Quantum inequalities and their application
Abstract
A `quantum inequality' (a conjectured relation between the energy density of a free quantum field and the time during which this density is observed) has recently been used to rule out some of the macroscopic wormholes and warp drives. I discuss the possibility of generalizing that result to other similar spacetimes and first show that the problem amounts to verification of a slightly different inequality. This new inequality \emph{can} replace the original one, if an additional assumption (concerning homogeneity of the `exotic matter' distribution) is made, and \emph{must} replace it if the assumption is relaxed. Then by an explicit example I show that the `new' inequality breaks down even in a simplest case (a free field in a simply connected two dimensional space). Which suggests that there is no grounds today to consider such spacetimes `unphysical'.
 Publication:

Gravitation and Cosmology
 Pub Date:
 June 2006
 arXiv:
 arXiv:grqc/0409007
 Bibcode:
 2006GrCo...12..195K
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 Sec. II is completely rewritten: the gulf is discussed between the proven QIs and those used in ruling out exotic spacetimes