Destruction of string order after a quantum quench
Destruction of string order after a quantum quench
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量子淬灭后弦序的破坏
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
R. Fazio
中科院分区：
文献类型：
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作者：
Marcello Calvanese Strinati;L. Mazza;M. Endres;D. Rossini;R. Fazio
我们研究了自旋为1的链在量子猝灭后的弦序演化。在初始化的阿弗莱克-肯尼迪-利布-田崎状态链后，我们详细分析了如何字符串顺序演变为时间的函数，在不同的长度尺度。选择猝灭后的哈密顿量来保持或突然破坏对称性，这确保了弦序的存在。取决于这两种情况中的哪一种出现，弦的有序性在热力学极限下的无穷小时间内要么被保持，要么被丢失。非定域序可能突然被破坏，我们称之为弦序熔化，这一事实使它与典型的朗道序参量有质的不同。这种情况的特点是彻底的数值模拟的基础上矩阵产品状态算法和分析研究的基础上，几个简化模型的短时间扩展。
We investigate the evolution of string order in a spin-1 chain following a quantum quench. After initializing the chain in the Affleck-Kennedy-Lieb-Tasaki state, we analyze in detail how string order evolves as a function of time at different length scales. The Hamiltonian after the quench is chosen either to preserve or to suddenly break the symmetry which ensures the presence of string order. Depending on which of these two situations arises, string order is either preserved or lost even at infinitesimal times in the thermodynamic limit. The fact that nonlocal order may be abruptly destroyed, what we call string-order melting, makes it qualitatively different from typical order parameters in the manner of Landau. This situation is thoroughly characterized by means of numerical simulations based on matrix product states algorithms and analytical studies based on a short-time expansion for several simplified models.