论文标题
估计扰动的J1-J2 Heisenberg量子链的相变，地面和首次激发态
Estimating phase transition of perturbed J1-J2 Heisenberg quantum chain in mixtures of ground and first excited states
论文作者
论文摘要
我们表明，J1 -J2 Heisenberg量子自旋链的地面和首先激发态的最接近纠缠（一个次态状态）可以用作订单参数，以检测链条从无间隙自旋流体到间隙二聚体相位的链相变。我们研究了在不同系统尺寸的次级状态下地面和第一个激发状态之间不同相对混合概率不同的相对混合概率的有效性，并将结果推断为热力学极限。我们观察到，即使系统处于基态，最近的邻居并发也可以发挥良好的订单参数的作用，但泄漏到第一个激发态的有限概率很小。此外，我们将次级状态的顺序参数应用于模型的相位图上对单独引入和玻璃疾病的单独介绍的响应，并分析了前一种情况中相应的有限尺寸尺度指数以及相应的有限尺寸尺度指数和新兴的三级政治点。各向异性J1-J2链具有更丰富的相图，也可以使用相同的顺序参数可以清楚地看到。
We show that the nearest neighbour entanglement in a mixture of ground and first excited states - a subjacent state - of the J1-J2 Heisenberg quantum spin chain can be used as an order parameter to detect the phase transition of the chain from a gapless spin fluid to a gapped dimer phase. We study the effectiveness of the order parameter for varying relative mixing probabilities between the ground and first excited states in the subjacent state for different system sizes, and extrapolate the results to the thermodynamic limit. We observe that the nearest neighbour concurrence can play a role of a good order parameter even if the system is in the ground state, but with a small finite probability of leaking into the first excited state. Moreover, we apply the order parameter of the subjacent state to investigate the response to separate introductions of anisotropy and of glassy disorder on the phase diagram of the model, and analyse the corresponding finite-size scale exponents and the emergent tricritical point in the former case. The anisotropic J1-J2 chain has a richer phase diagram which is also clearly visible by using the same order parameter.
