Fermionic $\theta$ Vacua and Long-Necked Remnants
Abstract
We study a vacuum polarization effect in the background of certain dilatonic extremal black hole, known as the cornucopion. Whenever the charged fermions are of any finite mass, the gravitational backreaction to a generic value of a nonconserving vacuum angle is shown to be important owing to a vacuum energy density which does not vanish deep inside the cornucopion. When this energy density is positive, this effect creates an extremal horizon at finite physical distance, closing off the infinite neck. We study the geometry near this horizon in some detail and find different physical interpretations for small and large fermion mass. Also, we argue that the conclusion is qualitatively correct despite the strong coupling.
Cite
@article{arxiv.hep-th/9312021,
title = {Fermionic $\theta$ Vacua and Long-Necked Remnants},
author = {Piljin Yi},
journal= {arXiv preprint arXiv:hep-th/9312021},
year = {2010}
}
Comments
LaTeX, 17 pages, one uuencoded figure, CALT-68-1904, {Some editorial changes as suggested by an anonymous referee, one figure added, to appear in Phys. Rev. D Rapid Comm.}