Single-Photon Cooling in Microwave Magnetomechanics.

Area of Science:

• Quantum physics
• Cavity optomechanics
• Mesoscopic systems

Background:

• Cavity optomechanics enables control of mechanical motion near quantum limits.
• Achieving single-photon strong coupling is crucial for preparing non-Gaussian quantum states in massive resonators.
• Current microwave optomechanical systems face challenges with small optomechanical couplings for massive devices.

Purpose of the Study:

• To demonstrate a novel approach for achieving strong single-photon coupling in massive mechanical resonators.
• To explore the potential of magnetic coupling for enhancing optomechanical interactions.
• To advance the preparation of massive mechanical resonators in non-Gaussian quantum states for quantum mechanics testing.

Main Methods:

• Utilizing magnetic coupling between a mechanical resonator and a microwave cavity.
• Measuring single-photon coupling strength (g₀/2π) and single-photon cooperativity (C₀).
• Cooling the mechanical resonator using microwave photons.

Main Results:

• Demonstrated a single-photon coupling of g₀/2π∼3 kHz, an order of magnitude improvement over existing microwave optomechanical systems.
• Achieved a single-photon cooperativity C₀≳10, a significant step towards single-photon strong coupling.
• Cooled the massive mechanical resonator to one-third of its steady-state phonon population with fewer than two microwave photons.

Conclusions:

• The novel magnetic coupling approach significantly enhances optomechanical interactions for massive resonators.
• This method facilitates cooling massive mechanical resonators to low phonon numbers, crucial for quantum state preparation.
• The demonstrated strong coupling opens avenues for quantum foundation tests, quantum sensing, and microwave-to-optical transduction.