Lattice control of non-ergodicity in a polar lattice gas

TL;DR

This paper demonstrates how the non-ergodic behavior in a polar lattice gas can be controlled by tuning the effective power-law decay of inter-site interactions through experimental parameters, affecting particle dynamics.

Contribution

It reveals that the inter-site interaction in a 1D dipolar gas can be universally tailored, influencing Hilbert-space fragmentation and dynamics, which is experimentally controllable.

Findings

Interaction form depends on confinement and lattice depth.

Particle dynamics resemble a power-law model with tunable exponent.

Results are directly relevant for experimental setups with dipolar gases.

Abstract

Inter-site interactions in polar lattice gases may result, due to Hilbert-space fragmentation, in a lack of ergodicity even in absence of disorder. We show that the inter-site interaction in a one-dimensional dipolar gas in an optical lattice departs from the usually considered $1/r^3$ dependence, acquiring a universal form that depends on the transversal confinement and the lattice depth. Due to the crucial role played by the nearest- and next-to-nearest neighbors, the Hilbert-space fragmentation and particle dynamics are very similar to that of a power-law model $1/r^{\beta_{\mathrm{eff}}<3}$, where $\beta_{\mathrm{eff}}$ is experimentally controllable by properly tailoring the transversal confinement. Our results are of direct experimental relevance for experiments on dipolar gases in optical lattices, and show that the particle dynamics may be remarkably different if the quasi-1D lattice model is realized in a strong 3D lattice, or by means of a strong transversal harmonic confinement.