Entanglement decoherence in a gravitational well according to the event formalism

Abstract

The event formalism is a nonlinear extension of quantum field theory designed to be compatible with the closed time-like curves that appear in general relativity. Whilst reducing to standard quantum field theory in flat space-time the formalism leads to testably different predictions for entanglement distribution in curved space. In this paper we introduce a more general version of the formalism and use it to analyse the practicality of an experimental test of its predictions in the Earthʼs gravitational well.

Quantum measurements of signals from the Alphasat TDP1 laser communication terminal

“…In order to optimize the system for quantum communication, our next step is the adaptation of the sender and receiver for applied QKD. Furthermore, on the fundamental research side, the large gravitational potential difference between GEO and ground allows to investigate gravitational effects on quantum states [56][57][58][59][60].…”

Space QUEST mission proposal: experimentally testing decoherence due to gravity

“…Thus, it is possible, in principle, to recover the information that has been lost by adjusting the detector to correct the gravitationally induced effects. In contrast, the model proposed in [4,5] predicts an irrecoverable gravitational decoherence effect due to a speculative nonlinear back-action of the metric on the quantum fields that leads to particle loss into a causally disconnected region of space-time. Furthermore, [4][5][6][7][8][9][10][11] show that this type of decoherence effect is seen only by entangled systems (i.e., classical correlations are not affected).…”

“…The primary consequence of this curvature-induced nonlinearity is a loss of quantum entanglement over and beyond what would be expected from known sources of environmental decoherence. The physical reason for this decoherence is explained in [4,5].…”

“…Uniquely, the predictions of [4,5], referred to as the event operator formalism, can be experimentally verified with current technology, providing a rare opportunity to test models of fundamental QM and general relativity (GR) simultaneously. The event operator formalism represents a particular class of theories that attempts to combine quantum and relativistic effects in a consistent way.…”

Focus on gravitational quantum physics

“…This should be contrasted with quantum-field theory combined with gravity by Anastopoulos and Hu, who show that the Schrödinger-Newton equation appears as a mean-field limit effective theory, but on the fundamental level the theory remains linear [10]. Another nonlinear extension of quantum theory designed to be compatible with the occurrence of closed time-like curves in space-times that may appear as solutions to the field equations of general relativity is discussed by Ralph and Pienaar [11].…”