AI 中文总结
研究临界非厄米自由费米子链稳态纠缠熵，发现其对数标度系数反常，源于‘虚’狄拉克点处本征向量非正交性，低能展开得系数与晶格数值吻合，弱实在位无序增强纠缠，提供了对该稳态纠缠的通用理解。
AI 中文摘要
纠缠承载着标记相和临界点的通用内容。我们研究临界非厄米自由费米子链稳态的纠缠熵。它随子系统大小对数标度，但系数随参数连续变化并形成一个雷尼族，没有单个中心电荷能重现。我们将这种反常追溯到一个‘虚’狄拉克点，即能量虚部的一个交叉点，占据态在两个布洛赫态之间切换。它们的非正交性削弱了占据不连续性并降低了对数系数。低能展开得到的封闭形式系数与各种一维临界稳态的晶格数值非常吻合。值得注意的是，弱实在位无序使这种对数标度保持不变并增强了纠缠。我们的结果为临界非厄米自由费米子稳态中的纠缠提供了一般性理解。
英文摘要
Entanglement carries universal content that labels phases and critical points. We study the entanglement entropy of the steady states of critical non-Hermitian free-fermion chains. It scales logarithmically with subsystem size, but the coefficients vary continuously with the parameters and form a Rényi family that no single central charge can reproduce. We trace this anomaly to an ``imaginary'' Dirac point, a crossing in the imaginary part of the energy where the occupied state switches between two Bloch states. Their nonorthogonality weakens the occupation discontinuity and lowers the logarithmic coefficient. A low-energy expansion yields closed-form coefficients in excellent agreement with lattice numerics in various one-dimensional critical steady states. Remarkably, weak real onsite disorder leaves this logarithmic scaling intact and enhances the entanglement. Our results provide a generic understanding of entanglement in critical non-Hermitian free-fermion steady states.
