Frustrated quantum magnetism with Bose gases in triangular optical lattices at negative absolute temperatures
Frustrated quantum magnetism with Bose gases in triangular optical lattices at negative absolute temperatures
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DOI：
10.1038/s42005-020-0323-5
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发表时间：
2019-08
影响因子：
5.5
通讯作者：
D. Yamamoto;T. Fukuhara;I. Danshita
中科院分区：
文献类型：
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作者：
D. Yamamoto;T. Fukuhara;I. Danshita
具有几何挫折的量子反铁磁体具有丰富的多体物理性质，但难以用经典计算机模拟。尽管分析这类系统的量子模拟研究是可取的，但它们仍然局限于高温区域，在那里有趣的量子效应被抹去了。本文提出了一种可行的方案，利用负绝对温度下光学晶格中的超冷玻色气体，对具有强量子涨落的受挫反铁磁性进行模拟量子模拟。具体地说，我们从数值模拟中表明，负温度态的时间演化受到跳变能量的缓慢扫描，模拟了具有符号反转跳变的受挫玻色-哈伯德模型的量子相变。此外，我们定量地预测了跳跃各向异性三角形晶格中受挫超流体与莫特绝缘子相之间的相界，为量子模拟提供了基准。
Quantum antiferromagnets with geometrical frustration exhibit rich many-body physics but are hard to simulate by means of classical computers. Although quantum-simulation studies for analyzing such systems are thus desirable, they are still limited to high-temperature regions, where interesting quantum effects are smeared out. Here we propose a feasible protocol to perform analog quantum simulation of frustrated antiferromagnetism with strong quantum fluctuations by using ultracold Bose gases in optical lattices at negative absolute temperatures. Specifically, we show from numerical simulations that the time evolution of a negative-temperature state subjected to a slow sweep of the hopping energy simulates quantum phase transitions of a frustrated Bose–Hubbard model with sign-inverted hoppings. Moreover, we quantitatively predict the phase boundary between the frustrated superfluid and Mott-insulator phases for triangular lattices with hopping anisotropy, which serves as a benchmark for quantum simulation.