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arXiv · 2308.14614

Entanglement phase transition due to reciprocity breaking without measurement or post-selection

Gideon Lee·Tony Jin·Yu-Xin Wang·Alexander McDonald·Aashish Clerk
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Abstract

Despite its fully unitary dynamics, the bosonic Kitaev chain (BKC) displays key hallmarks of non-Hermitian physics including non-reciprocal transport and the non-Hermitian skin effect. Here we demonstrate another remarkable phenomena: the existence of an entanglement phase transition (EPT) in a variant of the BKC that occurs as a function of a Hamiltonian parameter g, and which coincides with a transition from a reciprocal to a non-reciprocal phase. As g is reduced below a critical value, the post-quench entanglement entropy of a subsystem of size l goes from a volume-law phase where it scales as l to a super-volume law phase where it scales like lN with N the total system size. This EPT occurs for a system undergoing purely unitary evolution and does not involve measurements, post-selection, disorder or dissipation. We derive analytically the entanglement entropy out of and at the critical point for the $l=1$ and $l/N \ll 1$ case.

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Gideon Lee, Tony Jin, Yu-Xin Wang, Alexander McDonald, Aashish Clerk. 2023-08-28. Entanglement phase transition due to reciprocity breaking without measurement or post-selection. https://doi.org/10.1103/prxquantum.5.010313

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