Long coherence times for edge spins
Long coherence times for edge spins
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DOI：
10.1088/1742-5468/aa73f0
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发表时间：
2017-06-01
影响因子：
2.4
通讯作者：
Fendley, Paul
中科院分区：
文献类型：
--
作者：
Kemp, Jack;Yao, Norman Y.;Fendley, Paul
我们发现，在某些一维自旋链与开放的边界条件，边缘自旋保持记忆的初始状态很长一段时间，即使在无限的温度。长的相干时间不需要无序，只需要有序的相位。在可积的伊辛和XYZ链中，强零模的存在意味着相干时间是无限的。当伊辛被破坏可积性的相互作用扰动时，相干时间在扰动耦合中保持指数增长。我们表明，这是一个边缘的“几乎”强零模式，几乎与哈密尔顿交换的后果。我们明确地计算这个算子，使我们能够准确地估计边缘自旋自相关器的平台值。
We show that in certain one-dimensional spin chains with open boundary conditions, the edge spins retain memory of their initial state for very long times, even at infinite temperature. The long coherence times do not require disorder, only an ordered phase. In the integrable Ising and XYZ chains, the presence of a strong zero mode means the coherence time is infinite. When Ising is perturbed by interactions breaking the integrability, the coherence time remains exponentially long in the perturbing couplings. We show that this is a consequence of an edge 'almost' strong zero mode that almost commutes with the Hamiltonian. We compute this operator explicitly, allowing us to estimate accurately the plateau value of edge spin autocorrelator.