Fig. 2: Circuit 2, and the junction radiation spectrum.
From: Quantum theory of Bloch oscillations in a resistively shunted transmon
a In circuit 2, a transmon is coupled to the Josephson junction array with a low-frequency impedance R. The voltage V is measured at the same port at which the current I is supplied. Because of the current-induced Bloch oscillations, transmon emits waves into the array. b Power spectrum of the emitted waves ωS(ω) is broad-band. Bloch oscillation frequency Ω = πI/e sets a characteristic frequency of an emitted photon, as well as the position of a threshold in the dependence of ωS(ω) on ω. The curve is produced using Eq. (30) for K = 1/8.
