论文标题
在哈伯德模型中受Floquet动力对称保护的时间晶体
Time Crystals Protected by Floquet Dynamical Symmetry in Hubbard Models
论文作者
论文摘要
我们研究了时间周期驱动的系统（Floquet Dynamical Symmetry（FDS））中的非常规的对称性。与通常的对称性不同，FD给出了对称扇区，这些扇区在Floquet频谱中等距，并保护它们之间的量子相干性免受耗散和驱动的影响，从而导致两种时间晶体：离散的时间晶体和离散的时间Quasrystal具有不同时间的周期性。我们表明，这些时间晶体出现在交流场下的玻色和费米 - 哈伯德模型中，并且只能通过调节磁场强度来调整它们的周期性。这些时间晶体仅来自FD，因此出现在耗散和孤立的系统中，并且只要受到FD的尊重而存在。我们讨论了他们在冷原子实验中的实验实现以及对SU（$ n $） - 对称Hubbard模型的概括。
We investigate an unconventional symmetry in time-periodically driven systems, the Floquet dynamical symmetry (FDS). Unlike the usual symmetries, the FDS gives symmetry sectors that are equidistant in the Floquet spectrum and protects quantum coherence between them from dissipation and dephasing, leading to two kinds of time crystals: the discrete time crystal and discrete time quasicrystal that have different periodicity in time. We show that these time crystals appear in the Bose- and Fermi-Hubbard models under ac fields and their periodicity can be tuned only by adjusting the strength of the field. These time crystals arise only from the FDS and thus appear in both dissipative and isolated systems and in the presence of disorder as long as the FDS is respected. We discuss their experimental realizations in cold atom experiments and generalization to the SU($N$)-symmetric Hubbard models.
