论文标题
磁场中活性有偏见模型的动力学相变
Dynamical phase transitions for the activity biased Ising model in a magnetic field
论文作者
论文摘要
对于在磁场存在的情况下，我们认为动态活动的较大偏差（定义为在时间间隔内的构型总数变化）。我们确定了几个动态相变，这些跃迁是活动的缩放累积生成函数中的奇异性。特别是，我们发现低活动性铁磁状态和一个新型的高活动阶段，并具有相关的一阶和二阶过渡。高活动阶段对磁场具有负敏感性。在平均场情况下，我们分析了在一阶过渡线上发生的动态相共存，包括重现相关大偏差的最佳控制力。在一维模型中，我们使用精确的对角和克隆方法来对非零磁场处的一阶相变的有限尺寸缩放。
We consider large deviations of the dynamical activity -- defined as the total number of configuration changes within a time interval -- for mean-field and one-dimensional Ising models, in the presence of a magnetic field. We identify several dynamical phase transitions that appear as singularities in the scaled cumulant generating function of the activity. In particular, we find low-activity ferromagnetic states and a novel high-activity phase, with associated first- and second-order phase transitions. The high-activity phase has a negative susceptibility to the magnetic field. In the mean-field case, we analyse the dynamical phase coexistence that occurs on first-order transition lines, including the optimal-control forces that reproduce the relevant large deviations. In the one-dimensional model, we use exact diagonalisation and cloning methods to perform finite-size scaling of the first-order phase transition at non-zero magnetic field.
