Cohadon and Heidmann co-lead the Optomechanics and Quantum Measurements group at LKB. Research directions: (1) Back-action evasion and Standard Quantum Limit (SQL) — early demonstration of radiation-pressure back-action in a micro-mirror (Nature 2006), subsequent beating of SQL via quantum correlations; (2) Micro/nanomechanical resonators — 2D photonic crystal deformable slabs, membrane-in-the-middle cavities, micropillar resonators for radiation-pressure optomechanics; (3) Superconducting qubit–macroscopic membrane coupling — Jacqmin & Deléglise team: resonant coupling of transmon qubit to MHz membrane oscillator, tracking quantum motion with 300 repeated interactions (2025); high-impedance hyperinductors for electromechanics; (4) Gravitational wave detector contributions — VIRGO/LIGO data analysis and quantum noise modeling. Applications include back-action-evading force sensing and tests of quantum mechanics at macroscopic scales.
Croot returned from Princeton to found Sydney's Superconducting Quantum Circuits Laboratory. The programme uses superconducting circuits both as quantum processors and as extremely sensitive probes: coupling microwave resonators and qubits to other degrees of freedom (mechanical modes, semiconductor structures, spins) to build hybrid systems, and developing the quantum-limited amplification chain that makes single-microwave-photon detection possible. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — superconducting circuits are the principal competitor technology for detecting the weak microwave signals that NV ensembles read magnetically; a quantum-limited or squeezed microwave amplifier is what lets an inductively-detected spin ensemble reach — and beat — the pT/sqrt(Hz) regime. Newly established, well-equipped lab; high autonomy for a postdoc and active recruitment as the lab builds out.