Recent progress and perspectives of extremely low loss acoustic cavities: From frequency sources to artificial atoms

Bulk Acoustic Wave devices with effective phonon trapping demonstrate extremely low losses superior to any other mechanical systems currently under investigations. It is demonstrated that quality factors of such systems approach the level of 10¹⁰ at relatively high frequencies approaching one GHz. The record high Q×f product of 1.6×10¹⁸ opens a wide range of applications for such devices including testing of fundamental physics, quantum hybrid systems and high precision frequency generation.