37 research outputs found
Rotating black hole in extended Chern-Simons modified gravity
We investigate a slowly rotating black hole in four-dimensional extended
Chern-Simons modified gravity. We obtain an approximate solution that reduces
to the Kerr solution when a coupling constant vanishes. The Chern-Simons
correction effectively reduces the frame-dragging effect around a black hole in
comparison with that of the Kerr solution.Comment: 9 pages, 1 figure, to appear in Progress of Theoretical Physics,
typos correcte
Does a black hole rotate in Chern-Simons modified gravity?
Rotating black hole solutions in the (3+1)-dimensional Chern-Simons modified
gravity theory are discussed by taking account of perturbation around the
Schwarzschild solution. The zenith-angle dependence of a metric function
related to the frame-dragging effect is determined from a constraint equation
independently of a choice of the embedding coordinate. We find that at least
within the framework of the first-order perturbation method, the black hole
cannot rotate for finite black hole mass if the embedding coordinate is taken
to be a timelike vector. However, the rotation can be permitted in the limit of
(where is the black hole mass and is the radius). For a
spacelike vector, the rotation can also be permitted for any value of the black
hole mass.Comment: 4 pages, Accepted for publication in Phys. Rev.
Conical Singular Solutions in (2+1)-Dimensional Gravity Employing the ADM Canonical Formalism
Topological solutions in the (2+1)-dimensional Einstein theory of gravity are
studied within the ADM canonical formalism. It is found that a conical
singularity appears in the closed de Sitter universe solution as a topological
defect in the case of the Einstein theory with a cosmological constant. Quantum
effects on the conical singularity are studied using the de Broglie-Bohm
interpretation. Finite quantum tunneling effects are obtained for the closed de
Sitter universe, while no quantum effects are obtained for an open universe.Comment: 15 pages, 3 figure
Discovery of parity-violating Majorana fermions in a chiral superconductor Sr2RuO4
We found parity-violating Majorana fermions in a chiral superconductor
Sr2RuO4. The current-voltage curves show an anomalous behavior: The induced
voltage is an even function of the bias current. The magnetic field dependent
results suggest the excitation of the Majorana fermions along the closed chiral
edge current of the single domain under bias current. We also discuss the
relationship between a change of the chirality and spontaneous magnetization of
the single domain Sr2RuO4
The Nakano-Nishijima-Gell-Mann Formula From Discrete Galois Fields
The well known Nakano-Nishijima-Gell-Mann (NNG) formula relates certain
quantum numbers of elementary particles to their charge number. This equation,
which phenomenologically introduces the quantum numbers (isospin),
(strangeness), etc., is constructed using group theory with real numbers
. But, using a discrete Galois field instead of
and assuring the fundamental invariance laws such as unitarity,
Lorentz invariance, and gauge invariance, we derive the NNG formula deductively
from Meson (two quarks) and Baryon (three quarks) representations in a unified
way. Moreover, we show that quark confinement ascribes to the inevitable
fractionality caused by coprimeness between half-integer (1/2) of isospin and
number of composite particles (e.g. three).Comment: 14 pages, 4 figures, 2 table
Binding Energy of Scalar Bound State by Topologically Massive Interaction: Fermion and Anti-fermion System with Heavy Mass
A bound state problem in a topologically massive quantum electrodynamics is
investigated by using a non-perturbative method. We formulate the Bethe-
Salpeter equation for scalar bound states composed of massive fermion and
anti-fermion pair under the lowest ladder approximation. In a large mass
expansion for the (anti-) fermion, we derive the Schr{\"o}dinger equation and
solve it by a numerical method. The energy eigenvalues of bound states are
evaluated for various values of a topological mass and also a fermion mass.
Then we find a novel logarithmic scaling behaviour of the binding energy in
varying the topological mass, fermion mass and also a quantum number. There
exists a critical value of the topological mass, beyond which the bound states
disappear. As the topological mass decreases, the energy eigenvalues of the
bound states, which are negative, also decrease with a logarithmic dependence
on the topological mass. A Chern-Simons term gives the bound system a repulsive
effect.Comment: 14 pages, 3 figures, references added; version accepted for
publication in Phys. Lett.
Flat rotation curves in Chern-Simons modified gravity
We investigate the spacetime of a slowly rotating black hole in the
Chern-Simons modified gravity. The long range feature of frame-dragging effect
under the Chern-Simon gravity well explains the flat rotation curves of
galaxies which is a central evidence of dark matter. Our solution provides a
different scenario of rotating space from Goedel's solution.Comment: 4 pages, Accepted for publication in Phys. Rev.