Lasers could shine light on quantum gravity

23 August 2012 Physics involving quantum mechanics and gravity need not involve the rather inaccessible Planck scale of 1019 GeV. A new proposal by Gianluca Gregori of the University of Oxford and colleagues suggests using lasers to provide large accelerations…

23 August 2012

Physics involving quantum mechanics and gravity need not involve the rather inaccessible Planck scale of 1019 GeV. A new proposal by Gianluca Gregori of the University of Oxford and colleagues suggests using lasers to provide large accelerations that would mimic (via the equivalence principle) the effect of gravity on electrons.

A high-energy (100 J) laser would strike a gas jet, creating a channel of plasma about 0.2 mm long in which electrons would be accelerated by a second laser, in this case a high-intensity (1019 W/cm2) pulsed optical laser. Thomson scattering of X-rays from a third laser – a free-electron laser providing 0.5 keV photons – would reveal via broadening the presence of an effectively non-Minkowski metric.

The requisite lasers are not yet available all in one place. Suggestions for a facility of this kind have already been made at both the Linac Coherent Light Source at Stanford and at the European XFEL at DESY. A laboratory test of quantum mechanics in non-Minkowski space–time might not be far off – with no black holes needed!