2020/05/31 by Qi Zhang, Wen-Tao Xu, Zi-Qi Wang +1
Physics and Astronomy · #Amplitude #Conformal field theory #Conformal map #Connection (principal bundle) #Lattice (music) #Partition function (quantum field theory) #Phase (matter) #Quantum #Quantum Mechanics and Non-Hermitian Physics #Quantum many-body systems #Statistical Mechanics and Entropy #Wave function #cond-mat.stat-mech #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1038/s42005-020-00479-y
published as Commun Phys 3, 209 (2020) · 19 pages, 8 figures; revised manuscript includes some additional results
openalex created_date 2020/05/13 · arxiv created 2020/07/07 · openalex publication_date 2020/11/13 · arxiv updated 2020/11/23 · openalex updated_date 2026/08/05
Abstract Negative signs in many-body wavefunctions play an important role in quantum mechanics because interference relies on cancellation between amplitudes of opposite signs. The ground-state wavefunction of double semion model contains negative signs that cannot be removed by any local transformation. Here we study the quantum effects of these intrinsic negative signs. By proposing a generic double semion wavefunction in tensor network representation, we show that its norm can be mapped to the partition function of a triangular lattice Ashkin-Teller model with imaginary interactions. We use numerical tensor-network methods to solve this non-Hermitian model with parity-time symmetry and determine a global phase diagram. In particular, we find a dense loop phase described by non-unitary conformal field theory and a parity-time-symmetry breaking phase characterized by the zeros of the partition function. Therefore, our work establishes a connection between the intrinsic signs in the topological wavefunction and non-unitary phases in the parity-time-symmetric non-Hermitian statistical model.