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.

具有几何受挫性的量子反铁磁体具有丰富的多体物理原理，但是很难通过经典计算机来模拟。尽管因此需要用于分析此类系统的量子模拟研究，但它们仍限于高温区域，在该区域会抹去有趣的量子效应。在这里，我们提出了一种可行的协议，可以通过在负绝对温度下使用光学晶格中的超冷玻色气体对具有强烈量子波动的受挫反铁磁性进行模拟量子模拟。具体而言，我们从数值模拟中看到，负温度状态的时间演化受到跳变能量的缓慢扫描，可以模拟沮丧的Bose-Hubbard模型的量子相变，其符号反转。此外，