Quantum Control of Ultra-coherent Micro-Electro-Mechanical Systems

Objectif

Because of the intrinsic fragility of their quantum nature, mechanical systems occupy a unique position at the boundary between the quantum and classical worlds. Overcoming the long-standing challenge in observing such macroscopic quantum phenomena is not only of fundamental interest but also promises versatile applications, extending mechanical-oscillator technologies such as MEMS into the quantum regime. These systems could function as quantum memories, sensors, or transducers. The key milestone is to realize an ultra-coherent mechanical oscillator and coherently couple it to a strongly nonlinear quantum system, such as a superconducting qubit.

The Q-MEMS project will achieve this through a cross-disciplinary approach uniting materials science, microwave engineering, nanofabrication, and quantum physics. It will establish a new hybrid quantum platform that merges circuit optomechanics, which brings mechanical motion into the quantum regime, with circuit quantum electrodynamics (cQED), which provides strong quantum nonlinearity. Q-MEMS introduces a novel driving scheme that resolves the intrinsic conflict between these two architectures, allowing stable operation of cQED under strong microwave drives required for optomechanics, thereby enabling coherent coupling between a mechanical oscillator and a superconducting qubit. In parallel, Q-MEMS pioneers the use of epitaxial titanium nitride (TiN) membranes combined with dissipation-dilution engineering and flip-chip bonding techniques, targeting second-scale mechanical quantum coherence in a scalable architecture.

This breakthrough will mark a decisive step toward mechanical-oscillator-based quantum technologies. Ultimately, Q-MEMS will open a new experimental window to probe gravitationally induced decoherence or dark matter interactions, linking cutting-edge quantum engineering with the foundations of physics.