Entanglement in finite and semi-infinite free Fermionic chains is studied. A parallel is drawn with the analysis of time and band limiting in signal processing. It is shown that a tridiagonal matrix commuting with the entanglement Hamiltonian can be found using the algebraic Heun operator construct in instances when there is an underlying bispectral problem. Cases corresponding to the Lie algebras 𝔰𝔲(2) and 𝔰𝔲(1, 1) as well as to the q-deformed algebra 𝔰𝔬q(3) at q a root of unity are presented.

中文翻译：

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费米子链和双谱中的纠缠

研究了有限和半无限自由费米子链中的纠缠。与信号处理中的时间和频带限制分析相类似。结果表明，在存在潜在双谱问题的情况下，可以使用代数 Heun 算子构造找到与纠缠哈密顿量交换的三对角矩阵。对应于李代数的情况𝔰𝔲(2)和𝔰𝔲(1, 1)以及 q 变形代数𝔰𝔬q(3)在q提出了统一的根源。