Test of some Fundamental Principles in Physics via Quantum Interference with Neutrons and Photons

TL;DR

This paper investigates how quantum interference with neutrons and photons can test fundamental principles of physics, highlighting experimental limitations, potential discrepancies, and the role of coherence effects in probing space-time structure.

Contribution

It introduces new insights into using neutron and photon interference experiments to test and challenge aspects of metric theories of gravity and space-time structure.

Findings

Neutron interference can confront measurement readouts with gravity principles.

Photon interference, especially Hanbury--Brown--Twiss effect, offers new experimental possibilities.

Semiclassical approximation imposes restrictions on studying space-time features.

Abstract

The limitations and possibilities that the concept of quantum interference offers as a tool for testing fundamental physics are explored here. The use of neutron interference as an instrument to confront against measurement readouts some of the principles behind metric theories of gravity will be analyzed, as well as some discrepancies between theory and experiment. The main restrictions that this model embodies for the study of some of the features of the structure of space--time will be explicitly pointed out. For instance, the conditions imposed by the necessary use of the semiclassical approximation. Additionally, the role that photon interference could play as an element in this context is also considered. In this realm we explore the differences between first-order and second-order coherence experiments, and underline the fact that the Hanbury--Brown--Twiss effect could open up some interesting experimental possibilities in the analysis of the structure of space--time. The void, in connection with the description of wave phenomena, implicit in the principles of metric theories is analyzed. The conceptual difficulties, that this void entails, are commented.