论文标题
偏斜梯子中的量子相变：纠缠熵和保真度研究
Quantum phase transition in skewed ladders: an entanglement entropy and fidelity study
论文作者
论文摘要
状态的纠缠熵（EE）是复合系统两个部分之间相关性或纠缠的量度，当基态（GS）经历量子相变（QPT）的质量变化时，它可能会显示出明显的变化。因此，EE已被广泛用于表征各种相关的哈密顿人中的QPT。同样，忠诚度在QPT处也显示出急剧变化。我们使用EE和Fidelity分析表征了3/4、3/5和5/7偏斜的梯子，表征了沮丧的抗铁磁Heisenberg Spin-1/2系统的QPT。值得注意的是，可以使用EE和保真度准确地确定这些系统中的所有非磁性QPT边界，并且EE表现出不连续的变化，而富达在过渡点显示出急剧的倾角。还要注意的是，如果是退化的GS，则不对称的计算表明，即使没有实际的相变，即使没有实际的相转换，也会显示出EE的野生波动，但是，通过计算EE和忠诚度来解决此问题的对称子领域的最低能量状态，即归化的状态的最低能量。
Entanglement entropy (EE) of a state is a measure of correlation or entanglement between two parts of a composite system and it may show appreciable change when the ground state (GS) undergoes a qualitative change in a quantum phase transition (QPT). Therefore, the EE has been extensively used to characterise the QPT in various correlated Hamiltonians. Similarly fidelity also shows sharp changes at a QPT. We characterized the QPT of frustrated antiferromagnetic Heisenberg spin-1/2 systems on 3/4, 3/5 and 5/7 skewed ladders using the EE and fidelity analysis. It is noted that all the non-magnetic to magnetic QPT boundary in these systems can be accurately determined using the EE and fidelity, and the EE exhibits a discontinuous change, whereas fidelity shows a sharp dip at the transition points. It is also noted that in case of the degenerate GS, the unsymmetrized calculations show wild fluctuations in the EE and fidelity even without actual phase transition, however, this problem is resolved by calculating the EE and the fidelity in the lowest energy state of the symmetry subspaces, to which the degenerate states belong.
