Passage of radiation through wormholes of arbitrary shape
Abstract
We study quasinormal modes and scattering properties via calculation of the S matrix for scalar and electromagnetic fields propagating in the background of spherically symmetric and axially symmetric traversable Lorentzian wormholes of a generic shape. Such wormholes are described by the general MorrisThorne ansatz. The properties of quasinormal ringing and scattering are shown to be determined by the behavior of the wormhole’s shape function b(r) and shift factor Φ(r) near the throat. In particular, wormholes with the shape function b(r), such that b^{'}(r)≈1, have very longlived quasinormal modes in the spectrum. We have proved that the axially symmetric traversable Lorentzian wormholes, unlike black holes and other compact rotating objects, do not allow for superradiance. As a byproduct we have shown that the 6th order WKB formula used for scattering problems of black or wormholes gives quite high accuracy and thus can be used for quite accurate calculations of the Hawking radiation processes around various black holes.
 Publication:

Physical Review D
 Pub Date:
 June 2010
 DOI:
 10.1103/PhysRevD.81.124036
 arXiv:
 arXiv:1004.1284
 Bibcode:
 2010PhRvD..81l4036K
 Keywords:

 04.30.Nk;
 04.70.Bw;
 Wave propagation and interactions;
 Classical black holes;
 High Energy Physics  Theory;
 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 10 pages, 11 figures, the automatic procedure for calculations of the 6th order WKB quasinormal modes and reflection/transmission coefficients can be found on https://goo.gl/nykYGL