Regular Article

Quantum sensing with milligram scale optomechanical systems^★

¹ Department of Physics, University of Tokyo Bunkyo, Tokyo 113-0033, Japan
² LIGO Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

^a e-mail: michimura@granite.phys.s.u-tokyo.ac.jp
^b e-mail: kentarok@mit.edu

Received: 31 March 2020
Received in final form: 28 April 2020
Published online: 18 June 2020

Abstract

Probing the boundary between classical and quantum mechanics has been one of the central themes in modern physics. Recently, experiments to precisely measure the force acting on milligram scale oscillators with optical cavities are attracting interest as promising tools to test quantum mechanics, decoherence mechanisms, and gravitational physics. In this paper, we review the present status of experiments using milligram scale optomechanical systems. We compare the feasibility of reaching the quantum regime with a pendulum, torsion pendulum, and optically levitated mirror. Considerations for designing a high Q pendulum, condition for torsion pendulums to have better force sensitivity than pendulums, and constraints in designing optical levitation of a mirror are presented.