Fig. 2
Resonant interaction. The schematics at the top of the graphs indicate the energy levels of the RX qubit (\({\nu }_{{\rm{RX}}}\)), coupling resonator (\({\nu }_{{\rm{C}}}\)) and transmon (\({\nu }_{{\rm{T}}}\)). Theory curves in the absence (presence) of coupling are shown as dashed black (red) lines. a Reflected amplitude \(| {S}_{11}|\) as a function of RX detuning \(\it \Delta\) and probe frequency \({\nu }_{{\rm{p}}}\) for RX qubit tunnel coupling configuration 2. b Reflected amplitude \(| {S}_{11}|\) as a function of relative transmon (Tmon) flux \({\it{\Phi} }_{{\rm{T}}}/{\it{\Phi} }_{0}\) and \({\nu }_{{\rm{p}}}\). The states \(\left|\pm \right\rangle\) are discussed in the main text. c Cuts from panel a at \({\it{\Delta}} /h\simeq -7.6\ {\rm{GHz}}\) (black) and from panel b at \({\it{\Phi} }_{{\rm{T}}}/{\it{\Phi} }_{0}\simeq 0.3\) (green) as marked with arrows in the respective panels. The black trace is offset in \(| {S}_{11}|\) by 0.1. Theory fits are shown as red dashed lines. d \(| {S}_{11}|\) as a function of \({\it{\Delta}}\) and \({\nu }_{{\rm{p}}}\) for RX qubit tunnel coupling configuration 2. The states \(\left|-,\pm \right\rangle\) and \(\left|+,\pm \right\rangle\) are explained in the main text. The black and blue arrows are referred to in f, the purple arrow is discussed in the text. e Result of master equation simulation for parameters as in d. The values for \(| {S}_{11}|\) are scaled to the experimental data range in d. f \(| {S}_{11}({\nu }_{{\rm{p}}})|\) at \({\it{\Delta}} /h\simeq -9.8\ {\rm{GHz}}\) and \({\it{\Delta}} /h\simeq -5.6\ {\rm{GHz}}\) as marked with the corresponding colored arrows in panels d, e. The blue trace is offset in \(| {S}_{11}|\) by 0.2
