Quantum Fluctuation Phenomena in Macroscopic Quantum Systems: Exploring the Foundations of Quantum Mechanics with Levitated Nanospheres

Fluctuation forces such as the Casimir or van der Waals force have been extensively studied for systems with a localized center-of-mass. To this date it is an open question how these descriptions of fluctuation effects extend to the quantum regime where systems can be in spatial superposition. Since systems of two optically trapped nanospheres, which can be cooled down to their ground state, have now been realized in our lab, we propose to (1) analyze and control fluctuation-induced forces between nanospheres using external drives; (2) study the effect of center-of-mass correlations and entanglement between the nanospheres on the fluctuation-mediated interactions forces and decoherence induced by the fluctuating field; and (3) explore ways to experimentally realize macroscopic quantum superpositions of levitated nanospheres pertinent to ongoing experiments. By the end of this project we aim to have a description of a wide range of interactions allowing us to tailor interparticle potentials. We will also have gained insights into the nature of superpositions of macroscopic systems and their decoherence induced by fluctuating fields. This will pave the way for future explorations of gravitational effects in quantum systems.