We study spreading wave packets in a disordered nonlinear ladder with brokentime-reversal symmetry induced by synthetic gauge fields. The model describesthe dynamics of interacting bosons in a disordered and driven optical ladderwithin a mean-field approximation. The second moment of the wave packet $m_{2}= g t^{\alpha}$ grows subdiffusively with the universal exponent $\alpha \simeq1/3$ similar to the time-reversal case. However the prefactor $g$ is stronglymodified by the field strength and shows a non-monotonic dependence. For a weakfield, the prefactor increases since time-reversal enhanced backscattering issuppressed. For strong fields the spectrum of the linear wave equation reducesthe localization length through the formation of gaps and narrow bands.Consequently the prefactor for the subdiffusive spreading law is suppressed.
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机译：我们研究了由合成规范场引起的具有破坏时间反转对称性的无序非线性阶梯中的扩展波包。该模型在平均场近似范围内描述了无序和驱动光梯中相互作用的玻色子的动力学。波包$ m_ {2} = g t ^ {\ alpha} $的第二阶矩与时间反转情况相似，其通用指数$ \ alpha \ simeq1 / 3 $次扩散。但是，前置因子$ g $被场强强烈修改，并显示出非单调依赖性。对于弱场，由于抑制了时间反向增强的反向散射，因此前置因子增加。对于强场，线性波动方程的频谱通过形成间隙和窄带来减小定位长度，从而抑制了亚扩散扩散定律的前因。
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