Thermal Entropy, Density Disorder and Antiferromagnetism of Repulsive Fermions in 3D Optical Lattice

Abstract

The celebrated antiferromagnetic (AFM) phase transition was realized in a most recent optical lattice experiment for the 3D fermionic Hubbard model [Shao {\it et al}., Nature {\bf 632}, 267 (2024)]. Despite this important progress, it was observed that the AFM structure factor (and also the critical entropy) reaches the maximum at an interaction strength $U/t\simeq 11.75$, which is significantly larger than the theoretical prediction of $U/t\simeq 8$. Here, we resolve this discrepancy by studying the interplay between the thermal entropy, density disorder, and antiferromagnetism in the half-filled 3D Hubbard model, using numerically exact auxiliary-field quantum Monte Carlo simulations. We have achieved an accurate entropy phase diagram, enabling us to simulate arbitrary entropy path on the temperature-interaction plane and track experimental parameters effectively. We find that above discrepancy can be quantitatively explained by the {\it entropy increase} associated with increasing interaction strength in experiment, and together by the lattice {\it density disorder} present in the experimental setup. We further investigate the entropy dependence of double occupancy and predict universal behaviors that could serve as valuable probes in future optical lattice experiments.

8 pages, 6 figures

References in corpus (13)

• Many-Body Physics with Ultracold Gases
• Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond
• The Hubbard Model
• Tools for quantum simulation with ultracold atoms in optical lattices
• Observation of antiferromagnetic correlations in the Hubbard model with ultracold atoms
• Coexistence of superconductivity with partially filled stripes in the Hubbard model
• Frustration- and doping-induced magnetism in a Fermi-Hubbard simulator
• Interaction-Induced Adiabatic Cooling for Antiferromagnetism in Optical Lattices
• Temperature Dependence of Spin and Charge Orders in the Doped Two-Dimensional Hubbard Model
• Thermodynamics and magnetism in the 2D-3D crossover of the Hubbard model
• Magnetic, thermodynamic, and dynamical properties of the three-dimensional fermionic Hubbard model: A comprehensive Monte Carlo study
• Extended Metal-Insulator Crossover with Strong Antiferromagnetic Spin Correlation in Half-Filled 3D Hubbard Model
• Magnetic phase diagram of the three-dimensional doped Hubbard model

Cited by in corpus (1)

• Quantum Monte Carlo study of the metal-insulator crossover in the square-lattice Hubbard model