4 research outputs found
Thermodynamics of phantom black holes in Einstein-Maxwell-Dilaton theory
A thermodynamic analysis of the black hole solutions coming from the
Einstein-Maxwell-Dilaton theory (EMD) in 4D is done. By consider the canonical
and grand-canonical ensemble, we apply standard method as well as a recent
method known as Geometrothermodynamics (GTD). We are particularly interested in
the characteristics of the so called phantom black hole solutions. We will
analyze the thermodynamics of these solutions, the points of phase transition
and their extremal limit. Also the thermodynamic stability is analyzed. We
obtain a mismatch of the between the results of the GTD method when compared
with the ones obtained by the specific heat, revealing a weakness of the
method, as well as possible limitations of its applicability to very
pathological thermodynamic systems. We also found that normal and phantom
solutions are locally and globally unstable, unless for certain values of the
coupled constant of the EMD action. We also shown that the
anti-Reissner-Nordstrom solution does not posses extremal limit nor phase
transition points, contrary to the Reissner-Nordstrom case.Comment: 23 pages, version accepted for publication in Physical Review
Complete loop quantization of a dimension 1+2 Lorentzian gravity theory
De Sitter Chern-Simons gravity in D = 1 + 2 spacetime is known to possess an
extension with a Barbero-Immirzi like parameter. We find a partial gauge fixing
which leaves a compact residual gauge group, namely SU(2). The compacticity of
the residual gauge group opens the way to the usual LQG quantization
techniques. We recall the exemple of the LQG quantization of SU(2) CS theory
with cylindrical space topology, which thus provides a complete LQG of a
Lorentzian gravity model in 3-dimensional space-time.Comment: Loops11 - Madrid - 2011 (4 pages, Latex
Quantization of Lorentzian 3d Gravity by Partial Gauge Fixing
D = 2+1 gravity with a cosmological constant has been shown by Bonzom and
Livine to present a Barbero-Immirzi like ambiguity depending on a parameter. We
make use of this fact to show that, for positive cosmological constant, the
Lorentzian theory can be partially gauge fixed and reduced to an SU(2)
Chern-Simons theory. We then review the already known quantization of the
latter in the framework of Loop Quantization for the case of space being
topogically a cylinder. We finally construct, in the same setting, a quantum
observable which, although non-trivial at the quantum level, corresponds to a
null classical quantity.Comment: Notation defect fixed on pages 5 (bottom) and 6 (around Eqs. 3.1)--
19 pages, Late