发表机构
School of Physics, Beihang University; Graduate School of China Academy of Engineering Physics（北京航空航天大学物理学院; 中国工程物理研究院研究生部）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究针对有限键维度PEPS难以描述二维带隙手性相的问题，提出辅助系统辅助的PEPS框架，成功恢复手性拓扑信息，为获取带隙手性相提供实用途径。
AI 中文摘要
无限投影纠缠对态（PEPS）能否忠实地描述二维中的带隙手性相一直存在争议。有限键维度的PEPS能够捕捉手性相的诸多局域和拓扑性质，但通常会产生虚假的长程幂律型关联。我们引入一种辅助系统辅助的框架，通过将物理手性系统与一个时间反演的辅助伙伴系统嵌入在一起，规避这一障碍，得到一个非手性的扩展表示，其中物理手性子系统可通过可控退耦恢复。对于自由费米子陈绝缘体和相互作用手性自旋液体，所得PEPS显示出清晰的带隙关联函数，以及有限的转移矩阵关联长度，这与直接手性PEPS表示的人工长程尾形成对比。由于有限纠缠效应，物理系统与辅助系统之间存在微小且可忽略的耦合，仅影响短程局域量。尽管是非手性的扩展表示，手性拓扑信息仍编码在纠缠中。利用层分辨动量投影，我们恢复了预期的普适手性纠缠边界谱。本研究为利用有限键维度PEPS获取带隙手性相提供了一条实用途径，该途径通过改变表示问题而非直接研究手性纯态来实现。
英文摘要
Gapped chiral phases pose an intrinsic obstruction to projected entangled pair state (PEPS) representations with finite bond dimension $D$, which generically develop spurious long-range correlations despite the gapped nature of the target state. To address this long-standing problem, we take a qualitatively different route by considering the target chiral system together with a completely decoupled time-reversed auxiliary copy. Constraining the finite-$D$ PEPS to the factorized form would simply reduce the problem to representing each chiral layer independently, leaving the original finite-$D$ obstruction unchanged. Unexpectedly, however, we find that finite-$D$ variational optimization generates an \emph{emergent} residual interlayer entanglement, despite the absence of any explicit interlayer coupling in the Hamiltonian. This emergent entanglement is the key mechanism that bypasses the obstruction, qualitatively changing the PEPS from an effectively gapless representation with long-range correlation tails to one with a finite correlation length. We demonstrate this mechanism for both a free-fermion Chern insulator and an interacting chiral spin liquid. The residual entanglement is systematically suppressed with increasing $D$, approaching the decoupled limit, while the chiral topological information remains accessible through layer-resolved entanglement spectra. Our results thus uncover a previously unrecognized mechanism for bypassing the chiral obstruction through variationally generated auxiliary entanglement.
