Electrical engineering

Quantum entanglement

Physics

Sideband

Optomechanics

Resonator

Optics

Engineering

Coupling (piping)

Physical chemistry

Artificial intelligence

Interferometry

Control (management)

Chemistry

Microwave

Computer science

Quantum mechanics

Control theory (sociology)

Positive feedback

Compatible sideband transmission

Mechanical engineering

Steady state (chemistry)

Quantum

Physical review. A/Physical review, A

We consider a wide family of optical coherent feedback loops acting on an optomechanical system operating in the linearized regime. We assess the efficacy of such loops in improving key operations, such as cooling, steady-state squeezing and entanglement, as well as optical-to-mechanical state transfer. We find that mechanical sideband cooling can be enhanced through passive, interferometric coherent feedback, achieving lower steady-state occupancies and considerably speeding up the cooling process; we also quantify the detrimental effect of nonzero delay times on the cooling performance. Steady-state entanglement generation in the blue sideband can also be assisted by passive interferometric feedback, which allows one to stabilize otherwise unstable systems, though active feedback (including squeezing elements) does not help to this aim. We show that active feedback loops only allow for the generation of optical, but not mechanical, squeezing. Finally, we prove that passive feedback can assist state transfer at transient times for red-sideband-driven systems in the strong-coupling regime.

Cavity optomechanics assisted by optical coherent feedback