607 research outputs found
Spacetimes with Longitudinal and Angular Magnetic Fields in Third Order Lovelock Gravity
We obtain two new classes of magnetic brane solutions in third order Lovelock
gravity. The first class of solutions yields an -dimensional spacetime
with a longitudinal magnetic field generated by a static source. We generalize
this class of solutions to the case of spinning magnetic branes with one or
more rotation parameters. These solutions have no curvature singularity and no
horizons, but have a conic geometry. For the spinning brane, when one or more
rotation parameters are nonzero, the brane has a net electric charge which is
proportional to the magnitude of the rotation parameters, while the static
brane has no net electric charge. The second class of solutions yields a
pacetime with an angular magnetic field. These solutions have no curvature
singularity, no horizon, and no conical singularity. Although the second class
of solutions may be made electrically charged by a boost transformation, the
transformed solutions do not present new spacetimes. Finally, we use the
counterterm method in third order Lovelock gravity and compute the conserved
quantities of these spacetimes.Comment: 15 pages, no figur
Magnetic Branes in -dimensional Einstein-Maxwell-dilaton gravity
We construct two new classes of spacetimes generated by spinning and
traveling magnetic sources in -dimensional Einstein-Maxwell-dilaton
gravity with Liouville-type potential. These solutions are neither
asymptotically flat nor (A)dS. The first class of solutions which yields a
-dimensional spacetime with a longitudinal magnetic field and
rotation parameters have no curvature singularity and no horizons, but have a
conic geometry. We show that when one or more of the rotation parameters are
nonzero, the spinning branes has a net electric charge that is proportional to
the magnitude of the rotation parameters. The second class of solutions yields
a static spacetime with an angular magnetic field, and have no curvature
singularity, no horizons, and no conical singularity. Although one may add
linear momentum to the second class of solutions by a boost transformation, one
does not obtain a new solution. We find that the net electric charge of these
traveling branes with one or more nonzero boost parameters is proportional to
the magnitude of the velocity of the branes. We also use the counterterm method
and calculate the conserved quantities of the solutions.Comment: 15 pages, the last version to appear in PR
Nonlocality in kinetic roughening
We propose a phenomenological equation to describe kinetic roughening of a
growing surface in presence of long range interactions. The roughness of the
evolving surface depends on the long range feature, and several distinct
scenarios of phase transitions are possible. Experimental implications are
discussed.Comment: Replaced with the published version (Phys. Rev. Lett 79, 2502
(1997)). Eq. 1 written in a symmetrical form, references update
Magnetic Strings in Dilaton Gravity
First, I present two new classes of magnetic rotating solutions in
four-dimensional Einstein-Maxwell-dilaton gravity with Liouville-type
potential. The first class of solutions yields a 4-dimensional spacetime with a
longitudinal magnetic field generated by a static or spinning magnetic string.
I find that these solutions have no curvature singularity and no horizons, but
have a conic geometry. In these spacetimes, when the rotation parameter does
not vanish, there exists an electric field, and therefore the spinning string
has a net electric charge which is proportional to the rotation parameter. The
second class of solutions yields a spacetime with an angular magnetic field.
These solutions have no curvature singularity, no horizon, and no conical
singularity. The net electric charge of the strings in these spacetimes is
proportional to their velocities. Second, I obtain the ()-dimensional
rotating solutions in Einstein-dilaton gravity with Liouville-type potential. I
argue that these solutions can present horizonless spacetimes with conic
singularity, if one chooses the parameters of the solutions suitable. I also
use the counterterm method and compute the conserved quantities of these
spacetimes.Comment: 16 pages, no figure, references added, some minor correction
Vicinal Surfaces, Fractional Statistics and Universality
We propose that the phases of all vicinal surfaces can be characterized by
four fixed lines, in the renormalization group sense, in a three-dimensional
space of coupling constants. The observed configurations of several Si surfaces
are consistent with this picture. One of these fixed lines also describes
one-dimensional quantum particles with fractional exclusion statistics. The
featureless steps of a vicinal surface can therefore be thought of as a
realization of fractional-statistics particles, possibly with additional
short-range interactions.Comment: 6 pages, revtex, 3 eps figures. To appear in Physical Review Letters.
Reference list properly arranged. Caption of Fig. 1 slightly reworded. Fig 3
(in color) is not part of the paper. It complements Fig.
Counterterm Method in Lovelock Theory and Horizonless Solutions in Dimensionally Continued Gravity
In this paper we, first, generalize the quasilocal definition of the stress
energy tensor of Einstein gravity to the case of Lovelock gravity, by
introducing the tensorial form of surface terms that make the action
well-defined. We also introduce the boundary counterterm that removes the
divergences of the action and the conserved quantities of the solutions of
Lovelock gravity with flat boundary at constant and . Second, we obtain
the metric of spacetimes generated by brane sources in dimensionally continued
gravity through the use of Hamiltonian formalism, and show that these solutions
have no curvature singularity and no horizons, but have conic singularity. We
show that these asymptotically AdS spacetimes which contain two fundamental
constants are complete. Finally we compute the conserved quantities of these
solutions through the use of the counterterm method introduced in the first
part of the paper.Comment: 15 pages, references added, typos correcte
Ground State Wave Function of the Schr\"odinger Equation in a Time-Periodic Potential
Using a generalized transfer matrix method we exactly solve the Schr\"odinger
equation in a time periodic potential, with discretized Euclidean space-time.
The ground state wave function propagates in space and time with an oscillating
soliton-like wave packet and the wave front is wedge shaped. In a statistical
mechanics framework our solution represents the partition sum of a directed
polymer subjected to a potential layer with alternating (attractive and
repulsive) pinning centers.Comment: 11 Pages in LaTeX. A set of 2 PostScript figures available upon
request at [email protected] . Physical Review Letter
Magnetic Branes Supported by Nonlinear Electromagnetic Field
Considering the nonlinear electromagnetic field coupled to Einstein gravity
in the presence of cosmological constant, we obtain a new class of
-dimensional magnetic brane solutions. This class of solutions yields a
spacetime with a longitudinal nonlinear magnetic field generated by a static
source. These solutions have no curvature singularity and no horizons but have
a conic geometry with a deficit angle . We investigate the effects
of nonlinearity on the metric function and deficit angle and also find that for
the special range of the nonlinear parameter, the solutions are not asymptotic
AdS. We generalize this class of solutions to the case of spinning magnetic
solutions, and find that when one or more rotation parameters are nonzero, the
brane has a net electric charge which is proportional to the magnitude of the
rotation parameters. Then, we use the counterterm method and compute the
conserved quantities of these spacetimes. Finally, we obtain a constrain on the
nonlinear parameter, such that the nonlinear electromagnetic field is
conformally invariant.Comment: 15 pages, one eps figur
Scaling limit of vicious walks and two-matrix model
We consider the diffusion scaling limit of the one-dimensional vicious walker
model of Fisher and derive a system of nonintersecting Brownian motions. The
spatial distribution of particles is studied and it is described by use of
the probability density function of eigenvalues of Gaussian random
matrices. The particle distribution depends on the ratio of the observation
time and the time interval in which the nonintersecting condition is
imposed. As is going on from 0 to 1, there occurs a transition of
distribution, which is identified with the transition observed in the
two-matrix model of Pandey and Mehta. Despite of the absence of matrix
structure in the original vicious walker model, in the diffusion scaling limit,
accumulation of contact repulsive interactions realizes the correlated
distribution of eigenvalues in the multimatrix model as the particle
distribution.Comment: REVTeX4, 12 pages, no figure, minor corrections made for publicatio
Cosmological solutions, p-branes and the Wheeler-DeWitt equation
The low energy effective actions which arise from string theory or M-theory
are considered in the cosmological context, where the graviton, dilaton and
antisymmetric tensor field strengths depend only on time. We show that previous
results can be extended to include cosmological solutions that are related to
the E_N Toda equations. The solutions of the Wheeler-DeWitt equation in
minisuperspace are obtained for some of the simpler cosmological models by
introducing intertwining operators that generate canonical transformations
which map the theories into free theories. We study the cosmological properties
of these solutions, and also briefly discuss generalised Brans-Dicke models in
our framework. The cosmological models are closely related to p-brane solitons,
which we discuss in the context of the E_N Toda equations. We give the explicit
solutions for extremal multi-charge (D-3)-branes in the truncated system
described by the D_4 =O(4,4) Toda equations.Comment: 11 pages (2-column), Revte
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