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arXiv · 2101.06032

The phases of the disordered Bose-Hubbard model with attractive interactions

Olli Mansikkamäki·Sami Laine·Matti Silveri
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Abstract

We study the quantum ground state phases of the one-dimensional disordered Bose--Hubbard model with attractive interactions, realized by a chain of superconducting transmon qubits or cold atoms. We map the phase diagram using perturbation theory and exact diagonalization. Compared to the repulsive Bose--Hubbard model, the quantum ground state behavior is dramatically different. At strong disorder of the on-site energies, all the bosons localize into the vicinity of a single site, contrary to the Bose glass behavior of the repulsive model. At weak disorder, depending on hopping, the ground state is either superfluid or a W state, which is a multi-site and multi-particle entangled superposition of states where all the bosons occupy a single site. We show that the robustness of the W phase against disorder diminishes as the total number of bosons increases.

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Olli Mansikkamäki, Sami Laine, Matti Silveri. 2021-01-15. The phases of the disordered Bose-Hubbard model with attractive interactions. https://doi.org/10.1103/physrevb.103.l220202

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