Amplification and attenuation of a probe signal by doubly-dressed states

Understand

We analyse a system composed of a qubit coupled to electromagnetic fields of two high quality quantum oscillators.

• Particular realization of such a system is the superconducting qubit coupled to a transmission-line resonator driven by two signals with frequencies close to the resonator's harmonics.
• One strong signal is used for exciting the system to a high energetic state while the second weak signal is applied for probing effective eigenstates of the system.
• We demonstrate that a description of the system dynamics as doubly dressed qubit is applicable.