AQP Seminar: Quantum electromechanics: from nonreciprocity to entanglement

Aalto Quantum Physics Seminar (Nanotalo). Speaker: Dr. Shabir Barzanjeh (IST, Austria)

Mechanical quantum systems facilitate the development of a new generation of hybrid quantum technology comprising electrical, optical, atomic and acoustic degrees of freedom. Entanglement is the essential resource that defines this new paradigm of quantum-enabled devices.  Here I confirm the long-standing prediction that a parametrically driven mechanical oscillator can entangle electromagnetic fields. We observe stationary emission of path-entangled microwave radiation from a micro-machined silicon nanostring oscillator, squeezing the joint field operators of two thermal modes by 3.40(37)~dB below the vacuum level. Interestingly, even at room temperature, where entangled microwave states are overwhelmed by thermal and amplifier noises, we measure finite quantum correlations; a first indication that superconducting circuits could be used for quantum enhanced detection at ambient conditions. Nevertheless, we experimentally demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanic interactions. This mechanical based circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. This special circulator can also be used to control the flow of thermal noises and heat in quantum devices.