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Robert McNees

Publications and source records attributed to Robert McNees.

24 records · Page 2Linked to original sources
arXiv2007

Thermodynamics of Black Holes in Two (and Higher) Dimensions

A comprehensive treatment of black hole thermodynamics in two-dimensional dilaton gravity is presented. We derive an improved action for these theories and construct the Euclidean path integral. An essentially unique boundary counterterm renders the improved action finite on-shell, and its variational properties guarantee that the path integral has a well-defined semi-classical limit. We give a detailed discussion of the canonical ensemble described by the Euclidean partition function, and examine various issues related to stability. Numerous examples are provided, including black hole backgrounds that appear in two dimensional solutions of string theory. We show that the Exact String Black Hole is one of the rare cases that admits a consistent thermodynamics without the need for an external thermal reservoir. Our approach can also be applied to certain higher-dimensional black holes, such as Schwarzschild-AdS, Reissner-Nordstrom, and BTZ.

hep-th↗
arXiv2005

A New Boundary Counterterm for Asymptotically AdS Spacetimes

We present a modified version of the boundary counterterm method for removing divergences from the action of an asymptotically $AdS$ spacetime. The standard approach renders the action finite but leaves diffeomorphism invariance partially broken if the dimension of the spacetime is odd. We show that this symmetry is restored by a new boundary counterterm, needed to cancel a divergence that appears in dimensional regularization. The result is a finite, diffeomorphism invariant action appropriate for gravitational physics. As an example we calculate the action for the Kerr-$AdS_5$ black hole. Unlike the standard boundary counterterm results, our action yields conserved charges that are consistent with the first law of black hole thermodynamics.

hep-th↗
arXiv2005

Boundary Counterterms and the Thermodynamics of 2-D Black Holes

We utilize a novel method to study the thermodynamics of two dimensional type 0A black holes with constant RR flux. Our approach is based on the Hamilton-Jacobi method of deriving boundary counterterms. We demonstrate this approach by recovering the standard results for a well understood example, Witten's black hole. Between this example and the 0A black hole we find universal expressions for the entropy and black hole mass, as well as the infra-red divergence of the partition function. As a non-trivial check of our results we verify the first law of thermodynamics for these systems. Our results for the mass disagree with the predictions of a proposed matrix model dual of the 0A black hole.

hep-th↗
arXiv2004

Holography, Diffeomorphisms, and Scaling Violations in the CMB

We analyze diffeomorphism invariance in inflationary spacetimes regulated by a boundary at late time. We present the action for quadratic fluctuations in the presence of a boundary, and verify that it is gauge invariant precisely when the correct local counterterms are included. The scaling behavior of bulk correlation functions at the boundary is determined by Callan-Symanzik equations which predict scaling violations in agreement with the standard inflationary predictions for spectral indices of the CMB.

hep-th↗
arXiv2003

Inflation and de Sitter Holography

We develop the relation between de Sitter holography and inflation in detail, with particular attention to cosmic density perturbations. We set up the Hamilton-Jacobi formalism to present a systematic treatment of the logarithmic corrections to a scale invariant spectrum. Our computations can be interpreted without reference to holography, as strong infra-red effects in gravity. This point of view may be relevant for the fine-tuning problems inherent to inflation.

hep-th↗