J. W. Moffat
gr-qc/9302028
Karolyhazy's quantum space-time generates neutron star density in vacuum
By simple arguments, we have shown that Karolyhazy's model overestimates the quantum uncertainty of the space-time geometry and leads to absurd physical consequences. The given model can thus not account for gradual violation of quantum coherence and can not predict tiny experimental effects either.
1993-02-22
2008-11-26
[ "gr-qc" ]
L.Diosi and B.Lukacs
gr-qc/9302030
Critical Dynamics in the Early Universe
Methods and concepts for the study of phase transitions mediated by a time-dependent order-parameter field in curved spacetimes are discussed. A practical example is the derivation of an effective (quasi-)potential for the description of `slow-roll' inflation in the early universe. We first summarize our early results ...
1993-02-22
2010-04-06
[ "gr-qc" ]
B. L. Hu
gr-qc/9302031
Quantum Statistical Processes in the Early Universe
We show how the concept of quantum open system and the methods in non-equilibrium statistical mechanics can be usefully applied to studies of quantum statistical processes in the early universe. We first sketch how noise, fluctuation, dissipation and decoherence processes arise in a wide range of cosmological problems....
1993-02-22
2009-10-22
[ "gr-qc" ]
B. L. Hu
gr-qc/9302026
Minisuperspaces: Symmetries and Quantization
In several of the class A Bianchi models, minisuperspaces admit symmetries. It is pointed out that they can be used effectively to complete the Dirac quantization program. The resulting quantum theory provides a useful platform to investigate a number of conceptual and technical problems of quantum gravity.
1993-02-21
2007-05-23
[ "gr-qc" ]
Abhay Ashtekar, Ranjeet S. Tate and Claes Uggla
gr-qc/9302027
Minisuperspaces: Observables and Quantization
A canonical transformation is performed on the phase space of a number of homogeneous cosmologies to simplify the form of the scalar (or, Hamiltonian) constraint. Using the new canonical coordinates, it is then easy to obtain explicit expressions of Dirac observables, i.e.\ phase space functions which commute weakly wi...
1993-02-21
2009-07-10
[ "gr-qc" ]
Abhay Ashtekar, Ranjeet S. Tate and Claes Uggla
gr-qc/9302022
Symmetric solutions of Einstein-Yang-Mills equations
Symmetric gauge fields and invariant metrics in homogeneous spaces are found. Their use for finding exact solutions of the Einstein-Yang-Mills (EYM) equations is discussed.
1993-02-19
2016-08-14
[ "gr-qc" ]
J.M. Mour\~ao
gr-qc/9302023
Brill Waves
Brill waves are the simplest (non-trivial) solutions to the vacuum constraints of general relativity. They are also rich enough in structure to allow us believe that they capture, at least in part, the generic properties of solutions of the Einstein equations. As such, they deserve the closest attention. This article i...
1993-02-19
2007-05-23
[ "gr-qc" ]
Niall \'O Murchadha
gr-qc/9302025
Minisuperspace as a Quantum Open System
We trace the development of ideas on dissipative processes in chaotic cosmology and on minisuperspace quantum cosmology from the time Misner proposed them to current research. We show 1) how the effect of quantum processes like particle creation in the early universe can address the issues of the isotropy and homogenei...
1993-02-19
2007-05-23
[ "gr-qc" ]
B. L. Hu, Juan Pablo Paz and Sukanya Sinha
gr-qc/9302024
Mathematical Problems of Non-perturbative Quantum General Relativity
The purpose of these lectures is to discuss in some detail a new, non-perturbative approach to quantum gravity. I would like to present the basic ideas, outline the key results that have been obtained so far and indicate where we are headed and what the hopes are. The audience at this summer school had a diverse backgr...
1993-02-19
2007-05-23
[ "gr-qc", "hep-th" ]
Abhay Ashtekar
gr-qc/9302021
Fluctuation, Dissipation and Irreversibility in Cosmology
We discuss the appearance of time-asymmetric behavior in physical processes in cosmology and in the dynamics of the Universe itself. We begin with an analysis of the nature and origin of irreversibility in well-known physical processes such as dispersion, diffusion, dissipation and mixing, and make the distinction betw...
1993-02-18
2007-05-23
[ "gr-qc" ]
B. L. Hu
gr-qc/9302020
The Initial Value Problem in Light of Ashtekar's Variables
The form of the initial value constraints in Ashtekar's hamiltonian formulation of general relativity is recalled, and the problem of solving them is compared with that in the traditional metric variables. It is shown how the general solution of the four diffeomorphism constraints can be obtained algebraically provided...
1993-02-18
2007-05-23
[ "gr-qc" ]
R. Capovilla, J. Dell and T. Jacobson
gr-qc/9302019
A more accurate analytic calculation of the spectrum of cosmological perturbations produced during inflation
Formulae are derived for the spectra of scalar curvature perturbations and gravitational waves produced during inflation, special cases of which include power law inflation, natural inflation in the small angle approximation and inflation in the slow roll approximation.
1993-02-18
2008-11-26
[ "gr-qc", "astro-ph", "hep-ph" ]
E.D.Stewart and D.H.Lyth
gr-qc/9302018
Impossible Measurements on Quantum Fields
It is shown that the attempt to extend the notion of ideal measurement to quantum field theory leads to a conflict with locality, because (for most observables) the state vector reduction associated with an ideal measurement acts to transmit information faster than light. Two examples of such information-transfer are g...
1993-02-17
2008-02-03
[ "gr-qc", "hep-th" ]
Rafael D. Sorkin
gr-qc/9302017
Proof of the Generalized Second Law for Quasistationary Semiclassical Black Holes
A simple direct explicit proof of the generalized second law of black hole thermodynamics is given for a quasistationary semiclassical black hole.
1993-02-15
2010-11-01
[ "gr-qc" ]
Valery P. Frolov and Don N. Page
gr-qc/9302015
The quantum behavior of general time dependent quadratic systems linearly coupled to a bath
In this paper we solve for the quantum propagator of a general time dependent system quadratic in both position and momentum, linearly coupled to an infinite bath of harmonic oscillators. We work in the regime where the quantum optical master equation is valid. We map this master equation to a Schroedinger equation on ...
1993-02-11
2008-11-26
[ "gr-qc" ]
J. Twamley
gr-qc/9302014
Towards a Nonsingular Universe
A unified theory of all forces should be nonsingular. In such a unified theory, Einstein's general relativity will be a very low curvature effective theory. At larger curvatures, new terms will become important. The question then arises as to whether it is possible to construct an effective action for gravity which lea...
1993-02-11
2009-10-22
[ "gr-qc", "astro-ph", "hep-th" ]
Robert H. Brandenberger (Brown University)
gr-qc/9302016
Quantum Cosmology
An elementary review of quantum cosmology. (Talk given at Texas/Pascos 1992 at Berkeley)
1993-02-11
2009-10-22
[ "gr-qc" ]
Alexander Vilenkin
gr-qc/9302010
Cosmology with Nonminimal Derivative Couplings
We study a theory which generalizes the nonminimal coupling of matter to gravity by including derivative couplings. This leads to several interesting new dynamical phenomena in cosmology. In particular, the range of parameters in which inflationary attractors exist is greatly expanded. We also numerically integrate the...
1993-02-10
2009-10-22
[ "gr-qc" ]
Luca Amendola (Rome Astronomical Observatory)
gr-qc/9302012
Geometry of the 2+1 Black Hole
The geometry of the spinning black holes of standard Einstein theory in 2+1 dimensions, with a negative cosmological constant and without couplings to matter, is analyzed in detail. It is shown that the black hole arises from identifications of points of anti-de Sitter space by a discrete subgroup of $SO(2,2)$. The gen...
1993-02-10
2009-12-30
[ "gr-qc" ]
Maximo Banados, Marc Henneaux, Claudio Teitelboim, Jorge Zanelli
gr-qc/9302011
Finite, diffeomorphism invariant observables in quantum gravity
Two sets of spatially diffeomorphism invariant operators are constructed in the loop representation formulation of quantum gravity. This is done by coupling general relativity to an anti- symmetric tensor gauge field and using that field to pick out sets of surfaces, with boundaries, in the spatial three manifold. The ...
1993-02-10
2009-10-22
[ "gr-qc", "hep-th" ]
Lee Smolin
gr-qc/9302013
Decoherence of Correlation Histories
We use a $\lambda\Phi^4$ scalar quantum field theory to illustrate a new approach to the study of quantum to classical transition. In this approach, the decoherence functional is employed to assign probabilities to consistent histories defined in terms of correlations among the fields at separate points, rather than th...
1993-02-10
2007-05-23
[ "gr-qc" ]
E. Calzetta and B. L. Hu
gr-qc/9302008
The Structure of Naked Singularity in Self-similar Gravitational Collapse II
Generalizing the results of Joshi and Dwivedi in Commun.Math.Phys. 146, p.333 (1992), it is pointed out that strong curvature naked singularities could occur in the self-similar gravitational collapse of any form of matter satisfying the weak energy condition for the positivity of mass-energy density.
1993-02-09
2009-10-22
[ "gr-qc" ]
P.S.Joshi and I.H.Dwivedi
gr-qc/9302009
Towards the Theory of Stationary Universe
This talk presents some progress achieved in collaboration with A.Linde and D.Linde towards understanding the true nature of the global spatial structure of the Universe as well as the most general stationary characteristics of its time-dependent state with eternally growing total volume.
1993-02-09
2009-10-22
[ "gr-qc", "astro-ph", "hep-ph" ]
Arthur Mezhlumian
gr-qc/9302007
The renormalization group for non-renormalizable theories: Einstein gravity with a scalar field
We develop a renormalization-group formalism for non-renormalizable theories and apply it to Einstein gravity theory coupled to a scalar field with the Lagrangian $L=\sqrt{g} [R U(\phi)-{1/2} G(\phi) g^{\mu\nu} \partial_{\mu}\phi \partial_{\nu}\phi- V(\phi)]$, where $U(\phi), G(\phi)$ and $V(\phi)$ are arbitrary functi...
1993-02-08
2011-07-19
[ "gr-qc" ]
A.O.Barvinsky, A.Yu.Kamenshchik and I.P.Karmazin
gr-qc/9302004
Two-loop effective potential in quantum field theory in curved space-time
The method of the calculation of effective potential (in linear curvature approximation and at any loop) in massless gauge theory in curved space- time by the direct solution of RG equation is given.The closed expression for two-loop effective potential is obtained.Two-loop effective potential in scalar self-interactin...
1993-02-05
2016-08-31
[ "gr-qc" ]
S.D.Odintsov
gr-qc/9302005
On limits of spacetimes -- a coordinate-free approach
A coordinate-free approach to limits of spacetimes is developed. The limits of the Schwarzschild metric as the mass parameter tends to 0 or $\infty$ are studied, extending previous results. Besides the known Petrov type D and 0 limits, three vacuum plane-wave solutions of Petrov type N are found to be limits of the Sch...
1993-02-05
2010-04-06
[ "gr-qc", "astro-ph" ]
F. M. Paiva, M. J. Rebou\c{c}as and M. A. H. MacCallum
gr-qc/9302006
Quantum Theory of Black Holes
A solvable 2-dimensional conformally invariant midi-superspace model for black holes is obtained by imposing spherical symmetry in 4-dimensional conformally invariant Einstein gravity. The Wheeler-DeWitt equation for the theory is solved exactly to obtain the unique quantum wave functional for an isolated black hole wi...
1993-02-05
2009-12-30
[ "gr-qc", "hep-th" ]
J. Gegenberg and G. Kunstatter
gr-qc/9302003
Dynamics and Collision of Massive Shells in Curved Backgrounds
We analyse the dynamics of the collision of two spherical massive shells in a generally spherically symmetric background, obtaining an expression from the conservation law that imposes a constraint between the different parameters involved. We study the light-like limit and make some comparisons of the predictions of o...
1993-02-03
2010-04-06
[ "gr-qc", "astro-ph" ]
D. Nunez, H. P. de Oliveira, and J. Salim
gr-qc/9302002
Complex Numbers, Quantum Mechanics and the Beginning of Time
A basic problem in quantizing a field in curved space is the decomposition of the classical modes in positive and negative frequency. The decomposition is equivalent to a choice of a complex structure in the space of classical solutions. In our construction the real tunneling geometries provide the link between the thi...
1993-02-02
2009-10-07
[ "gr-qc" ]
G.W. Gibbons and H.J. Pohle
gr-qc/9302001
Singularity Free Inhomogeneous Cosmological Stiff Fluid Models
We present a singularity free class of inhomogeneous cylindrical universes filled with stiff perfect fluid $(\rho = p)$. Its matter free $ (\rho = 0)$ limit yield two distinct vacuum spacetimes which can be considered as analogues of Kasner solution for inhomogeneous singularity free spacetime.
1993-02-01
2007-05-23
[ "gr-qc" ]
L. K. Patel and N. Dadhich
gr-qc/9301024
Topological Defects in Gravitational Theories with Non Linear Lagrangians
The gravitational field of monopoles, cosmic strings and domain walls is studied in the quadratic gravitational theory $R+\alpha R^2$ with $\alpha |R|\ll 1$, and is compared with the result in Einstein's theory. The metric aquires modifications which correspond to a short range `Newtonian' potential for gauge cosmic st...
1993-02-01
2016-08-31
[ "gr-qc", "astro-ph", "hep-th" ]
J. Audretsch, A. Economou and C.O. Lousto
gr-qc/9301023
Avoiding degenerate coframes in an affine gauge approach to quantum gravity
In quantum models of gravity, it is surmized that configurations with degenerate coframes could occur during topology change of the underlying spacetime structure. However, the coframe is not the true Yang--Mills type gauge field of the translations, since it lacks the inhomogeneous gradient term in the gauge transform...
1993-01-29
2008-11-26
[ "gr-qc", "hep-th" ]
E.W. Mielke, J.D. McCrea, Y. Ne'eman, F.W. Hehl
gr-qc/9301022
An Anisotropic Wormhole:TUNNELLING in Time and Space
We discuss the structure of a gravitational euclidean instanton obtained through coupling of gravity to electromagnetism. Its topology at fixed $t$ is $S^1\times S^2$. This euclidean solution can be interpreted as a tunnelling to a hyperbolic space (baby universe) at $t=0$ or alternatively as a static wormhole that joi...
1993-01-27
2009-10-22
[ "gr-qc" ]
M. Cavaglia' V. de Alfaro and F. de Felice
gr-qc/9301021
Black Holes with a Generalized Gravitational Action
Microscopic black holes are sensitive to higher dimension operators in the gravitational action. We compute the influence of these operators on the Schwarzschild solution using perturbation theory. All (time reversal invariant) operators of dimension six are included (dimension four operators don't alter the Schwarzsch...
1993-01-26
2010-01-06
[ "gr-qc", "hep-th" ]
Ming Lu and Mark B. Wise
gr-qc/9301019
Comments on Closed Bianchi Models
We show several kinematical properties that are intrinsic to the Bianchi models with compact spatial sections. Especially, with spacelike hypersurfaces being closed, (A) no anisotropic expansion is allowed for Bianchi type V and VII(A\not=0), and (B) type IV and VI(A\not=0,1) does not exist. In order to show them, we p...
1993-01-25
2010-04-06
[ "gr-qc" ]
Y.Fujiwara, H.Ishihara and H.Kodama
gr-qc/9301020
On the configuration space topology in general relativity
The configuration-space topology in canonical General Relativity depends on the choice of the initial data 3-manifold. If the latter is represented as a connected sum of prime 3-manifolds, the topology receives contributions from all configuration spaces associated to each individual prime factor. There are by now stro...
1993-01-25
2007-05-23
[ "gr-qc" ]
Domenico Giulini
gr-qc/9301018
Jacobi's Action and the Density of States
The authors have introduced recently a ``microcanonical functional integral" which yields directly the density of states as a function of energy. The phase of the functional integral is Jacobi's action, the extrema of which are classical solutions at a given energy. This approach is general but is especially well suite...
1993-01-18
2008-02-03
[ "gr-qc", "hep-th" ]
J. David Brown and James W. York
gr-qc/9301017
The Origin of Time Asymmetry
It is argued that the observed Thermodynamic Arrow of Time must arise from the boundary conditions of the universe. We analyse the consequences of the no boundary proposal, the only reasonably complete set of boundary conditions that has been put forward. We study perturbations of a Friedmann model containing a massive...
1993-01-18
2009-10-22
[ "gr-qc", "astro-ph" ]
S.W. Hawking, R. Laflamme and G.W. Lyons
gr-qc/9301016
Time, measurement and information loss in quantum cosmology
An error in the gauge fixed quantization of section 3 is corrected. The result is a much simpler treatment of the clock field, leading to a simplification of the gauge fixed quantum theory and the treatment of the semiclassical limit.
1993-01-15
2008-02-03
[ "gr-qc", "hep-th" ]
Lee Smolin
gr-qc/9401012
A Proposal of Positive-Definite Local Gravitational Energy Density in General Relativity
We propose a 4-dimensional Kaluza-Klein approach to general relativity in the (2,2)-splitting of space-time using the double null gauge. The associated Lagrangian is equivalent to the Einstein-Hilbert Lagrangian, since it yields the same field equations as the E-H Lagrangian does. It is describable as a (1+1)-dimension...
1993-01-15
2007-05-23
[ "gr-qc" ]
J.H. Yoon
gr-qc/9301014
On Self-Dual Gravity I
(One typo corrected and one incorrect statement removed. Extra details on conserved quantities and symmetry algebras added).
1993-01-14
2009-10-22
[ "gr-qc", "hep-th" ]
James D.E. Grant
gr-qc/9301013
"Are Black Holes in Brans-Dicke Theory precisely the same as in General Relativity?"
We study a three-parameters family of solutions of the Brans-Dicke field equations. They are static and spherically symmetric. We find the range of parameters for which this solution represents a black hole different from the Schwarzschild one. We find a subfamily of solutions which agrees with experiments and observat...
1993-01-14
2010-11-01
[ "gr-qc", "astro-ph", "hep-th" ]
M.Campanelli and C.O.Lousto
gr-qc/9301015
A Positive Mass Theorem Based on the Focusing and Retardation of Null Geodesics
A positive mass theorem for General Relativity Theory is proved. The proof is 4-dimensional in nature, and relies completely on arguments pertaining to causal structure, the basic idea being that positive energy-density focuses null geodesics, and correspondingly retards them, whereas a negative total mass would advanc...
1993-01-14
2008-02-03
[ "gr-qc", "hep-th" ]
R.Penrose, R.D. Sorkin, and E. Woolgar
gr-qc/9301012
Massive Spin-5/2 Fields Coupled to Gravity: Tree-Level Unitarity vs. the Equivalence Principle
I show that the gravitational scattering amplitudes of a spin-5/2 field with mass $m\ll M_{Pl}$ violate tree-level unitarity at energies $\sqrt{s}\approx\sqrt{mM_{Pl}}$ if the coupling to gravity is minimal. Unitarity up to energies $\sqrt{s}\approx M_{Pl}$ is restored by adding a suitable non-minimal term, which gives...
1993-01-14
2009-10-22
[ "gr-qc", "hep-th" ]
Massimo Porrati
gr-qc/9301011
The Reduction of the State Vector and Limitations on Measurement in the Quantum Mechanics of Closed Systems
Measurement is a fundamental notion in the usual approximate quantum mechanics of measured subsystems. Probabilities are predicted for the outcomes of measurements. State vectors evolve unitarily in between measurements and by reduction of the state vector at measurements. Probabilities are computed by summing the squa...
1993-01-13
2014-01-14
[ "gr-qc", "hep-th", "quant-ph" ]
James B. Hartle
gr-qc/9301010
Entropy Production in the Cosmological Amplification of the Vacuum Fluctuations
We estimate the entropy associated to a background of squeezed cosmic gravitons, and we argue that the process of cosmological pair production from the vacuum may explain the large amount of entropy of our present universe.
1993-01-12
2009-10-22
[ "gr-qc", "hep-th" ]
M.Gasperini and M.Giovannini
gr-qc/9301008
What is the True Description of Charged Black Holes?
If string theory describes nature, then charged black holes are not described by the Reissner-Nordstrom solution. This solution must be modified to include a massive dilaton. In the limit of vanishing dilaton mass, the new solution can be found by a generalization of the Harrison transformation for the Einstein-Maxwell...
1993-01-12
2007-05-23
[ "gr-qc", "hep-th" ]
Gary T. Horowitz
gr-qc/9301009
Cosmology, Oscillating Physics and Oscilllating Biology
According to recent reports there is an excess correlation and an apparent regularity in the galaxy one-dimensional polar distribution with a characteristic scale of 128 $h^{-1}$ Mpc. This aparent spatial periodicity can be naturally explained by a time oscillation of the gravitational constant $G$. On the other hand, ...
1993-01-11
2010-11-01
[ "gr-qc" ]
Pablo Sisterna and Hector Vucetich
gr-qc/9301007
Decoherence Functional and Probability Interpretation
We confirm that the diagonal elements of the Gell-Mann and Hartle's decoherence decoherence functional are equal to the relative frequencies of the results of many identical experiments, when a set of alternative histories decoheres. We consider both cases of the pure and mixed initial states.
1993-01-09
2009-10-22
[ "gr-qc" ]
Yoshiaki Ohkuwa
gr-qc/9301006
Real Tunneling Solutions and the Hartle-Hawking Wave Function
A real tunneling solution is an instanton for the Hartle-Hawking path integral with vanishing extrinsic curvature (vanishing ``momentum'') at the boundary. Since the final momentum is fixed, its conjugate cannot be specified freely; consequently, such an instanton will contribute to the wave function at only one or a f...
1993-01-08
2010-04-28
[ "gr-qc", "hep-th" ]
S. Carlip
gr-qc/9301005
Time Symmetric Quantum Cosmology and Our Universe
We investigate the time neutral formulation of quantum cosmology of Gell-Mann and Hartle. In particular we study the proposal discussed by them that our Universe corresponds to the time symmetric decoherence functional with initial and final density matrix of low entropy. We show that our Universe does not correspond t...
1993-01-08
2010-04-06
[ "gr-qc" ]
Raymond Laflamme
gr-qc/9301004
On the Definition of Decoherence
We examine the relationship between the decoherence of quantum-mechanical histories of a closed system (as discussed by Gell-Mann and Hartle) and environmentally-induced diagonalization of the density operator for an open system. We study a definition of decoherence which incorporates both of these ideas, and show that...
1993-01-07
2009-10-22
[ "gr-qc", "hep-th" ]
J. Finkelstein
gr-qc/9301002
Event horizons and apparent horizons in spherically symmetric geometries
Spherical configurations that are very massive must be surrounded by apparent horizons. These in turn, when placed outside a collapsing body, must propagate outward with a velocity equal to the velocity of radially outgoing photons. That proves, within the framework of (1+3) formalism and without resorting to the Birkh...
1993-01-06
2014-11-17
[ "gr-qc" ]
Edward Malec
gr-qc/9301003
Observing binary inspiral in gravitational radiation: One interferometer
We investigate the sensitivity of individual LIGO/VIRGO-like interferometers and the precision with which they can determine the characteristics of an inspiralling binary system. Since the two interferometers of the LIGO detector share nearly the same orientation, their joint sensitivity is similar to that of a single,...
1993-01-06
2009-10-22
[ "gr-qc", "astro-ph" ]
Lee Samuel Finn and David F. Chernoff
gr-qc/9301001
Bianchi Cosmological Models and Gauge Symmetries
We analyze carefully the problem of gauge symmetries for Bianchi models, from both the geometrical and dynamical points of view. Some of the geometrical definitions of gauge symmetries (=``homogeneity preserving diffeomorphisms'') given in the literature do not incorporate the crucial feature that local gauge transform...
1993-01-05
2010-04-06
[ "gr-qc" ]
Olivier Coussaert and Marc Henneaux
hep-lat/9312088
The Isgur-Wise Function: A Lattice Determination from Pseudoscalar --> Pseudoscalar Form Factors
Form factors for pseudoscalar --> pseudoscalar decays of heavy-light mesons are found in quenched lattice QCD with heavy-quark masses in the range of approximately 1-2 GeV. The Isgur-Wise function, $\xi(\omega)$, is extracted from these form factors. Results are in good agreement with $\xi(\omega)$ derived from CLEO me...
1993-12-30
2010-11-01
[ "hep-lat" ]
UKQCD Collaboration, James N. Simone
hep-lat/9312087
A Magnetic Monopole in Pure SU(2) Gauge Theory
The magnetic monopole in euclidean pure SU(2) gauge theory is investigated using a background field method on the lattice. With Monte Carlo methods we study the mass of the monopole in the full quantum theory. The monopole background under the quantum fluctuations is induced by imposing fixed monopole boundary cond...
1993-12-29
2009-10-22
[ "hep-lat", "hep-th" ]
J. Smit and A.J. Van Der Sijs
hep-lat/9312085
A definition of the running coupling constant in a twisted SU(2) lattice gauge theory
We propose a definition of the running coupling constant in a SU(2) lattice gauge theory with twisted boundary conditions. It is based on the correlation of Polyakov loops extended in a twisted direction at a distance which is a fixed fraction of the totale lattice size. We make the perturbative calculation which conne...
1993-12-28
2009-10-22
[ "hep-lat" ]
G.M. de Divitiis, R. Frezzotti, M. Guagnelli and R. Petronzio
hep-lat/9312086
Heavy-light and light-light weak matrix elements on the lattice
I review recent developments in lattice weak matrix element calculations. I focus on on $f_B$ (both with propagating quarks and in the static limit for the $b$ quark), semi-leptonic form factors for $D$ meson decay, form factors for $B \to K^* \gamma$, and $B_K$. [Review presented at Lattice '93]
1993-12-28
2009-10-22
[ "hep-lat", "hep-ph" ]
Claude Bernard