In this work, we investigate many-body phase transitions in a one-dimensional anisotropic XY model subject to a complex-valued transverse field. Within the biorthogonal framework, we calculate the ground-state correlation functions and entanglement entropy, confirming that their scaling behavior remains identical to that in the Hermitian XY model. The preservation of Hermitian phase transition features in the non-Hermitian setting is rooted in the persistence and emergence of symmetries and their breaking. Specifically, the ferromagnetic (FM) phase arises from the breaking of a $Z_2$ symmetry, while the Luttinger liquid (LL) phase is enabled by the emergence of a $\text{U}\left(1\right)$ symmetry together with the degeneracy of the real part of the energy spectrum. The nontrivial topology of the LL phase is characterized by the winding number around the exceptional point (EP). Given that non-Hermitian systems are inherently open, our findings suggest a new avenue for exploring universal critical phenomena associated with conventional quantum phase transitions, which are typically vulnerable to decoherence and environmental disruption in conventional open quantum systems.

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• Quantum criticality
• Quantum phase transitions
• Topological order
• Topological phase transition
• 1-dimensional spin chains
• Exceptional points
• Non-Hermitian systems
• Quantum many-body systems
• Symmetries in condensed matter
• XY model