Towards Matter-Wave Interferometry with Optically Levitated Nanospheres*

Demonstration of matter-wave interference with optically levitated nanospheres has the potential

to extend the current limit on matter-wave interference by three to four orders of magnitude.

This would provide pathways towards the realization of gravity-induced entanglement experiments

as well as tests of decoherence and wave function collapse models. Towards this end, I report

progress on the construction of a cryogenic and extremely high vacuum (EHV) experiment suitable

for laser-cooling and optical levitation of dielectric nanospheres. To preserve a coherence time

of approximately 200ms, experimental challenges such as near motional ground state cooling,

pressures below 10-13mbar, internal temperatures below 100K, and relative position stability on

the order of tens of nanometers must be overcome. This apparatus additionally allows for precision

measurements of short-range forces to test Newtonian gravity at sub-micron scales, the Casimir-

Polder force, matter neutrality, and other fundamental forces.