Collective motion of ultracold atoms strongly coupled to an optical resonator

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The theory of quantum mechanics famously places restrictions on the amount of information we can ever gather about some physical system. One route for exploring the limits of quantum metrology is the measurement of motion of macroscopic mechanical oscillators, for example nanofabricated cantilevers or membranes of various types. While these systems have yet to reach quantum limits of sensitivity and state-preparation, they hold promise for addressing the intriguing question of whether quantum mechanics retains its validity for describing ever-larger objects. This project represents a novel approach to micro-mechanics and quantum measurement. In it the collective motion of a macroscopic ensemble of ultracold atoms takes the place of the nanofabricated mechanical resonator. The advantages of using this system are that the resonator can be cooled directly to its quantum-mechanical ground state and that the mechanisms for actuating and measuring the resonator are founded solidly on quantum optics. In this work, the PI and his students will investigate quantum limited measurements, classical and quantum aspects of bistable motion, and, ultimately, the effects of strong coupling between the quantum fluctuations of a mechanical object and a single-mode light field. This work will inform the development of quantum technologies of various types, including superconducting quantum-interference (SQUID) amplifiers and nanomechanical resonators, by giving clear guidelines for approaching quantum limited performance. Achieving quantum limits for detecting the motion of cold atoms is also directly applicable to cold-atom-based interferometric sensors that are being presently developed and deployed. Finally, in training graduate students at the intersection of quantum optics, atomic physics, and condensed-matter physics, the project will help to develop the quantum scientists and engineers who will realize the benefits of nascent quantum technologies.