Anomalies, effective action and Hawking temperatures of a Schwarzschild black hole in the isotropic coordinates

Motivated by the universality of Hawking radiation and that of the anomaly cancellation technique as well as that of the effective action method, we investigate the Hawking radiation of a Schwarzschild black hole in the isotropic coordinates via the cancellation of gravitational anomaly. After performing a dimensional reduction from the four-dimensional isotropic Schwarzschild metric, we show that this reduction procedure will, in general, result in two classes of two-dimensional effective metrics: the conformal equivalent and the inequivalent ones. For the physically equivalent class, the two-dimensional effective metric displays such a distinct feature that the determinant is not equal to the unity ($sqrt{-g} eq 1$), but also vanishes at the horizon, the latter of which possibly invalidates the anomaly analysis there. ... This is an updated version to replace our e-print arXiv:0709.0044 [hep-th]. Abstract is too long to exceed the limit of 24 lines by arXiv.

Comment on Hawking Radiation and Covariant Anomalies

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.