Competing Valence Bond States of Spin-3/2 Fermions on a Strongly Coupled Ladder

TL;DR

This paper investigates the ground states of strongly coupled spin-3/2 fermionic ladders, revealing competing valence bond states, a Luttinger liquid phase, and a topological Haldane state depending on system parameters.

Contribution

It introduces a mapping of the ladder system to an effective one-band model and identifies novel ground states, including topologically nontrivial phases, in this context.

Findings

Luttinger liquid is the ground state in a broad parameter region.

Topological Haldane state appears at quarter and three-quarter fillings.

Various valence bond and plaquette states compete based on filling and interaction ratios.

Abstract

We study the possible ground state configurations of two strongly coupled chains of charge neutral spin-3/2 fermionic atoms interacting via short range van der Waals interaction. The coupling between the two chains is realized by relatively large hopping amplitude. Exploiting that such a ladder configuration can be mapped to an effective one-band model we analyze the emerging ground states of the system. We show that various spatially inhomogeneous states, valence bond states, plaquette states compete depending on the filling and the ratio of the interaction strengths in the singlet and quintet scattering channel. We find that a Luttinger liquid state is the ground state of the strongly coupled ladder in an extended region of the parameter space, and we also show that a topologically nontrivial charge Haldane state can emerge in the strongly coupled ladder at quarter and three-quarter fillings.