118388669
Lovelock-Lifshitz black holes
In this paper, we investigate the existence of Lifshitz solutions in Lovelock gravity, both in vacuum and in the presence of a massive vector field. We show that the Lovelock terms can support the Lifshitz solution provided the constants of the theory are suitably chosen. We obtain an exact black hole solution with Lifshitz asymptotics of any scaling parameter z in both Gauss-Bonnet and in pure 3rd order Lovelock gravity. If matter is added in the form of a massive vector field, we also show that Lifshitz solutions in Lovelock gravity exist; these can be regarded as corrections to Einstein gravity coupled to this form of matter. For this form of matter we numerically obtain a broad range of charged black hole solutions with Lifshitz asymptotics, for either sign of the cosmological constant. We find that these asymptotic Lifshitz solutions are more sensitive to corrections induced by Lovelock gravity than are their asymptotic AdS counterparts. We also consider the thermodynamics of the black hole solutions and show that the temperature of large black holes with curved horizons is proportional to r0z where z is the critical exponent; this relationship holds for black branes of any size. As is the case for asymptotic AdS black holes, we find that an extreme black hole exists only for the case of horizons with negative curvature. We also find that these Lovelock-Lifshitz black holes have no unstable phase, in contrast to the Lovelock-AdS case. We also present a class of rotating Lovelock-Lifshitz black holes with Ricci-flat horizons.
119193740
Surface terms of quasitopological gravity and thermodynamics of charged rotating black branes
We introduce the surface term for quasitopological gravity in order to make the variational principle of the action well defined. We also introduce the charged black branes of quasitopological gravity and calculate the finite action through the use of the counterterm method. Then we compute the thermodynamic quantities of the black brane solution by use of Gibbs free energy and investigate the first law of thermodynamics by introducing a Smarr-type formula. Finally, we generalize our solutions to the case of rotating charged solutions.
120841424
EVALUATION OF THE GRAVITON TWO-POINT FUNCTION IN DE SITTER SPACE
After a brief review of the linearized gravity in de Sitter (dS) four-dimensional space and ambient flat five-dimensional notations, the linearized field equation is written in terms of the Casimir operators of dS group. It is shown that the field equation is gauge invariant under some special gauge transformations. Because of this gauge freedom, a gauge-fixing parameter c is inserted in the field equation. It is shown that the solution to the field equation can be written as the multiplication of a generalized symmetric rank-2 polarization tensor and a massless minimally coupled scalar field in ambient space notations. The graviton two-point function has been thoroughly calculated, which is dS-invariant and free of any divergences. This two-point function has been expressed in terms of the intrinsic dS coordinates, from its ambient space counterpart, which is clearly dS-invariant and free of any divergences again.
123162229
Generalized uncertainty principle, modified dispersion relation and Reissner–Nordström black hole tunneling radiation
Abstract The Parikh–Kraus–Wilczek tunneling proposal of black hole tunneling radiation is considered. Reissner–Nordstrom black hole thermodynamics is studied according to the generalized uncertainty principle and the modified dispersion relation analysis. It is shown that entropy, temperature and the original Parikh–Kraus–Wilczek calculation of the black hole tunneling probability receive new corrections. The results of these two alternative approaches are identical if one uses the suitable expansion coefficients.
120170973
Tunneling black hole radiation, generalized uncertainty principle and de Sitter–Schwarzschild black hole
Abstract The Parikh–Wilczek tunneling proposal of black hole radiation is considered in de Sitter–Schwarzschild space–time. The semi-classical black hole tunneling radiation is calculated under a minimal length uncertainty analysis. It is shown that the original calculation of Parikh–Wilczek receives a new correction.
199678500
Violation of no hair conjecture in Einstein-Maxwell-Higgs system
7428020
The reduced phase space of an open string in the background B-field
The problem of an open string in background B-field is discussed. Using the discretized model in details we show that the system is influenced by an infinite number of second class constraints. We interpret the allowed Fourier modes as the coordinates of the reduced phase space. This enables us to compute the Dirac brackets more easily. We prove that the coordinates of the string are non-commutative at the boundaries. We argue that in order to find the Dirac bracket or commutator algebra of the physical variables, one should not expand the fields in terms of the solutions of the equations of motion. Instead, one should impose a set of constraints in suitable coordinates.
118016384
Constraint structure and Hamiltonian treatment of Nappi-Witten model
We investigate the Hamiltonian analysis of Nappi-Witten model (WZW action based on non semi simple gauge group) and find a time dependent non-commutativity by canonical quantization. Our procedure is based on constraint analysis of the model in two parts. A first class analysis is used for gauge fixing the original model following by a second class analysis in which the boundary condition are treated as Dirac constraints. We find the reduced phase space by imposing our second class constraints on the variables in an extended Fourier space.
1539587
Noncommutative Geometry and Classical Orbits of Particles in a Central Force Potential
We investigate the effect of the noncommutative geometry on the classical orbits of particles in a central force potential The relation is implemented through the modified commutation relations [xi,xj] = iθij. Comparison with observations places severe constraints on the value of the noncommutativity parameter.