Quantum-granularity effect in the formation of supermixed solitons in ring lattices

TL;DR

This paper explores the quantum-granularity effect in bosonic binary mixtures in ring lattices, revealing staircase-like phase structures and supermixed solitons through quantum analysis and analytical approximation.

Contribution

It introduces the concept of quantum-granularity effects leading to supermixed solitons in ring lattice systems, combining quantum indicators and analytical models.

Findings

Identification of staircase-like phase diagram structures.

Demonstration of jerky interwell boson transfer at small hopping amplitudes.

Interpretation of interspecies attraction as an effective chemical potential.

Abstract

We investigate a notable class of states peculiar to a bosonic binary mixture featuring repulsive intraspecies and attractive interspecies couplings. We evidence that, for small values of the hopping amplitudes, one can access particular regimes marked by the fact that the interwell boson transfer occurs in a jerky fashion. This property is shown to be responsible for the emergence of a staircase-like structure in the phase diagram of a mixture confined in a ring trimer and to strongly resemble the mechanism of the superfluid-Mott insulator transition. Under certain conditions, in fact, we show that it is possible to interpret the interspecies attraction as an effective chemical potential and the supermixed soliton as an effective particle reservoir. Our investigation is developed both within a fully quantum approach based on the analysis of several quantum indicators and by means of a simple analytical approximation scheme capable of capturing the essential features of this ultraquantum effect.