Controlling qubit-oscillator systems using linear parameter sweeps

作者：Sahel Ashhab, Tomoko Fuse, Fumiki Yoshihara, Sunmi Kim, Kouichi Semba · 发表于：New Journal of Physics · 年份：2023 · DOI：10.1088/1367-2630/acf2b9 · 被引用次数：4 · 研究领域：Quantum Information and Cryptography、Quantum Mechanics and Applications、Spectroscopy and Quantum Chemical Studies

Abstract We investigate the dynamics of a qubit-oscillator system under the influence of a linear sweep of system parameters. We consider two main cases. In the first case, we consider sweeping the parameters between the regime of a weakly correlated ground state and the regime of a strongly correlated ground state, a situation that can be viewed as a finite-duration quench between two phases of matter: the normal phase and the superradiant phase. Excitations are created as a result of this quench. We investigate the dependence of the excitation probabilities on the various parameters. We find a qualitative asymmetry in the dynamics between the cases of a normal-to-superradiant and superradiant-to-normal quench. The second case of parameter sweeps that we investigate is the problem of a Landau–Zener sweep in the qubit bias term for a qubit coupled to a harmonic oscillator. We analyze a theoretical formula based on the assumption that the dynamics can be decomposed into a sequence of independent Landau–Zener transitions. In addition to establishing the conditions of validity for the theoretical formula, we find that under suitable conditions, deterministic and robust multi-photon state preparation is possible in this system.