Fermion scattering off dilatonic black holes

Abstract

The scattering of massless fermions off magnetically charged dilatonic black holes is reconsidered and a violation of unitarity is found. Even for a single species of fermion it is possible for a particle to disappear into the black hole with its information content.In recent years there has been a lot of interest in the physics of black holes. The issue which has engaged the attention of most workers is that of possible information loss. Matter falling into a black hole carries some information with it. This becomes inaccessible to the rest of the world, but may in principle be supposed to be stored inside the black hole in some sense. A problem arises when the black hole evaporates through the process of Hawking radiation. The information does seem to be lost now [1].Although there have been attempts at studying this problem in its full complexity [2], most authors have considered simplified models of black holes as in [3,4]; see [5] for a review. We shall consider the extremal magnetically charged black hole solution of dilatonic gravity. This is a four dimensional model involving an extra field -the dilaton -but for s-wave scattering of particles in the field of this black hole, the angular coordinates are not relevant and a two dimensional 1 e-mail mitra@saha.ernet.in 1

Does Chiral Fermion Coupled to a Background Dilaton Field Preserve Information?

“…Thus in the description of scattering of chiral fermion where U(1) anomaly has been taken into account with the introduction of Faddeevian class of anomalous term is found to be free from the dangerous information loss problem. Note that this result is just opposite to the conclusion of [11]. The analysis available in [11] and the present analysis differs only in the anomaly structure but this particular class of anomaly has brought a novel change in the information scenario for chiral fermion.…”

“…Note that this result is just opposite to the conclusion of [11]. The analysis available in [11] and the present analysis differs only in the anomaly structure but this particular class of anomaly has brought a novel change in the information scenario for chiral fermion. It is tempting to note that the change appeared in the scattering of chiral fermion in connection with information scenario is consistent with the standard belief as well as with the Hawking's recent suggestion.…”

“…Angular momentum coordinate becomes irrelevant in this situation and a two dimensional effective action results. Though those simplified models do not capture the detailed physics of black hole those models contain the information loss paradox in a significant way [8,10,11]. Scattering of fermion was not studied only in connection with information loss, scattering of boson was also studied in [12,13,14] in the same context.…”

“…[11], the authors showed that the scattering of chiral fermion can be studied in presence of the anomalies too if one deals with the bosonized lagrangian. The process of bosonization forces anomaly to enter into the picture.…”

“…The scattering of chiral fermion off dilaton black hole was not ignored too. It was considered with a particular interest in [11].…”