698 research outputs found
The Physical Projector and Topological Quantum Field Theories: U(1) Chern-Simons Theory in 2+1 Dimensions
The recently proposed physical projector approach to the quantisation of
gauge invariant systems is applied to the U(1) Chern-Simons theory in 2+1
dimensions as one of the simplest examples of a topological quantum field
theory. The physical projector is explicitely demonstrated to be capable of
effecting the required projection from the initially infinite number of degrees
of freedom to the finite set of gauge invariant physical states whose
properties are determined by the topology of the underlying manifold.Comment: 24 pages, no figures, plain LaTeX file; one more reference added.
Final version to appear in Jour. Phys.
Half-monopoles and half-vortices in the Yang-Mills theory
It is demonstrated that there are smooth Yang-Mills potentials which
correspond to monopoles and vortices of one-half winding number. They are the
generic configurations, in contrast to the integral winding number
configurations like the 't Hooft-Polyakov monopole.Comment: 8 pages, 3 figures; references adde
Finite Euler Hierarchies And Integrable Universal Equations
Recent work on Euler hierarchies of field theory Lagrangians iteratively
constructed {}from their successive equations of motion is briefly reviewed. On
the one hand, a certain triality structure is described, relating arbitrary
field theories, {\it classical\ts} topological field theories -- whose
classical solutions span topological classes of manifolds -- and
reparametrisation invariant theories -- generalising ordinary string and
membrane theories. On the other hand, {\it finite} Euler hierarchies are
constructed for all three classes of theories. These hierarchies terminate with
{\it universal\ts} equations of motion, probably defining new integrable
systems as they admit an infinity of Lagrangians. Speculations as to the
possible relevance of these theories to quantum gravity are also suggested.Comment: (replaces previous unprintable version corrupted mailer) 13 p.,
(Plain TeX), DTP-92/3
Hamiltonian Analysis of the Higgs Mechanism for Graviton
In this paper we perform the canonical description of the Higgs mechanism for
gravity and provide the Hamiltonian definition of the massive gravities.Comment: 18 page
Relativistic Quarkonia from Anisotropic Lattices
We report on new results for the spectrum of quarkonia using a fully
relativistic approach on anisotropic lattices with quark masses in the range
from strange to bottom. A fine temporal discretisation also enables us to
resolve excitations high above the ground state. In particular we studied the
mass dependence and scaling of hybrid states.Comment: 4 pages, 5 figures. Lattice 2000 (Heavy Quark Physics
Improved Determination of the Mass of the Light Hybrid Meson From QCD Sum Rules
We calculate the next-to-leading order (NLO) -corrections to the
contributions of the condensates and in the
current-current correlator of the hybrid current
g\barq(x)\gamma_{\nu}iF_{\mu\nu}^aT^aq(x) using the external field method in
Feynman gauge. After incorporating these NLO contributions into the Laplace
sum-rules, the mass of the = light hybrid meson is recalculated
using the QCD sum rule approach. We find that the sum rules exhibit enhanced
stability when the NLO -corrections are included in the sum rule
analysis, resulting in a light hybrid meson mass of approximately 1.6
GeV.Comment: revtex4, 10 pages, 7 eps figures embedded in manuscrip
The electromagnetic effects in isospin symmetry breakings of q{\bar q} systems
The isospin symmetry breakings of q{\bar q} are investigated in the QCD sum
rule method. The electromagnetic effects are evaluated following the procedure
requiring that the electromagnetic effects for charged meson be gauge
invariant. We find that the electromagnetic effects are also dominant in the
isospin violations of rho meson, which have been shown to be the case in the
mass splittings of pions. The numerical results for the difference of pion
decay constants and the masses of rho mesons are presented, which are
consistent with the data.Comment: To appear in Phys. Rev. D (1997
On the quantum mechanics of M(atrix) theory
We present a study of M(atrix) theory from a purely canonical viewpoint. In
particular, we identify free particle asymptotic states of the model
corresponding to the supergraviton multiplet of eleven dimensional
supergravity. These states have a natural interpretation as excitations in the
flat directions of the matrix model potential. Furthermore, we provide the
split of the matrix model Hamiltonian into a free part describing the free
propagation of these particle states along with the interaction Hamiltonian
describing their interactions. Elementary quantum mechanical perturbation
theory then yields an effective potential for these particles as an expansion
in their inverse separation. Remarkably we find that the leading velocity
independent terms of the effective potential cancel in agreement with the fact
that there is no force between stationary D0 branes. The scheme we present
provides a framework in which one can perturbatively compute the M(atrix)
theory result for the eleven dimensional supergraviton S matrix.Comment: 28 pages, Latex2
Linearisation of Universal Field Equations
The Universal Field Equations, recently constructed as examples of higher
dimensional dynamical systems which admit an infinity of inequivalent
Lagrangians are shown to be linearised by a Legendre transformation. This
establishes the conjecture that these equations describe integrable systems.
While this construction is implicit in general, there exists a large class of
solutions for which an explicit form may be written.Comment: 11pp., DTP-92/47, NI-92/01
Finite to infinite steady state solutions, bifurcations of an integro-differential equation
We consider a bistable integral equation which governs the stationary
solutions of a convolution model of solid--solid phase transitions on a circle.
We study the bifurcations of the set of the stationary solutions as the
diffusion coefficient is varied to examine the transition from an infinite
number of steady states to three for the continuum limit of the
semi--discretised system. We show how the symmetry of the problem is
responsible for the generation and stabilisation of equilibria and comment on
the puzzling connection between continuity and stability that exists in this
problem
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