Realizing discontinuous quantum phase transitions in a strongly correlated driven optical lattice
Realizing discontinuous quantum phase transitions in a strongly correlated driven optical lattice
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DOI：
10.1038/s41567-021-01476-w
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发表时间：
2021-05
期刊：
影响因子：
19.6
通讯作者：
B. Song;S. Dutta;S. Bhave;Jr-Chiun Yu;E. Carter;N. Cooper;U. Schneider
中科院分区：
文献类型：
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作者：
B. Song;S. Dutta;S. Bhave;Jr-Chiun Yu;E. Carter;N. Cooper;U. Schneider
不连续（一阶）量子相变和相关的亚稳态在物理学的不同领域发挥着核心作用，从铁磁性到早期宇宙的假真空衰变，然而，它们的动力学还没有得到很好的理解。超冷原子为量子相变的实验模拟提供了一个理想的平台，然而，到目前为止，一级相变的研究仅限于弱相互作用的系统，量子效应被指数抑制。在这里，我们实现了一个强关联驱动的多体系统，其过渡可以从连续到不连续调谐。一维光学晶格的共振振动使两个最低的布洛赫带杂化，驱动从莫特绝缘体到具有交错相序的超流体的新颖转变。对于弱振动振幅，这种过渡是不连续的，系统可以保持冻结在亚稳态，而对于强振动，它经历了一个连续的过渡到超流体。我们对这种亚稳态和滞后现象的观察与数值模拟一致，并为探索量子涨落在不连续跃迁中的关键作用铺平了道路。
Discontinuous (first-order) quantum phase transitions and the associated metastability play central roles in diverse areas of physics, ranging from ferromagnetism to the false-vacuum decay in the early Universe,; yet, their dynamics are not well understood. Ultracold atoms provide an ideal platform for experimental simulations of quantum phase transitions,; so far, however, studies of first-order phase transitions have been limited to systems with weak interactions, , –, where quantum effects are exponentially suppressed. Here we realize a strongly correlated driven many-body system whose transition can be tuned from continuous to discontinuous. Resonant shaking of a one-dimensional optical lattice hybridizes the two lowest Bloch bands,, driving a novel transition from a Mott insulator to a superfluid with a staggered phase order. For weak shaking amplitudes, this transition is discontinuous and the system can remain frozen in a metastable state, whereas for strong shaking, it undergoes a continuous transition towards a superfluid. Our observations of this metastability and hysteresis agree with numerical simulations and pave the way for exploring the crucial role of quantum fluctuations in discontinuous transitions.