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

The observation of entanglement phase transitions in many-body systems subject to competition between unitary and non-unitary dynamics faces the fundamental barrier of post-selection problem. In this work, we sidestep this issue by considering only fully unitary dynamics. Despite its fully unitary dynamics, the 1D bosonic Kitaev chain (BKC) displays key hallmarks of non-Hermitian physics traditionally associated with non-unitarity, such as non-reciprocal transport and the non-Hermitian skin effect. Here we demonstrate [1] another remarkable phenomena: despite not having any disorder, a variant of the BKC model exhibits an entanglement phase transition (EPT) as a function of a Hamiltonian parameter g. The transition is between regimes of volume law to “super-volume law” post-quench entanglement growth, and coincides with a transition from a reciprocal to a non-reciprocal phase.

[1] G. Lee, T. Jin, Y.-X. Wang, A. McDonald, and A. A. Clerk. arXiv:2308.14614