Evidence of 1.5 THz single-photon detection in quantum capacitance detectors via telegraph rate distribution asymmetry

Abstract

Quantum Capacitance Detectors (QCDs) are shot noise limited terahertz detectors. Radiation breaks Cooper pairs, causing quasiparticle poisoning of a charge qubit, read out by a microwave resonator. We find asymmetry in the distribution of telegraph transition rates, interpreted as resulting from discrete single-photon events.