150 research outputs found
Gauge Theory of Relativistic Membranes
In this paper we show that a relativistic membrane admits an equivalent
representation in terms of the Kalb-Ramond gauge field
encountered in string theory.
By `` equivalence '' we mean the following: if is a solution of the
classical equations of motion derived from the Dirac-Nambu-Goto action, then it
is always possible to find a differential form of {\it rank three}, satisfying
Maxwell-type equations. The converse proposition is also true. In the first
part of the paper, we show that a relativistic membrane, regarded as a
mechanical system, admits a Hamilton-Jacobi formulation in which the H-J
function describing a family of classical membrane histories is given by
. In the second part of the
paper, we introduce a {\it new} lagrangian of the Kalb-Ramond type which
provides a {\it first order} formulation for both open and closed membranes.
Finally, for completeness, we show that such a correspondence can be
established in the very general case of a p-brane coupled to gravity in a
spacetime of arbitrary dimensionality.Comment: 35 pages, PHYZZX, UTS-DFT-92-
Conformal p-branes as a Source of Structure in Spacetime
We discuss a model of a conformal p-brane interacting with the world volume
metric and connection. The purpose of the model is to suggest a mechanism by
which gravity coupled to p-branes leads to the formation of structure rather
than homogeneity in spacetime. Furthermore, we show that the formation of
structure is accompanied by the appearance of a multivalued cosmological
constant, i.e., one which may take on different values in different domains, or
cells, of spacetime. The above results apply to a broad class of non linear
gravitational lagrangians as long as metric and connection on the p-brane
manifold are treated as independent variables.Comment: 10 pages, ReVTeX, no figure
Membrane Pregeometry and the Vanishing of the Cosmological Constant
We suggest a model of induced gravity in which the fundamental object is a
relativistic {\it membrane} minimally coupled to a background metric and to an
external three index gauge potential. We compute the low energy limit of the
two-loop effective action as a power expansion in the surface tension. A
generalized bootstrap hypothesis is made in order to identify the physical
metric and gauge field with the lowest order terms in the expansion of the
vacuum average of the composite operators conjugate to the background fields.
We find that the large distance behaviour of these classical fields is
described by the Einstein action with a cosmological term plus a Maxwell type
action for the gauge potential. The Maxwell term enables us to apply the
Hawking-Baum argument to show that the physical cosmological constant is
``~probably~'' zero.Comment: 14 pages, no figures, phyzzx macr
Membrane Vacuum as a Type II Superconductor
We study a functional field theory of membranes coupled to a rank--three
tensor gauge potential. We show that gauge field radiative corrections lead to
membrane condensation which turns the gauge field into a {\it massive spin--0
field}. This is the Coleman--Weinberg mechanism for {\it membranes}. An analogy
is also drawn with a type--II superconductor. The ground state of the system
consists of a two--phase medium in which the superconducting background
condensate is ``pierced'' by four dimensional domains, or ``bags'', of non
superconducting vacuum. Bags are bounded by membranes whose physical thickness
is of the order of the inverse mass acquired by the gauge field.Comment: 14 pages, no figures, LaTeX; to be Published on In.J.Mod.Phys.B
Umezawa Memorial Issu
Particle Propagator in Elementary Quantum Mechanics: a New Path Integral Derivation
This paper suggests a new way to compute the path integral for simple quantum
mechanical systems. The new algorithm originated from previous research in
string theory. However, its essential simplicity is best illustrated in the
case of a free non relativistic particle, discussed here, and can be
appreciated by most students taking an introductory course in Quantum
Mechanics. Indeed, the emphasis is on the role played by the {\it entire family
of classical trajectories} in terms of which the path integral is computed
exactly using a functional representation of the Dirac delta-distribution. We
argue that the new algorithm leads to a deeper insight into the connection
between classical and quantum systems, especially those encountered in high
energy physics.Comment: LaTex uses iopams package, 15pages, no figures, in print on Euro.J.of
Phy
Vacuum Bubbles Nucleation and Dark Matter Production through Gauge Symmetry Rearrangement
Modern particle physics and cosmology support the idea that a background of
invisible material pervades the whole universe, and identify in the cosmic
vacuum the ultimate source of matter-energy, both seen and unseen. Within the
framework of the theory of fundamental relativistic membranes, we suggest a
self-consistent, vacuum energy-driven mechanism for dark matter creation
through gauge symmetry rearrangement.Comment: 22pages, RevTeX, no figures; accepted for publication in Phys.Rev.
Effective dynamics of self-gravitating extended objects
We introduce an effective Lagrangian which describes the classical and
semiclassical dynamics of spherically symmetric, self-gravitating objects that
may populate the Universe at large and small (Planck) scale. These include
wormholes, black holes and inflationary bubbles. We speculate that such objects
represent some possible modes of fluctuation in the primordial spacetime foam
out of which our universe was born. Several results obtained by different
methods are encompassed and reinterpreted by our effective approach. As an
example, we discuss: i) the gravitational nucleation coefficient for a pair of
Minkowski bubbles, and ii) the nucleation coefficient of an inflationary vacuum
bubble in a Minkowski backgroundComment: 13 pages, no figures, ReVTe
Classical and Quantum Shell Dynamics, and Vacuum Decay
Following a minisuperspace approach to the dynamics of a spherically
symmetric shell, a reduced Lagrangian for the radial degree of freedom is
derived directly from the Einstein-Hilbert action. The key feature of this new
Lagrangian is its invariance under time reparametrization. Indeed, all
classical and quantum dynamics is encoded in the Hamiltonian constraint that
follows from that invariance. Thus, at the classical level, we show that the
Hamiltonian constraint reproduces, in a simple gauge, Israel's matching
condition which governs the evolution of the shell. In the quantum case, the
vanishing of the Hamiltonian (in a weak sense), is interpreted as the
Wheeler-DeWitt equation for the physical states, in analogy to the
corresponding case in quantum cosmology. Using this equation, quantum tunneling
through the classical barrier is then investigated in the WKB approximation,
and the connection to vacuum decay is elucidated.Comment: 36 pages, ReVTeX, 10 Figs. in postscript format, in print on Class.&
Quant.Gra
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