119434187
Entropy for extremal Reissner-Nordstrom black holes
Abstract We find in the brick wall model that the entropy of scalar matter in an extremal Reissner-Nordstrom background does not vanish and in fact has a stronger divergence than usual. We also interpret earlier results on the classical action of these black holes to argue that the mass may be a measure of the gravitational entropy, somewhat like in string models.
120593680
Physical solution of chiral Schwinger model with new regularization
Abstract A recently proposed version of the chiral Schwinger model is solved in this paper. The exact fermion propagator is derived in a path integral approach. The operator equations of motion of the bosonised theory are solved. Finally, the operator solution of the fermionic form of the theory is constructed.
9159427
Poincaré invariance of anomalous gauge theories.
We establish the Poincare invariance of anomalous gauge theories in two dimensions, for both the Abelian and non-Abelian cases, in the canonical Hamiltonian formalism. It is shown that, despite the noncovariant appearance of the constraints of these theories, Poincare generators can be constructed which obey the correct algebra and yield the correct transformations in the constrained space.
7905729
Quantization of Gauge Theories with Anomalies
In this talk, we briefly review the basic concepts of anomalous gauge theories. It has been known for some time how theories with local anomalies can be handled. Recently it has been pointed out that global anomalies, which obstruct the quantization of certain gauge theories in the temporal gauge, get bypassed in canonical quantization.
17603490
Scalar field entropy in brane world black holes
A semiclassical calculation of entropy of a scalar field in the background of a class of brane world black holes (BWBH) is carried out in the presence of a brick wall cutoff when the 5D-bulk induced "tidal charge" has generic or extreme values.
119347706
Counting black hole microscopic states in loop quantum gravity
Counting of microscopic states of black holes is performed within the framework of loop quantum gravity. This is the first calculation of the pure horizon states using statistical methods, which reveals the possibility of additional states missed in the earlier calculations, leading to an increase of entropy. Also for the first time a microcanonical temperature is introduced within the framework.
42299755
BMS supertranslations and Weinberg’s soft graviton theorem
A bstractRecently it was conjectured that a certain infinite-dimensional “diagonal” subgroup of BMS supertranslations acting on past and future null infinity ( and ) is an exact symmetry of the quantum gravity S-matrix, and an associated Ward identity was derived. In this paper we show that this supertranslation Ward identity is precisely equivalent to Weinberg’s soft graviton theorem. Along the way we construct the canonical generators of supertranslations at , including the relevant soft graviton contributions. Boundary conditions at the past and future of and a correspondingly modified Dirac bracket are required. The soft gravitons enter as boundary modes and are manifestly the Goldstone bosons of spontaneously broken supertranslation invariance.
53655055
New symmetries of massless QED
A bstractAn infinite number of physically nontrivial symmetries are found for abelian gauge theories with massless charged particles. They are generated by large U(1) gauge transformations that asymptotically approach an arbitrary function εzz¯$$ \varepsilon \left(z,\overline{z}\right) $$ on the conformal sphere at future null infinity () but are independent of the retarded time. The value of ε at past null infinity () is determined from that on by the condition that it take the same value at either end of any light ray crossing Minkowski space. The ε ≠ constant symmetries are spontaneously broken in the usual vacuum. The associated Goldstone modes are zero-momentum photons and comprise a U(1) boson living on the conformal sphere. The Ward identity associated with this asymptotic symmetry is shown to be the abelian soft photon theorem.