Photonic Implementation of Quantum Gravity Simulator

TL;DR

This paper demonstrates a photonic simulation of gravity-mediated entanglement, providing insights into quantum gravity phenomena through experimental and theoretical analysis using various entanglement detection methods.

Contribution

It introduces a photonic platform to simulate gravity-mediated entanglement and compares different testing methods, advancing understanding of quantum gravity interactions.

Findings

Bell test confirms gravity-mediated nonlocality

Quantum state tomography certifies presence or absence of entanglement

Simulation reveals importance of encoding and erasing which-path information

Abstract

Detecting gravity mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics. We report the result of a simulation of the phenomenon using a photonic platform. The simulation tests the idea of probing the quantum nature of a variable by using it to mediate entanglement, and yields theoretical and experimental insights. We employed three methods to test the presence of entanglement: Bell test, entanglement witness and quantum state tomography. We also simulate the alternative scenario predicted by gravitational collapse models or due to imperfections in the experimental setup and use quantum state tomography to certify the absence of entanglement. Two main lessons arise from the simulation: 1) which--path information must be first encoded and subsequently coherently erased from the gravitational field, 2) performing a Bell test leads to stronger conclusions, certifying the existence of gravity mediated nonlocality.