Certifying the adiabatic preparation of ultracold lattice bosons in the vicinity of the Mott transition

TL;DR

This paper combines experimental measurements and quantum Monte Carlo simulations to verify that ultracold bosons in optical lattices can be prepared in equilibrium states near the Mott transition, demonstrating adiabatic control in quantum simulations.

Contribution

It provides a validated thermometry method and confirms the adiabatic preparation of equilibrium states near the Mott transition in cold-atom experiments.

Findings

Measured temperatures match QMC predictions across the transition.

Thermometry is most accurate near the critical regime.

Equilibrium states including quantum-critical regimes can be prepared adiabatically.

Abstract

We present a joint experimental and theoretical analysis to assess the adiabatic experimental preparation of ultracold bosons in optical lattices aimed at simulating the three-dimensional Bose-Hubbard model. Thermometry of lattice gases is realized from the superfluid to the Mott regime by combining the measurement of three-dimensional momentum-space densities with ab-initio quantum Monte Carlo (QMC) calculations of the same quantity. The measured temperatures across the superfluid-to-Mott transition are in agreement with isentropic lines reconstructed via QMC for the experimental parameters of interest, with a conserved entropy per particle of $S/N=0.8(1) k_{B}$. In addition, the Fisher information associated with this thermometry method shows that the latter is most accurate in the critical regime close to the Mott transition, as confirmed in the experiment. These results prove that equilibrium states of the Bose-Hubbard model - including those in the quantum-critical regime above the Mott transition - can be adiabatically prepared in cold-atom apparatus.