638 research outputs found
Quantum Kalb-Ramond Field in D-dimensional de Sitter Spacetimes
In this work we investigate the quantum theory of the Kalb-Ramond fields
propagating in dimensional de Sitter spacetimes using the dynamic invariant
method developed by Lewis and Riesenfeld [J. Math. Phys. 10, 1458 (1969)] to
obtain the solution of the time-dependent Schr\"odinger equation. The wave
function is written in terms of a number quantity satisfying of the
Milne-Pinney equation, whose solution can be expressed in terms of two
independent solutions of the respective equation of motion. We obtain the exact
solution for the quantum Kalb-Ramond field in the de Sitter background and
discuss its relation with the Cremmer-Scherk-Kalb-Ramond model
A note on black hole entropy, area spectrum, and evaporation
We argue that a process where a fuzzy space splits in two others can be used
to explain the origin of the black hole entropy, and why a "generalized second
law of thermodynamics" appears to hold in the presence of black holes. We reach
the Bekenstein-Hawking formula from the count of the microstates of a black
hole modeled by a fuzzy space. In this approach, a discrete area spectrum for
the black hole, which becomes increasingly spaced as the black hole approaches
the Planck scale, is obtained. We show that, as a consequence of this, the
black hole radiation becomes less and less entropic as the black hole
evaporates, in a way that some information about its initial state could be
recovered.Comment: 4 pages, 2 figure
Duality and fields redefinition in three dimensions
We analyze local fields redefinition and duality for gauge field theories in
three dimensions. We find that both Maxwell-Chern-Simons and the Self-Dual
models admits the same fields redefinition. Maxwell-Proca action and its dual
also share this property. We show explicitly that a gauge-fixing term has no
influence on duality and fields redefinition.Comment: 8 pages, suppressed contents. To appear in J. Phys.
Spinors Fields in Co-dimension One Braneworlds
In this work we analyze the zero mode localization and resonances of
spin fermions in co-dimension one Randall-Sundrum braneworld scenarios.
We consider delta-like, domain walls and deformed domain walls membranes.
Beyond the influence of the spacetime dimension we also consider three
types of couplings: (i) the standard Yukawa coupling with the scalar field and
parameter , (ii) a Yukawa-dilaton coupling with two parameters
and and (iii) a dilaton derivative coupling with parameter .
Together with the deformation parameter , we end up with five free parameter
to be considered. For the zero mode we find that the localization is dependent
of , because the spinorial representation changes when the bulk
dimensionality is odd or even and must be treated separately. For case (i) we
find that in odd dimensions only one chirality can be localized and for even
dimension a massless Dirac spinor is trapped over the brane. In the cases (ii)
and (iii) we find that for some values of the parameters, both chiralities can
be localized in odd dimensions and for even dimensions we obtain that the
massless Dirac spinor is trapped over the brane. We also calculated numerically
resonances for cases (ii) and (iii) by using the transfer matrix method. We
find that, for deformed defects, the increasing of induces a shift in the
peaks of resonances. For a given with domain walls, we find that the
resonances can show up by changing the spacetime dimensionality. For example,
the same case in do not induces resonances but when we consider
one peak of resonance is found. Therefore the introduction of more dimensions,
diversely from the bosonic case, can change drastically the zero mode and
resonances in fermion fields.Comment: 28 pages, 7 figure
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