Ground State Cooling of an Ultracoherent Electromechanical System

Understand

Cavity electromechanics relies on parametric coupling between microwave and mechanical modes to manipulate the mechanical quantum state, and provide a coherent interface between different parts of hybrid quantum systems.

• High coherence of the mechanical mode is of key importance in such applications, in order to protect the quantum states it hosts from thermal decoherence.
• Here, we introduce an electromechanical system based around a soft-clamped mechanical resonator with an extremely high Q-factor (>$10^9$) held at very low (30 mK) temperatures.
• This ultracoherent mechanical resonator is capacitively coupled to a microwave mode, strong enough to enable ground-state-cooling of the mechanics ($\bar{n}_\mathrm{min}= 0.76\pm 0.16$).