Quantum control of surface acoustic-wave phonons.

Area of Science:

• Quantum Physics
• Quantum Mechanics
• Cavity Optomechanics

Background:

• Non-classical quantum states and superpositions are hallmarks of quantum physics, demonstrated in systems like ions and photons.
• Previous demonstrations in mechanical systems were indirect, limited by linear responses and low frequencies hindering quantum ground state access.
• Mechanical systems offer potential in quantum sensing, computation, and communication.

Purpose of the Study:

• To demonstrate full quantum control over the mechanical state of a macroscale mechanical resonator.
• To generate and precisely manipulate non-classical quantum states in a mechanical system.
• To enable applications of mechanical resonators in the quantum regime.

Main Methods:

• Strongly coupling a surface acoustic-wave (SAW) resonator to a superconducting qubit.
• Utilizing the superconducting qubit for control and measurement of quantum states in the mechanical resonator.
• Employing Wigner tomography for state mapping and characterization.

Main Results:

• Achieved full quantum control of the mechanical state of a macroscale resonator.
• Generated a non-classical superposition of zero- and one-phonon Fock states.
• Successfully mapped quantum states using Wigner tomography.

Conclusions:

• Demonstrated precise, programmable quantum control of a macroscale mechanical resonator.
• This capability is crucial for advancing surface acoustic wave applications in the quantum limit.
• Opens possibilities for coupling disparate quantum systems and developing novel quantum technologies.