Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userComments on Lorentz Transformations, Dressed Asymptotic States and Hawking Radiation
67
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We consider two applications of the factorization of infrared dynamics in QED and gravity. The first is a redefinition of the Lorentz transformations that makes them commute with supertranslations. The other is the process of particle creation near a black hole horizon. For the latter we show that the emission of soft particles factors out of the S-matrix in the fixed-background approximation and to leading order in the soft limit. The factorization is implemented by dressing the incoming and outgoing asymptotic states with clouds of soft photons and soft gravitons. We find that while the soft photon cloud has no effect, the soft graviton cloud induces a phase shift in the Bogolyubov coefficients relating the incoming and outgoing modes. However, the flux of outgoing particles, given by the absolute value of the Bogolyubov coefficient, is insensitive to this phase.
rate research
Read More
The basic characteristics of the covariant chiral current $<J_{mu}>$ and the covariant chiral energy-momentum tensor $<T_{mu u}>$ are obtained from a chiral effective action. These results are used to justify the covariant boundary condition used in recent approaches cite{Isowilczek,Isoumtwilczek,shailesh,shailesh2,Banerjee} of computing the Hawking flux from chiral gauge and gravitational anomalies. We also discuss a connection of our results with the conventional calculation of nonchiral currents and stress tensors in different (Unruh, Hartle-Hawking and Boulware) states.
We comment on the consistence of the epsilon anti-symmetric tensor adopted in [R. Banerjee and S. Kulkarni, arXiv:0707.2449] when it is generalized in the general case where $sqrt{-g} eq 1$. It is pointed out that the correct non-minimal consistent gauge and gravitational anomalies should by multiplied a factor $sqrt{-g} eq 1$. We also sketch the generalization of their work to the $sqrt{-g} eq 1$ case.
Asymptotic single-particle states in quantum field theories with small departures from Lorentz symmetry are investigated perturbatively with focus on potential phenomenological ramifications. To this end, one-loop radiative corrections for a sample Lorentz-violating Lagrangian contained in the Standard-Model Extension (SME) are studied at linear order in Lorentz breakdown. It is found that the spinor kinetic operator, and thus the free-particle physics, is modified by Lorentz-violating operators absent from the original Lagrangian. As a consequence of this result, both the standard renormalization procedure as well as the Lehmann-Symanzik-Zimmermann reduction formalism need to be adapted. The necessary adaptations are worked out explicitly at first order in Lorentz-breaking coefficients.
Hawking radiation is obtained from the Reissner-Nordstr{o}m blackhole with a global monopole and the Garfinkle-Horowitz-Strominger blackhole falling in the class of the most general spherically symmetric blackholes $(sqrt{-g} eq1)$, using only chiral anomaly near the event horizon and covariant boundary condition at the event horizon. The approach differs from the anomaly cancellation approach since apart from the covariant boundary condition, the chiral anomaly near the horizon is the only input to derive the Hawking flux.
Hawking radiation is obtained from anomalies resulting from a breaking of diffeomorphism symmetry near the event horizon of a black hole. Such anomalies, manifested as a nonconservation of the energy momentum tensor, occur in two different forms -- covariant and consistent. The crucial role of covariant anomalies near the horizon is revealed since this is the {it only} input required to obtain the Hawking flux, thereby highlighting the universality of this effect. A brief description to apply this method to obtain thermodynamic entities like entropy or temperature is provided.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
