Superluminal travel requires negative energies
Abstract
I investigate the relationship between faster-than-light travel and weak-energy-condition violation, i.e., negative energy densities. In a general spacetime it is difficult to define faster-than-light travel, and I give an example of a metric which appears to allow superluminal travel, but in fact is just flat space. To avoid such difficulties, I propose a definition of superluminal travel which requires that the path to be traveled reach a destination surface at an earlier time than any neighboring path. With this definition (and assuming the generic condition) I prove that superluminal travel requires weak-energy-condition violation.
Keywords
Cite
@article{arxiv.gr-qc/9805003,
title = {Superluminal travel requires negative energies},
author = {Ken D. Olum},
journal= {arXiv preprint arXiv:gr-qc/9805003},
year = {2015}
}
Comments
5 pages, RevTeX, 2 figures with epsf. This paper now contains all the material of gr-qc/6805003 and gr-qc/9806091 since these became a single article in Phys. Rev. Lett