Fig. 3: Experimental protocol for implementing dynamical state preparation and stabilization of the driven-dissipative system.
a Top: schematic representing the rotation of the qubit eigenbasis in the presence of a detuned drive applied to the qubit. Center: representation of pure dephasing in the dressed basis. Bottom: representation of competing decay rates in the dressed qubit basis. By tailoring the coupling of the qubit to the frequency-dependent phonon bath, we are able to control the relative size of γ± as a function of qubit frequency. b Measurement of qubit loss Γq = 1/T1 versus frequency (blue). The red curve is a fit to Eq. (1) showing that the variation in the qubit loss is dictated by conversion into SAW phonons. The green curve is a result of the coupling-of-modes model for the electrical conductance of the SAW resonator with no fit parameters (see Supplementary Note 1). The arrow indicates the frequency at which the bath engineering experiments are performed. The black dashed lines are the endpoints of experimentally accessible Mollow triplet sidebands. c Pulse sequence for investigating the coherence of the driven-dissipative quantum acoustics system. d Tomographic reconstruction of qubit state evolution at a resonant Rabi frequency of Ω/(2π) = 8.47 MHz and drive detuning Δ/(2π) = − 10 MHz. Dots represent the experimental data while the dashed lines are solutions to Eq. (2) with the same drive parameters, which correspond to γ+ = 3.4 μs−1 and γ− = 1.3 μs−1. e Measurement of the state purity as a function of time. In the combined presence of phonon loss and drive the purity reaches a value of 0.85 at t = 1 μs, in contrast to a maximally mixed state represented by the dashed line at \({{{{{{{\mathcal{P}}}}}}}}=0.5\). The solid red line is the expected state purity based on Eq. (2).
