Superexchange Liquefaction of Strongly Correlated Lattice Dipolar Bosons

TL;DR

This paper introduces a novel mechanism for liquid formation in strongly correlated lattice systems, specifically dipolar bosons, highlighting superexchange processes and their experimental signatures.

Contribution

It presents a perturbative theory validated by DMRG simulations, revealing a new quantum liquid phase driven by superexchange in dipolar bosons.

Findings

Identification of a superexchange-driven quantum liquid phase

Distinct dynamic structure factor signatures in different phases

Nontrivial behavior of the speed of sound due to broken Galilean invariance

Abstract

We propose a mechanism for liquid formation in strongly correlated lattice systems. The mechanism is based on an interplay between long-range attraction and superexchange processes. As an example, we study dipolar bosons in one-dimensional optical lattices. We present a perturbative theory and validate it in comparison with full density-matrix renormalization group simulations for the energetic and structural properties of different phases of the system, i.e., self-bound Mott insulator, liquid, and gas. We analyze the nonequilibrium properties and calculate the dynamic structure factor. Its structure differs in compressible and insulating phases. In particular, the low-energy excitations in compressible phases are linear phonons. We extract the speed of sound and analyze its dependence on dipolar interaction and density. We show that it exhibits a nontrivial behaviour owing to the breaking of Galilean invariance. We argue that an experimental detection of this previously unknown quantum liquid could provide a fingerprint of the superexchange process and open intriguing possibilities for investigating non-Galilean invariant liquids.