哈佛大学Greiner, Markus团队研究了低温状态下的中性原子哈伯德量子模拟器。相关论文发表在2025年6月11日出版的《自然》杂志上。

光学晶格中的超冷费米子原子提供了Hubbard模型的原始实现，这是现代凝聚态物理学的基础。尽管取得了显著进展，但这些光学晶格材料类似物的可接近温度仍然太高，无法解决许多悬而未决的问题。研究组展示了温度的几倍降低，将Hubbard模型的大规模量子模拟带入了一个全新的领域。这是通过动态控制模型参数将低熵积状态转换为强相关的感兴趣状态来实现的，这对经典模拟来说极具挑战性。 

在半填充时，长程反铁磁序接近饱和，导致温度为\（T/T=0.0{5}_{-0.05}^{+0.06}\），这基于与数值精确模拟的比较。掺杂远离半填充，实现系统准确和预测性的数值模拟极具挑战性。重要的是，研究组能够使用量子模拟来确定一种新的途径，通过掺杂实现类似的低温。通过将短程自旋关联与最先进但近似的约束路径辅助场量子蒙特卡罗模拟进行比较，证实了这一点。与铜酸盐相比，报告的温度对应于从远高于室温到低于室温的降低，在室温下可能会出现伪隙和条纹相等物理现象。该工作为量子模拟打开了大门，量子模拟解决了材料科学中的悬而未决的问题，发展了与数值方法和理论研究的协同作用，并导致了新物理学的发现。

附：英文原文

Title: A neutral-atom Hubbard quantum simulator in the cryogenic regime

Author: Xu, Muqing, Kendrick, Lev Haldar, Kale, Anant, Gang, Youqi, Feng, Chunhan, Zhang, Shiwei, Young, Aaron W., Lebrat, Martin, Greiner, Markus

Issue&Volume: 2025-06-11

Abstract: Ultracold fermionic atoms in optical lattices offer pristine realizations of Hubbard models1, which are fundamental to modern condensed-matter physics2,3. Despite notable advancements4,5,6, the accessible temperatures in these optical lattice material analogues are still too high to address many open problems7,8,9,10. Here we demonstrate a several-fold reduction in temperature6,11,12,13, bringing large-scale quantum simulations of the Hubbard model into an entirely new regime. This is accomplished by transforming a low-entropy product state into strongly correlated states of interest via dynamic control of the model parameters14,15, which is extremely challenging to simulate classically10. At half-filling, the long-range antiferromagnetic order is close to saturation, leading to a temperature of (T/t=0.0{5}_{-0.05}^{+0.06}) based on comparisons with numerically exact simulations. Doped away from half-filling, it is exceedingly challenging to realize systematically accurate and predictive numerical simulations9. Importantly, we are able to use quantum simulation to identify a new pathway for achieving similarly low temperatures with doping. This is confirmed by comparing short-range spin correlations to state-of-the-art, but approximate, constrained-path auxiliary-field quantum Monte Carlo simulations16,17,18. Compared with the cuprates2,19,20, the reported temperatures correspond to a reduction from far above to below room temperature, at which physics such as the pseudogap and stripe phases may be expected3,19,21,22,23,24. Our work opens the door to quantum simulations that solve open questions in material science, develop synergies with numerical methods and theoretical studies, and lead to discoveries of new physics8,10.

DOI: 10.1038/s41586-025-09112-w

Source: https://www.nature.com/articles/s41586-025-09112-w