Speaker
Description
The characterization of non-unitary conformal field theories (CFTs) via entanglement measures is often hindered by the appearance of negative central charges, which lack a clear interpretation in standard entanglement theory. We address this by formulating a generalized entanglement entropy that remains well-defined in the non-unitary regime. Through numerical and analytical validation—including applications to the PT-symmetric Su-Schrieffer-Heeger model and quantum-group-invariant XXZ chains—we show that this measure accurately captures the scaling of non-unitary CFTs. We further apply this framework to investigate non-Hermitian critical phenomena. Our results reveal that local non-Hermitian perturbations can induce exceptional points that significantly alter the system's criticality, specifically shifting the central charge from c=1 to c=−2. Additionally, we present a novel PT-symmetric gapless SPT phase characterized by the presence of boundary modes that exhibit an unconventional degree of robustness, suggesting new directions for the study of topology in non-Hermitian critical systems.