Fig. 4: Two-tone parametric modulation.
From: Rapid and unconditional parametric reset protocol for tunable superconducting qubits
a Jaynes-Cummings ladder diagram of the two-tone parametric modulation process. \(\left|g\right\rangle\), \(\left|e\right\rangle\), \(\left|f\right\rangle\) and \(\left|0\right\rangle\), \(\left|1\right\rangle\) denote the lowest energy states of the qubit and resonator, respectively. The dashed pale red and green circles represent one of the sideband modes induced by the parametric modulation. The dashed arrow labeled κr illustrates the decay process of the resonator. b Scan map of the \(\left|e\right\rangle\) population after 1000 ns two-tone parametric modulation. Before modulation, the qubit was prepared in the \(\left|f\right\rangle\) state. Blue and yellow strips correspond to the \(\left|f,0\right\rangle \to \left|e,1\right\rangle \to \left|e,0\right\rangle\) and \(\left|e,0\right\rangle \to \left|g,1\right\rangle \to \left|g,0\right\rangle\) decay processes, respectively. c Master equation simulation with experimental parameters from b. Time evolution of each qubit state, with the qubit initially prepared as \(\left|e\right\rangle\) (d) or \(\left|f\right\rangle\) (e), and then reset with two-tone modulation. Inset figure in e is the IQ plot of each state. f Time evolution of all remaining excited states (1 − Pg). The gray dashed line is the readout floor.
