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arXiv quant-ph/0202162quant-phcond-mat
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简单量子相变中的纠缠

Entanglement in a simple quantum phase transition

Tobias J. Osborne, Michael A. Nielsen

摘要:

自然发生的物理系统在热平衡时存在什么纠缠?大多数这样的系统是棘手的,它是可取的,研究简单,但现实的系统,可以解决。这种系统的一个例子是一维无限晶格各向异性XY模型。该模型是完全可解的使用乔丹-维格纳变换,它是可能的,计算两个网站的约化密度矩阵的所有网站对。利用双位密度矩阵,计算了任意两个位之间在所有参数值和温度下的形成纠缠。我们还研究了XY模型的一种特殊情况,横截面伊辛模型中的纠缠,它表现出量子相变。结果表明,次近邻纠缠(虽然不是最近邻纠缠)在临界点处达到最大值。此外,我们表明,在横向伊辛模型的临界点对应于一个单一的网站和晶格的其余部分之间的纠缠行为的过渡。

英文摘要:

What entanglement is present in naturally occurring physical systems at thermal equilibrium? Most such systems are intractable and it is desirable to study simple but realistic systems which can be solved. An example of such a system is the 1D infinite-lattice anisotropic XY model. This model is exactly solvable using the Jordan-Wigner transform, and it is possible to calculate the two-site reduced density matrix for all pairs of sites. Using the two-site density matrix, the entanglement of formation between any two sites is calculated for all parameter values and temperatures. We also study the entanglement in the transverse Ising model, a special case of the XY model, which exhibits a quantum phase transition. It is found that the next-nearest neighbour entanglement (though not the nearest-neighbour entanglement) is a maximum at the critical point. Furthermore, we show that the critical point in the transverse Ising model corresponds to a transition in the behaviour of the entanglement between a single site and the remainder of the lattice.

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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