Simulating the Response of Quantum Devices for Dark Matter Searches

Quantum sensors could provide unique promise as particle detectors, especially for dark matter searches, due to their sensitivity to low-energy processes. To fully simulate superconducting quantum devices as particle detectors, we need to understand (1) how particles deposit energy, (2) how energy (in the form of phonons) propagates in the detector, and (3) how quantum processes in the detector produce an observable readout signal. While (1) is handled by the GEANT4 simulation toolkit, and (2) by the G4CMP software, the Quantum Device Response (QDR) package models the quantum physics that underlies the response of quantum sensors such as transmon qubits and phonon-mediated Microwave Kinetic Inductance Detectors (MKIDs). MKIDs, which are superconducting microresonators commonly used in astronomy, are attractive candidates for sub-GeV particle dark matter searches given their potential sensitivity to sub-eV quanta and their native frequency-domain multiplexibility. This presentation will focus on the process of simulating the response of phonon-mediated MKIDs by mapping phonon energy deposits from G4CMP to realistic detector readout signals. In this talk, we will present on building out this critical last stage of the simulation chain.