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 SU(2)qSU(2)_{q} 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