论文标题
N-Tupling离散时间晶体的相图和最佳控制
Phase diagram and optimal control for n-tupling discrete time crystal
论文作者
论文摘要
时间晶体的出现是自发打破时间平移对称性的显着结果。在定期驱动的系统中,可以实现离散时间晶体(DTC),其周期性是驾驶期的N倍。但是,所有实验观察均已进行周期倍加倍和周期分离的离散时间晶体。可以通过在时域中模拟多体物理学来产生新颖的物理学,这需要对N-Tupling DTC进行真正的实现。超冷的玻色子原子系统在振荡镜上共鸣是可以实现大时DTC的模型之一。 DTC的制备需要控制超冷骨气原子的初始分布以及镜频率。在这项工作中,我们证明了这种DTC与对原子的初始分布的扰动是可靠的。我们展示了如何使用贝叶斯方法在制备初始状态以及有效计算此类模型的相位图时增强控制。此外,我们通过分析量子多体波动来检查DTC的稳定性,并表明它们没有揭示加热的特征。
A remarkable consequence of spontaneously breaking the time translational symmetry in a system, is the emergence of time crystals. In periodically driven systems, discrete time crystals (DTC) can be realized which have a periodicity that is n times the driving period. However, all of the experimental observations have been performed for period-doubling and period-tripling discrete time crystals. Novel physics can arise by simulating many-body physics in the time domain, which would require a genuine realisation of the n-tupling DTC. A system of ultra-cold bosonic atoms bouncing resonantly on an oscillating mirror is one of the models that can realise large period DTC. The preparation of DTC demands control in creating the initial distribution of the ultra-cold bosonic atoms along with the mirror frequency. In this work, we demonstrate that such DTC is robust against perturbations to the initial distribution of atoms. We show how Bayesian methods can be used to enhance control in the preparation of the initial state as well as to efficiently calculate the phase diagram for such a model. Moreover, we examine the stability of DTCs by analyzing quantum many-body fluctuations and show that they do not reveal signatures of heating.