Środowiskowe Seminarium z Informacji i Technologii Kwantowych

Quantum optomechanics allows cooling of mechanical harmonic oscillators close to their ground states, thus facilitating probing of quantum properties of macroscopic systems. We engineer a hybrid system consisting of such a mechanical resonator, a phononic crystal patterned SiN membrane, and a large Cesium spin ensemble coupled via light, to study entanglement of two distinct macroscopic systems. To optimally track the evolution of the hybrid system in the presence of highly non-white noise we develop an approach based on a quantum version of the Wiener filter, which is a Kalman filter operating for a time-stationary signal. Optimal tracking and entanglement entail applications in quantum-enhanced force sensing.