Experimental observation of the Yang-Lee quantum criticality in open systems

Abstract

The Yang-Lee edge singularity was originally studied from the standpoint of mathematical foundations of phase transitions, and its physical demonstration has been of active interest both theoretically and experimentally. However, the presence of an imaginary magnetic field in the Yang-Lee edge singularity has made it challenging to develop a direct observation of the anomalous scaling with negative scaling dimension associated with this critical phenomenon. We experimentally implement an imaginary magnetic field and demonstrate the Yang-Lee edge singularity through a nonunitary evolution governed by a non-Hermitian Hamiltonian in an open quantum system, where a classical system is mapped to a quantum system via the equivalent canonical partition function. In particular, we directly observe the partition function in our experiment using heralded single photons. The nonunitary quantum criticality is identified with the singularity at an exceptional point. We also demonstrate unconventional scaling laws for the finite-temperature dynamics unique to quantum systems.

11 pages, 9 figures

References in corpus (6)

• The physics of exceptional points
• Observation of Lee-Yang zeros
• Thermodynamics of pairing in mesoscopic systems
• Kibble-Zurek scaling in the Yang-Lee edge singularity
• Two-time correlation functions and the Lee-Yang zeros for an interacting Bose gas
• Lee-Yang theory of criticality in interacting quantum many-body systems

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• Dynamical signatures of the Yang-Lee edge singularity in non-Hermitian systems
• Topological phase transition in fluctuating imaginary gauge fields
• Lee-Yang theory of the superradiant phase transition in the open Dicke model
• Imaginary-Temperature Zeros for Quantum Phase Transitions
• Yang-Lee edge singularity and quantum criticality in non-Hermitian PXP model
• Non-equilibrium dynamics of localization phase transition in the non-Hermitian Disorder-Aubry-André model
• Lee-Yang formalism for phase transitions of interacting fermions using tensor networks
• Characterizing the Yang-Lee zeros of the classical Ising model through dynamic quantum phase transitions
• Mechanical cosmology: simulating scalar fluctuations in expanding Universes using synthetic mechanical lattices
• Fidelity zeros and Lee-Yang theory of quantum phase transitions
• Yang-Lee Zeros of 2D Nearest-Neighbor Antiferromagnetic Ising Models: A Numerical Linked Cluster Expansion Study
• Dissipation induced ergodic-nonergodic transitions in finite-height mosaic Wannier-Stark lattices