Slowest local operators in quantum spin chains
Slowest local operators in quantum spin chains
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DOI：
10.1103/physreve.92.012128
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发表时间：
2015-07-22
影响因子：
2.4
通讯作者：
Huse, David A.
中科院分区：
文献类型：
--
作者：
Kim, Hyungwon;Banuls, Mari Carmen;Huse, David A.
我们在一个不可积的自旋1/2链中数值构造了缓慢松弛的局部算子。限制支持的运营商的M个连续的自旋沿着的链，我们穷尽搜索的运营商，最小化Frobenius范数的交换子与哈密顿量。我们首先表明，Frobenius规范的边界的时间尺度的运营商在高温下放松。我们发现运营商的松弛速度显着低于最慢的简单的“流体动力学”模式，由于能量扩散。然后我们研究了非平凡慢算子的一些性质。使用穷举搜索和张量网络技术，我们发现类似的缓慢放松的运营商的Floquet自旋链，这个系统是流体动力学的“平凡”，没有守恒定律限制他们的动态。我们认为，这种缓慢的放松可能是一个通用的功能，从地方和统一。
We numerically construct slowly relaxing local operators in a nonintegrable spin-1/2 chain. Restricting the support of the operator to M consecutive spins along the chain, we exhaustively search for the operator that minimizes the Frobenius norm of the commutator with the Hamiltonian. We first show that the Frobenius norm bounds the time scale of relaxation of the operator at high temperatures. We find operators with significantly slower relaxation than the slowest simple "hydrodynamic" mode due to energy diffusion. Then we examine some properties of the nontrivial slow operators. Using both exhaustive search and tensor network techniques, we find similar slowly relaxing operators for a Floquet spin chain; this system is hydrodynamically "trivial," with no conservation laws restricting their dynamics. We argue that such slow relaxation may be a generic feature following from locality and unitarity.