Gravity-mediated gain of quantum entanglement

Abstract

No experiment to date provided direct evidence for quantum features of gravitational interaction. Recently proposed tests suggest looking for generation of quantum entanglement between massive objects. Motivated by the success of cooling kilogram mirrors of the LIGO interferometer to near ground state, we study the entanglement dynamics between two massive objects interacting gravitationally. In this thesis, we will focus on two setups: 1) Entanglement of two optomechanical oscillators, 2) Entanglement of two free falling objects. We derive a figure of merit that characterises generated entanglement and entangling time, and show that squeezing of the initial state of the mirrors significantly improves the entanglement. The derivations are supplemented with numerical evidence showing accuracy of our approximations. All this provides a range of experimental parameters required for observation of the gravitationally-induced entanglement.