Quantum interference in external gravitational fields beyond General Relativity

TL;DR

This paper explores quantum interference effects in external gravitational fields within alternative gravity theories, revealing how different models influence phase shifts and decoherence, thus offering a potential method to test and distinguish these theories from general relativity.

Contribution

It introduces a framework to analyze quantum interference in generalized quadratic gravity theories, highlighting their distinct effects on phase shifts and decoherence compared to general relativity.

Findings

Gravitational phase shift proportional to derivative of modified Newtonian potential

Relativistic gravity causes observable coherence loss in quantum interference

Decoherence rate varies significantly across different gravity models

Abstract

In this paper, we study the phenomenon of quantum interference in the presence of external gravitational fields described by alternative theories of gravity. We analyze both non-relativistic and relativistic effects induced by the underlying curved background on a superposed quantum system. In the non-relativistic regime, it is possible to come across a gravitational counterpart of the Bohm-Aharonov effect, which results in a phase shift proportional to the derivative of the modified Newtonian potential. On the other hand, beyond the Newtonian approximation, the relativistic nature of gravity plays a crucial r\^ole. Indeed, the existence of a gravitational time dilation between the two arms of the interferometer causes a loss of coherence that is in principle observable in quantum interference patterns. We work in the context of generalized quadratic theories of gravity to compare their physical predictions with the analogous outcomes in general relativity. In so doing, we show that the decoherence rate strongly depends on the gravitational model under investigation, which means that this approach turns out to be a promising test bench to probe and discriminate among all the extensions of Einstein's theory in future experiments.