Speaker
Description
Speaker: Doojin Kim
Abstract: 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.