Time Crystals Protected by Floquet Dynamical Symmetry in Hubbard Models
Time Crystals Protected by Floquet Dynamical Symmetry in Hubbard Models
复制标题
哈伯德模型中受 Floquet 动力学对称性保护的时间晶体
DOI：
10.1103/physrevlett.125.060601
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发表时间：
2020
影响因子：
8.6
通讯作者：
Ikeda Tatsuhiko N.
中科院分区：
文献类型：
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作者：
Chinzei Koki;Ikeda Tatsuhiko N.
我们研究了时间周期驱动系统中的一种非常规对称性，即Floquit动力学对称性(FDS)。与通常的对称性不同，FDS给出了在Floquit谱中等距离的对称扇区，并保护它们之间的量子相干性不受耗散和退相的影响，从而产生了两种时间晶体：离散时间晶体和离散时间准晶，它们在时间上具有不同的周期。结果表明，在交变电场作用下，这些时间晶体出现在玻色-哈伯德模型和费米-哈伯德模型中，其周期只能通过调节电场强度来调节。这些时间晶体只由FDS产生，因此只要FDS受到尊重，它们就会出现在耗散和孤立的系统中，并在无序存在的情况下出现。我们讨论了它们在冷原子实验中的实验实现以及对非对称Hubbard模型的推广。
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-symmetric Hubbard models.