From Adiabatic to Dispersive Readout of Quantum Circuits

PARK, SUNGHUN; METZGER, C.; TOSI, L.; GOFFMAN, M.F.; URBINA, C.; POTHIER, H.; YEYATI, A. LEVY

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2020 vol. 125

0031-9007

Spectral properties of a quantum circuit are efficiently read out by monitoring the resonance frequency shift it induces in a microwave resonator coupled to it. When the two systems are strongly detuned, theory attributes the shift to an effective resonator capacitance or inductance that depends on the quantum circuit state. At small detuning, the shift arises from the exchange of virtual photons, as described by the Jaynes-Cummings model. Here we present a theory bridging these two limits and illustrate, with several examples, its necessity for a general description of quantum circuits readout.