PIRSA:16030112

Video URL

https://pirsa.org/16030112

Negative Energy and the Focussing of Light Rays

Wall, A. (2016). Negative Energy and the Focussing of Light Rays. Perimeter Institute for Theoretical Physics. https://pirsa.org/16030112

Wall, Aron. Negative Energy and the Focussing of Light Rays. Perimeter Institute for Theoretical Physics, Mar. 09, 2016, https://pirsa.org/16030112 

          @misc{ scivideos_PIRSA:16030112,
            doi = {10.48660/16030112},
            url = {https://pirsa.org/16030112},
            author = {Wall, Aron},
            keywords = {Other Physics},
            language = {en},
            title = {Negative Energy and the Focussing of Light Rays},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2016},
            month = {mar},
            note = {PIRSA:16030112 see, \url{https://scivideos.org/pirsa/16030112}}
          }

Aron Wall University of Cambridge

Talk numberPIRSA:16030112
DOI10.48660/16030112
Source RepositoryPIRSA
Collection
Talk Type Scientific Series
Subject

Abstract

In any quantum field theory, the energy flux at a point of spacetime can be negative.  This would produce a repulsive gravitational field causing nearby light rays to defocus.  This in turn threatens to produce a variety of exotic phenomena including traversable wormholes, warp drives, time machines, and evasion of singularity theorems.  I will describe a new "quantum focusing conjecture" that prevents such pathologies.  In the flat spacetime limit it reduces to a novel lower bound on the energy density, which can be proven for several classes of field theories.