Two-photon lasing by a superconducting qubit

Abstract

We study the response of a magnetic-field-driven superconducting qubit\nstrongly coupled to a superconducting coplanar waveguide resonator. We observed\na strong amplification/damping of a probing signal at different resonance\npoints corresponding to a one and two-photon emission/absorption. The sign of\nthe detuning between the qubit frequency and the probe determines whether\namplification or damping is observed. The larger blue detuned driving leads to\ntwo-photon lasing while the larger red detuning cools the resonator. Our\nexperimental results are in good agreement with the theoretical model of qubit\nlasing and cooling at the Rabi frequency.\n