Simone De Liberato's Quantum Theory and Technology group explores quantum electrodynamics in semiconductor systems. Research: (1) ultrastrong and deep-strong light-matter coupling in polariton and circuit QED systems; (2) mid-infrared polariton physics with potential sensing applications; (3) virtual photon condensation and vacuum fluctuations in quantum materials; (4) positronium density measurements using polaritonic effects. Relevant to quantum sensing via strong coupling platforms.