Room-Temperature Mechanical Resonator with a Single Added or Subtracted Phonon

Area of Science:

• Quantum physics
• Cavity optomechanics
• Condensed matter physics

Background:

• Mechanical oscillators at room temperature exhibit thermal Brownian motion.
• Controlling quantum states of macroscopic mechanical systems is a significant challenge.
• Cavity optomechanics offers a pathway to couple light and mechanical motion.

Purpose of the Study:

• To demonstrate the addition and subtraction of single phonons in a room-temperature mechanical oscillator.
• To characterize the quantum state of the mechanical oscillator after phonon manipulation.
• To explore non-Gaussian mechanical states using quantum measurement techniques.

Main Methods:

• Utilized a cavity-optomechanical setup to interact a mechanical oscillator with laser light.
• Performed strong quantum measurement by counting photons in sidebands to herald phonon events.
• Implemented a quantum tomography scheme and maximum likelihood estimation to infer the mechanical state.

Main Results:

• Successfully heralded the addition and subtraction of single phonons on a 4 GHz mechanical oscillator at 300 K.
• Observed highly non-Gaussian phase-space distributions, indicating non-classical mechanical states.
• Confirmed a counterintuitive doubling of the mean phonon number following phonon addition and subtraction.

Conclusions:

• Precise quantum control over macroscopic mechanical oscillators at room temperature is achievable.
• Cavity optomechanics enables the generation and characterization of non-Gaussian mechanical states.
• The demonstrated phonon manipulation opens avenues for quantum information processing with mechanical systems.