Physics – High Energy Physics – High Energy Physics - Theory
Scientific paper
1998-10-12
Class.Quant.Grav.15:L89-L98,1998
Physics
High Energy Physics
High Energy Physics - Theory
11 pages, plain TeX, no figures. Accepted for publication as a "Letter to the Editor" in "Classical and Quantum Gravity"
Scientific paper
10.1088/0264-9381/15/12/003
A theory recently proposed by the author aims to explain decoherence and the thermodynamical behaviour of closed systems within a conservative, unitary, framework for quantum gravity by assuming that the operators tied to the gravitational degrees of freedom are unobservable and equating physical entropy with matter-gravity entanglement entropy. Here we obtain preliminary results on the extent of decoherence this theory predicts. We treat first a static state which, if one were to ignore quantum gravitational effects, would be a quantum superposition of two spatially displaced states of a single classically well describable ball of uniform mass density in empty space. Estimating the quantum gravitational effects on this system within a simple Newtonian approximation, we obtain formulae which predict e.g. that as long as the mass of the ball is considerably larger than the Planck mass, such a would-be-coherent static superposition will actually be decohered whenever the separation of the centres of mass of the two ball-states excedes a small fraction (which decreases as the mass of the ball increases) of the ball radius. We then obtain a formula for the quantum gravitational correction to the would-be-pure density matrix of a non-relativistic many-body Schroedinger wave function and argue that this formula predicts decoherence between configurations which differ (at least) in the "relocation" of a cluster of particles of Planck mass. We estimate the entropy of some simple model closed systems, finding a tendency for it to increase with "matter-clumping" suggestive of a link with existing phenomenological discussions of cosmological entropy increase.
No associations
LandOfFree
Decoherence of Macroscopic Closed Systems within Newtonian Quantum Gravity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Decoherence of Macroscopic Closed Systems within Newtonian Quantum Gravity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Decoherence of Macroscopic Closed Systems within Newtonian Quantum Gravity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-619531