FIG. 8.

Exact solution versus Born-Markov approximation. Here, the red lines are the exact solution while the blue lines are the Born-Markov approximation. The dashed black lines mark the band edge and the thick black line is the bare qubit frequency. Here, we take ω₀ = 7.8 GHz, α = 1.155 GHz, and g = 0.5275 GHz. (a) Single qubit. (b) Two qubits for |z₁ − z₂| = 1. (c) Theoretical photon population of the bound states. (d) Linewidth ratio of the two bound states as a function of bound-state energy. (e) Avoided crossing on resonance versus bare qubit frequency. We see that the experimental data are well described by the Markovian solution only deep in the gap.