PhD Studentship: Quantum Information with Mechanical Systems (QuIMS): Modelling Nonlinear Quantum Optomechanical Devices

Quantum technologies require new approaches to overcoming limited coherence, control errors and connectivity between qubits. This 3.5-year PhD will investigate whether nanomechanical systems can provide an alternative platform for quantum information processing and quantum-enhanced sensing. The project focuses on suspended graphene resonators integrated with superconducting microwave cavities. Because graphene is extremely light, its mechanical motion is sensitive to very small electromagnetic forces.

The central objective is to model and control the nonlinear—or quadratic—optomechanical interaction required to prepare mechanical states that cannot be described classically. Such states could support enhanced force and mass sensing, long-lived quantum memories and mechanically encoded quantum information. The student will own a focused theoretical and computational research programme. They will develop analytical and numerical models of the device dynamics and determine how resonator geometry, phononic-crystal design, electrical control, mechanical and electrical quality factors, and linear and quadratic coupling strengths affect device performance.

The research will examine practical limitations including parasitic linear coupling, multimode interference, heating, dissipation and decoherence. These models will be used to identify experimentally achievable operating regimes and translate theoretical results into design rules and fabrication tolerances. The student will also investigate protocols for preparing, controlling and measuring non-classical mechanical states, with possible applications in quantum sensing and quantum information processing.

The project is embedded within the EPSRC-funded Quantum Information with Mechanical Systems programme. The student will work closely with quantum theorists, graphene-device researchers and low-temperature experimental physicists. Their predictions will inform device development at Exeter and, through the wider collaboration, be compared with fabrication, characterisation and cryogenic-measurement results. The student’s primary contribution will be computational; previous nanofabrication experience is not required. However, they will gain interdisciplinary understanding of graphene nanodevices, superconducting circuits and low-temperature quantum measurement. Expected outputs include documented research software, experimentally relevant device-design principles, conference presentations, peer-reviewed publications and a doctoral thesis.

Funded by: EPSRC Engineering and Physical Sciences Research Council