Theory of quantum gravitational decoherence

Stephen L. Adler, Angelo Bassi

Yuanxin Li

Martine Schut

Charis Anastopoulos, B. L. Hu

Gravitational decoherence (GD) refers to the effects of gravity in actuating the classical appearance of a quantum system. Because the underlying processes involve issues in general relativity (GR), quantum field theory (QFT), and quantum information, GD has fundamental theoretical significance. There is a great variety of GD models, many of them involving physics that diverge from GR and/or QFT. This overview has two specific goals along with one central theme: (i) present theories of GD based on GR and QFT and explore their experimental predictions; (ii) place other theories of GD under the scrutiny of GR and QFT, and point out their theoretical differences. We also describe how GD experiments in space in the coming decades can provide evidence at two levels: (a) discriminate alternative quantum theories and non-GR theories; (b) discern whether gravity is a fundamental or an effective theory.

Rodolfo Gambini, Rafael A. Porto, Jorge A. Pullin

Charis Anastopoulos, M. P. Blencowe, B. L. Hu

Among the many worthwhile quantum experiments taking advantage of long baselines in space, this white paper points to the far-reaching significance of gravitational decoherence experiments. These experiments can provide clues as to whether gravity is of a fundamental or an effective nature. They can also discriminate between the predictions of quantum field theory in curved spacetime, our default theory for quantum phenomena in background gravitational fields, and other popular alternative quantum theories.