Studying the low-entropy Mott transition of bosons in a three-dimensional optical lattice by measuring the full momentum-space density

Abstract

We report on a combined experimental and theoretical study of the low-entropy Mott transition for interacting bosons trapped in a three-dimensional (3D) cubic lattice -- namely, the interaction-induced superfluid-to-normal phase transition in the vicinity of the zero-temperature Mott transition. Our analysis relies on the measurement of the 3D momentum distribution, which allows us to extract the momentum-space density $\rho (\mathbf{k}=0)$ at the center of the Brillouin zone. Upon varying the ratio between the interaction $U$ and the tunnelling energy $J$ across the superfluid transition, we observe that $\rho (\mathbf{k}=0)$ exhibits a sharp transition at a value of $U/J$ consistent with the bulk prediction from quantum Monte Carlo. In addition, the variation of $\rho (\mathbf{k}=0)$ with $U/J$ exhibits a critical behavior consistent with the expected 3D XY universality class. Our results show that the tomographic reconstruction of the momentum distribution of ultracold bosons can reveal traits of the critical behavior of the superfluid transition even in an inhomogeneous trapped system.

5 pages, 4 figures

References in corpus (7)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Emergence of coherence and the dynamics of quantum phase transitions
• Measurement of the Homogeneous Contact of a Unitary Fermi gas
• Phase diagram for a Bose-Einstein condensate moving in an optical lattice
• Phases of a 2D Bose Gas in an Optical Lattice
• Certifying the adiabatic preparation of ultracold lattice bosons in the vicinity of the Mott transition
• Two-body collisions in the time-of-flight dynamics of lattice Bose superfluids

Cited by in corpus (5)

• Suppression of Bogoliubov momentum pairing and emergence of non-Gaussian correlations in ultracold interacting Bose gases
• Production of a highly degenerate Fermi gas of metastable helium-3 atoms
• Strong-coupling RPA theory of a Bose gas near the superfluid--Mott-insulator transition: universal thermodynamics and two-body contact
• Measurement of the $s$-wave scattering length between metastable helium isotopes
• Observation of universal non-Gaussian statistics of the order parameter across a continuous phase transition