Cooling a macroscopic mechanical oscillator close to its quantum ground state

Recent advances in cavity quantum optomechanics have enabled breakthroughs such as ground state cooling of mechanical motion, observation of quantum backaction, standard quantum limit of position measurement and entanglement between optical and mechanical degrees of freedom [1]. Simultaneously, the upgraded version of current gravitational-wave interferometers is expected to suffer from optomechanical effects such as parametric instabilities and quantum backaction, while the sensitivity of such interferometers has already been quantum-enhanced [2]. Despite sharing the same fundamental optomechanical coupling mechanism, the typical mass of the mechanical degree of freedom in these two research fields differs by twelve orders of magnitude.