2,640 research outputs found
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 independently of their energy and angular momentum, b) matter
alway falls to the centre of the black hole and cannot understake a motion with
stables orbits as in four dimensions. For the extreme values of the angular
momentum of the black hole, we were able to find exact solutions of the
equations of motion and trajectories of a test particle.Comment: Plain TeX, 9pp, IPNO-TH 93/06, DFTUZ 93/0
Exotic galilean symmetry and the Hall effect
The ``Laughlin'' picture of the Fractional Quantum Hall effect can be derived
using the ``exotic'' model based on the two-fold centrally-extended planar
Galilei group. When coupled to a planar magnetic field of critical strength
determined by the extension parameters, the system becomes singular, and
``Faddeev-Jackiw'' reduction yields the ``Chern-Simons'' mechanics of Dunne,
Jackiw, and Trugenberger. The reduced system moves according to the Hall law.Comment: Talk given by P. A. Horvathy at the Joint APCTP- Nankai Symposium.
Tianjin (China), Oct.2001. To appear in the Proceedings, to be published by
Int. Journ. Mod. Phys. B. 7 pages, LaTex, IJMPB format. no figure
The Landau problem and noncommutative quantum mechanics
The conditions under which noncommutative quantum mechanics and the Landau
problem are equivalent theories is explored. If the potential in noncommutative
quantum mechanics is chosen as with defined in the
text, then for the value (that
measures the noncommutative effects of the space), the Landau problem and
noncommutative quantum mechanics are equivalent theories in the lowest Landau
level. For other systems one can find differents values for
and, therefore, the possible bounds for should be searched in
a physical independent scenario. This last fact could explain the differents
bounds for found in the literature.Comment: This a rewritten and corrected version of our previous preprint
hep-th/010517
On the Initial Singularity Problem in Two Dimensional Quantum Cosmology
The problem of how to put interactions in two-dimensional quantum gravity in
the strong coupling regime is studied. It shows that the most general
interaction consistent with this symmetry is a Liouville term that contain two
parameters satisfying the algebraic relation in order to assure the closure of the diffeomorphism algebra. The model is
classically soluble and it contains as general solution the temporal
singularity. The theory is quantized and we show that the propagation amplitude
fall tozero in . This result shows that the classical singularities
are smoothed by quantum effects and the bing-bang concept could be considered
as a classical extrapolation instead of a physical concept.Comment: 9pp, Revtex 3.0. New references added. To appear in Phys. Rev.
Noncommutative Quantum Mechanics: The Two-Dimensional Central Field
Quantum mechanics in a noncommutative plane is considered. For a general two
dimensional central field, we find that the theory can be perturbatively solved
for large values of the noncommutative parameter () and explicit
expressions for the eigenstates and eigenvalues are given. The Green function
is explicitly obtained and we show that it can be expressed as an infinite
series. For polynomial type potentials, we found a smooth limit for small
values of and for non-polynomial ones this limit is necessarily
abrupt. The Landau problem, as a limit case of a noncommutative system, is also
considered.Comment: new references adde
Aharonov-Casher effect for spin one particles in a noncommutative space
In this work the Aharonov-Casher (AC) phase is calculated for spin one
particles in a noncommutative space. The AC phase has previously been
calculated from the Dirac equation in a noncommutative space using a gauge-like
technique [17]. In the spin-one, we use kemmer equation to calculate the phase
in a similar manner. It is shown that the holonomy receives non-trivial
kinematical corrections. By comparing the new result with the already known
spin 1/2 case, one may conjecture a generalized formula for the corrections to
holonomy for higher spins.Comment: 9 page
Radiative processes as a condensation phenomenon and the physical meaning of deformed canonical structures
Working with well known models in we discuss the physics behind the
deformation of the canonical structure of these theories. A new deformation is
constructed linking the massless scalar field theory with the self-dual theory.
This is the exact dual of the known deformation connecting the Maxwell theory
with the Maxwell-Chern-Simons theory. Duality is used to establish a web of
relations between the mentioned theories and a physical picture of the
deformation procedure is suggested.Comment: revtex4 file, 16 page
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