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arXiv:2309.11670 · Physical review. B./Physical review. B

Non-Hermitian superfluid–Mott-insulator transition in the one-dimensional zigzag bosonic chains

Chengxi Li, Yu‐Biao Wu, Wu-Ming Liu

Published Jun 14, 2024• 6 citations
arXivHTMLPDF

Abstract

We investigated the behavior of non-Hermitian bosonic gases with Hubbard interactions in one-dimensional (1D) zigzag optical lattices through the calculation of dynamic response functions. Our findings showed the existence of a non-Hermitian quantum phase transition that is dependent on the pseudo-Hermitian symmetry. The system tends to exhibit a superfluid phase when subjected to weak dissipation. While under strong dissipation, the pseudo-Hermitian symmetry of the system is partially broken, leading to a transition toward a normal liquid phase. As the dissipation increases beyond the critical threshold, the pseudo-Hermitian symmetry is completely broken, resulting in a Mott-insulator phase. We propose an experimental setup using 1D zigzag optical lattices containing two-electron atoms to realize this system. In this paper, we emphasize the key role of non-Hermiticity in quantum phase transitions and offer a theoretical framework as well as experimental methods for understanding the behavior of dissipative quantum systems, implicating significant development of quantum devices and technologies.

DOI
10.1103/physrevb.109.214306

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In this paper, we investigate the quantum phases of two-component bosons in a non-Hermitian optical lattice system featuring a nonreciprocal hopping phase factor. Our analysis focuses on the Bose–Hubbard model in a two-dimensional (2D) square lattice, utilizing the inhomogeneous dynamical Gutzwiller mean-field theory (DGMFT) to examine the ground state. The impact on quantum phases of the inter component interaction varies in the weak-interaction (the inter-component interactions are smaller than intra-component interactions, i.e., [Formula: see text]) and in the strong-interaction (the inter-component interactions are bigger than intra-component interactions, i.e., [Formula: see text]) regime. In the weak regime, we observe a diverse range of quantum phases, including vortex-like liquid, MI islands (the Mott insulator (MI) islands periodically distributed in the superfluid (SF) background) and SF islands (the SF islands periodically distributed in the MI background), and the inter-component counterflow superfluid (CFSF) phases. In the strong regime, we observe phase separation of the two-component bosons.
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Abstract We explore the condensate phase of single-species bosons in an optical lattice through the use of dissipative Bose–Hubbard models. The ground state of system possesses a real-energy, which corresponds to non-Hermitian Hamiltonians with non-reciprocal hopping phase factors. Through the application of inhomogeneous dynamical Gutzwiller mean-field theory (DGMFT), we predict a fascinating phenomenon: the ground state displays a periodic arrangement of superfluid islands amidst a Mott insulator sea. Additionally, the number of superfluid islands is proportional to the spatial period squared.