aiqbench analysis
This research identifies a fundamental deviation in non-unitary quantum chains where entanglement entropy exhibits an interval-independent offset near exceptional points. By interpreting these phenomena through de Sitter geometry and holographic frameworks, the study reveals that residual entangled states persist even at single-site scales, challenging standard Calabrese-Cardy scaling laws found in Hermitian systems. These findings advance our theoretical understanding of non-Hermitian free fermions and how quantum criticality behaves under singular energy gaps.
Non-Unitary Chains Break Standard Entanglement Scaling

Criticality in non-unitary chains deviates from standard entanglement scaling, exhibiting a sensitivity to even a one-site energy gap.
Researchers have discovered that entanglement entropy in non-unitary critical chains behaves unexpectedly, revealing a sensitivity to energy gaps previously unseen in standard quantum systems. Kuang-Hung Chou of National Tsing Hua University demonstrated that these chains near exceptional points exhibit an interval-independent contribution to entanglement entropy, appearing as a vertical offset that defies typical scaling predictions. The entropy of an interval on a ring-shaped system takes a specific form, where data…
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