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arXiv 2104.15070cond-mat.stat-mech
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长程量子伊辛模型的温度临界行为

Finite-temperature critical behavior of long-range quantum Ising models

E. Gonzalez-Lazo, M. Heyl, M. Dalmonte, A. Angelone

摘要:

我们研究了具有长程铁磁相互作用的量子伊辛链的相图和临界性质,该链以指数为$α$的幂律方式衰减,处于当前捕获离子实验直接感兴趣的状态。使用大规模路径积分蒙特卡罗模拟,我们调查的基态和非零温度制度。我们确定的铁磁相的相边界,并获得准确的估计的铁磁-顺磁转变温度。我们进一步确定各自的过渡的临界指数。我们的结果是在协议与现有的预测相互作用指数$α> 1$的一些临界指数的小偏差。我们还解决了难以捉摸的制度$α< 1$,在那里我们发现,基态和非零温度过渡的普适性类是一致的平均场极限在$α= 0$。我们的工作不仅有助于理解的平衡性质的远程相互作用量子伊辛模型,但也可以是重要的解决基本的动力学方面,如有关问题的公开问题的热化在这样的模型。

英文摘要:

We study the phase diagram and critical properties of quantum Ising chains with long-range ferromagnetic interactions decaying in a power-law fashion with exponent $α$, in regimes of direct interest for current trapped ion experiments. Using large-scale path integral Monte Carlo simulations, we investigate both the ground-state and the nonzero-temperature regimes. We identify the phase boundary of the ferromagnetic phase and obtain accurate estimates for the ferromagnetic-paramagnetic transition temperatures. We further determine the critical exponents of the respective transitions. Our results are in agreement with existing predictions for interaction exponents $α> 1$ up to small deviations in some critical exponents. We also address the elusive regime $α< 1$, where we find that the universality class of both the ground-state and nonzero-temperature transition is consistent with the mean-field limit at $α= 0$. Our work not only contributes to the understanding of the equilibrium properties of long-range interacting quantum Ising models, but can also be important for addressing fundamental dynamical aspects, such as issues concerning the open question of thermalization in such models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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