222 research outputs found
Entropy of Killing horizons from Virasoro algebra in D-dimensional extended Gauss-Bonnet gravity
We treat D-dimensional black holes with Killing horizon for extended
Gauss-Bonnet gravity. We use Carlip method and impose boundary conditions on
horizon what enables us to identify Virasoro algebra and evaluate its central
charge and Hamiltonian eigenvalue. The Cardy formula allows then to calculate
the number of states and thus provides for microscopic interpretation of
entropy.Comment: 15 page
Reply to ``Comment on `Properties of the massive Thirring model from the XYZ spin chain' "
We elaborate in more details why lattice calculation in [Kolanovic et al,
Phys. Rev. D 62, 025021 (2000)] was done correctly and argue that incresing the
number of sites is not expected to change our conclusions on the mass spectrum.Comment: 2 pages, revtex 4, to be published in Phys. Rev.
Conformal entropy for generalised gravity theories as a consequence of horizon properties
We show that microscopic entropy formula based on Virasoro algebra follows
from properties of stationary Killing horizons for Lagrangians with arbitrary
dependence on Riemann tensor. The properties used are consequence of regularity
of invariants of Riemann tensor on the horizon. Eventual generalisation of
these results to Lagrangians with derivatives of Riemann tensor, as suggested
by an example treated in the paper, relies on assuming regularity of invariants
involving derivatives of Riemann tensor. This assumption however leads also to
new interesting restrictions on metric functions near horizon.Comment: 9 pages, appendix adde
Conformal entropy and stationary Killing horizons
Using Virasoro algebra approach, black hole entropy formula for a general class of higher curvature Lagrangians with arbitrary dependence on Riemann tensor can be obtained from properties of stationary Killing horizons. The properties used are a consequence of regularity of invariants of Riemann tensor on the horizon. As suggested by an example Lagrangian, eventual generalisation of these results to Lagrangians with derivatives of Riemann tensor, would require assuming regularity of invariants involving derivatives of Riemann tensor and that would lead to additional restrictions on metric functions near horizon
On Bethe strings in the two-particle sector of the closed invariant spin chain
In this paper we investigate complex solutions of the Bethe equations in the two-particle sector both for arbitrary finite number of sites and for the thermodynamic limit . We find the number of complex solutions (strings) and compare it with the string conjecture prediction. Some simple properties of these solutions like position in the spectrum, crossing of levels, connection to the ground state and transformation to the real solutions are discussed. Counting both real and complex solutions we find expected number of highest weight Bethe states
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