Doojin Kim (USD), "Quantum Sensing of Radiative Decay Photons with Superconducting Qubits"
CTPU Seminar room
Theory Bldg, 4F
Radiative decays of weakly interacting particles can produce extremely faint photons in the micro-eV range, corresponding to GHz-scale microwave signals. This energy scale naturally matches the transition frequencies of superconducting qubits. In this talk, I will discuss how transmon qubits can be used as resonant quantum sensors for such rare decay photons. Starting from the classical and quantum descriptions of LC resonators, I will explain how Josephson-junction nonlinearity leads to an anharmonic two-level system, how an electromagnetic signal drives Rabi oscillations, and how the resulting transition probability can be converted into an event-rate estimate. I will then discuss sensitivity prospects for radiative decays of dark matter and neutrinos, including possible enhancements from reflective cavities, effective volume scaling, repeated measurements, and collective quantum protocols.