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arXiv · 2411.18167

Quantum annealing of a frustrated magnet

Yuqian Zhao·Zhaohua Ma·Zhangzhen He·Haijun Liao·Yan-Cheng Wang·Junfeng Wang·Yuesheng Li
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Abstract

Quantum annealing, which involves quantum tunnelling among possible solutions, has state-of-the-art applications not only in quickly finding the lowest-energy configuration of a complex system, but also in quantum computing. Here we report a single-crystal study of the frustrated magnet $\alpha$-CoV$_2$O$_6$, consisting of a triangular arrangement of ferromagnetic Ising spin chains without evident structural disorder. We observe quantum annealing phenomena resulting from time-reversal symmetry breaking in a tiny transverse field. Below $\sim$ 1 K, the system exhibits no indication of approaching the lowest-energy state for at least 15 hours in zero transverse field, but quickly converges towards that configuration with a nearly temperature-independent relaxation time of $\sim$ 10 seconds in a transverse field of $\sim$ 3.5 mK. Our many-body simulations show qualitative agreement with the experimental results, and suggest that a tiny transverse field can profoundly enhance quantum spin fluctuations, triggering rapid quantum annealing process from topological metastable Kosterlitz-Thouless phases, at low temperatures.

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Yuqian Zhao, Zhaohua Ma, Zhangzhen He, Haijun Liao, Yan-Cheng Wang, Junfeng Wang, Yuesheng Li. 2024-11-27. Quantum annealing of a frustrated magnet. https://doi.org/10.1038/s41467-024-47819-y

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