Erba V, Pastore M, Rotondo P
Dipartimento di Fisica dell' Università degli Studi di Milano, via Celoria 16, 20100 Milano, Italy.
Istituto Nazionale di Fisica Nucleare, sezione di Milano, via Celoria 16, 20100 Milano, Italy.
Phys Rev Lett. 2021 May 7;126(18):183601. doi: 10.1103/PhysRevLett.126.183601.
We provide strong evidence that the effective spin-spin interaction in a multimodal confocal optical cavity gives rise to a self-induced glassy phase, which emerges exclusively from the peculiar Euclidean correlations and is not related to the presence of disorder as in standard spin glasses. As recently shown, this spin-spin effective interaction is both nonlocal and nontranslational invariant, and randomness in the atoms' positions produces a spin glass phase. Here we consider the simplest feasible disorder-free setting, where atoms form a one-dimensional regular chain and we study the thermodynamics of the resulting effective Ising model. We present extensive results showing that the system has a low-temperature glassy phase. The model depends on the adimensional parameter α=(a/w_{0})^{2}, a being a lattice spacing and w_{0} an interaction length scale. Notably, for rational values of α=p/q, the number of metastable states at low temperature grows exponentially with q and the problem of finding the ground state rapidly becomes computationally intractable, suggesting that the system develops high-energy barriers and ergodicity breaking occurs.
我们提供了有力证据，证明多模共焦光学腔中的有效自旋-自旋相互作用会产生一种自诱导玻璃相，这种玻璃相完全源自特殊的欧几里得关联，与标准自旋玻璃中因无序而产生的情况无关。正如最近所表明的，这种自旋-自旋有效相互作用既非局域的，也不具有平移不变性，原子位置的随机性会产生一个自旋玻璃相。在这里，我们考虑最简单可行的无无序设定，即原子形成一维规则链，并且我们研究由此产生的有效伊辛模型的热力学。我们给出了大量结果，表明该系统具有低温玻璃相。该模型取决于无量纲参数α=(a/w₀)²，其中a是晶格间距，w₀是相互作用长度尺度。值得注意的是，对于α = p/q的有理数值，低温下亚稳态的数量随q呈指数增长，并且找到基态的问题很快就会在计算上变得难以处理，这表明系统形成了高能垒并且发生了遍历性破坏。
