Probing Coherences and Itinerant Magnetism in a Dipolar Lattice Gas

TL;DR

This study investigates itinerant magnetism in a dipolar lattice gas of magnetic atoms, revealing phase-dependent magnetic behaviors and thermalization processes using advanced coherence measurement techniques.

Contribution

It introduces a novel experimental approach to probe magnetic phases and coherence in a dipolar lattice gas across a quantum phase transition.

Findings

Metastable ferromagnetism observed in the superfluid phase.

Thermalization towards paramagnetism driven by intersite and superexchange interactions.

Coherence measurements across the phase transition elucidate magnetic dynamics.

Abstract

We report on the study of itinerant magnetism of lattice-trapped magnetic atoms, driven by magnetic dipole-dipole interactions, in the low-entropy and close-to-unit filling regime. We have used advanced dynamical decoupling techniques to efficiently suppress the sensitivity to magnetic field fluctuations. We have thus measured the spin coherence of an itinerant spin 3 Bose dipolar gas throughout a quantum phase transition from a superfluid phase to a Mott insulating phase. In the superfluid phase, a metastable ferromagnetic behavior is observed below a dynamical instability which occurs at lattice depths below the phase transition. In the insulating phase, the thermalization towards a paramagnetic state is driven by an interplay between intersite and superexchange interactions.