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arXiv · 2210.11937

Volume-to-Area Law Entanglement Transition in a non-Hermitian Free Fermionic Chain

Youenn Le Gal·Xhek Turkeshi·Marco Schirò
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Abstract

We consider the dynamics of the non-Hermitian Su-Schrieffer-Heeger model arising as the no-click limit of a continuously monitored free fermion chain where particles and holes are measured on two sublattices. The model has $\mathcal{PT}$-symmetry, which we show to spontaneously break as a function of the strength of measurement backaction, resulting in a spectral transition where quasiparticles acquire a finite lifetime in patches of the Brillouin zone. We compute the entanglement entropy's dynamics in the thermodynamic limit and demonstrate an entanglement transition between volume-law and area-law scaling, which we characterize analytically. Interestingly we show that the entanglement transition and the $\mathcal{PT}$-symmetry breaking do not coincide, the former occurring when the entire decay spectrum of the quasiparticle becomes gapped.

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Youenn Le Gal, Xhek Turkeshi, Marco Schirò. 2023-02-22. Volume-to-Area Law Entanglement Transition in a non-Hermitian Free Fermionic Chain. https://doi.org/10.21468/scipostphys.14.5.138

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