Instituto de Física, Universidade Federal de Alagoas 57072-970 Maceió, Alagoas, Brazil.
Instituto Federal do Piauí, Campus Pedro II, 64255-000 Pedro II-Piauí, Brazil.
Phys Rev E. 2018 May;97(5-1):052115. doi: 10.1103/PhysRevE.97.052115.
The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.
在一个完全可解的伊辛-哈伯德梯中研究了费米子纠缠的程度，其中涉及到在梯级上的 Hubbard 二聚体上的相互作用电子， Hubbard 二聚体在每个梯级上占据半填充，考虑了梯级内跃迁和库仑项。假设相邻 Hubbard 二聚体之间的耦合具有伊辛型性质。基态相图由四个不同的区域组成，分别对应于饱和顺磁相、经典反铁磁相、量子反铁磁相和混合经典-量子相。我们已经精确地计算了费米子纠缠度，它衡量了梯级上电子对之间量子纠缠的程度。详细研究了跃迁幅度、库仑项、温度和磁场对费米子纠缠的影响。结果表明，当量子纠缠在高于经典饱和顺磁基态的中等温度下产生时，费米子纠缠度会出现再入行为。
