The bulk conductivity of a two-dimensional system is studied assuming that time-reversal symmetry is broken by internal mechanisms. The study is carried out by direct diagonalization in order to explore the nonlinear-response provoked by the inclusion of an electric field in the system’s Hamiltonian. The system displays a quantized conductivity that depends on the intensity of the field and under specific conditions the conductivity limit at zero electric field displays a nonvanishing value.

中文翻译：

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方格中的时间反转对称性破缺

假设时间反转对称性被内部机制破坏，研究二维系统的体电导率。该研究通过直接对角化进行，以探索系统哈密顿量中包含电场引起的非线性响应。该系统显示一个量化的电导率，该电导率取决于场强，并且在特定条件下，零电场下的电导率极限显示非零值。