Fregosi Alessandro, Marinelli Carmela, Gabbanini Carlo, Bevilacqua Giuseppe, Biancalana Valerio, Arimondo Ennio, Fioretti Andrea
Istituto Nazionale di Ottica, CNR-INO, Sede Secondaria di Pisa, Via G. Moruzzi 1, 56124, Pisa, Italy.
Dip. di Scienze Fisiche, della Terra e dell'Ambiente, Università degli Studi di Siena, Via Roma 56, 53100, Siena, Italy.
Sci Rep. 2023 Sep 18;13(1):15304. doi: 10.1038/s41598-023-41693-2.
The application of a periodic nonresonant drive to a system allows the Floquet engineering of effective fields described by a broad class of quantum simulated Hamiltonians. The Floquet evolution is based on two different elements. The first one is a time-independent or stroboscopic evolution with an effective Hamiltonian corresponding to the quantum simulation target. The second element is the time evolution at the frequencies of the nonresonant driving and of its harmonics, denoted as micromotion. We examine experimentally and theoretically the harmonic dual-dressing Floquet engineering of a cold atomic two-level sample. Our focus is the dressing operation with small bare energies and large Rabi frequencies, where frequencies and amplitudes of the stroboscopic/micromotion time evolutions are comparable. At the kHz range of our dressed atom oscillations, we probe directly both the stroboscopic and micromotion components of the qubit global time evolution. We develop ad-hoc monitoring tools of the Floquet space evolution. The direct record of the time evolution following a pulsed excitation demonstrates the interplay between the two components of the spin precession in the Floquet space. From the resonant pumping of the dressed system at its evolution frequencies, Floquet eigenenergy spectra up to the fifth order harmonic of the dressing frequency are precisely measured as function of dressing parameters. Dirac points of the Floquet eigenenergies are identified and, correspondingly, a jump in the dynamical phase shift is measured. The stroboscopic Hamiltonian eigenfrequencies are measured also from the probe of the micromotion sidebands.These monitoring tools are appropriate for quantum simulation/computation investigations. Our results evidence that the stroboscopic phase shift of the qubit wavefunction contains an additional information that opens new simulation directions.
将周期性非共振驱动应用于一个系统，可以实现由一大类量子模拟哈密顿量所描述的有效场的弗洛凯工程。弗洛凯演化基于两个不同的要素。第一个是与量子模拟目标相对应的含有效哈密顿量的与时间无关的或频闪演化。第二个要素是在非共振驱动频率及其谐波频率下的时间演化，称为微运动。我们通过实验和理论研究了冷原子二能级样本的谐波双缀饰弗洛凯工程。我们关注的是具有小裸能和大拉比频率的缀饰操作，其中频闪/微运动时间演化的频率和幅度是可比的。在我们的缀饰原子振荡的千赫兹范围内，我们直接探测量子比特全局时间演化的频闪和微运动分量。我们开发了用于监测弗洛凯空间演化的专用工具。对脉冲激发后的时间演化的直接记录展示了弗洛凯空间中自旋进动的两个分量之间的相互作用。通过在其演化频率下对缀饰系统进行共振泵浦，精确测量了高达缀饰频率五阶谐波的弗洛凯本征能谱作为缀饰参数的函数。确定了弗洛凯本征能的狄拉克点，并相应地测量了动态相移的跃变。频闪哈密顿量本征频率也从微运动边带的探测中测得。这些监测工具适用于量子模拟/计算研究。我们的结果表明，量子比特波函数的频闪相移包含了可开辟新模拟方向的额外信息。
