Tunable nanomagnetism in moderately cold fermions on optical lattices

Abstract

Localized defects, unavoidable in real solids, may be simulated in (generically defect-free) cold-atom systems, e.g., via modifications of the optical lattice. We study the Hubbard model on a square lattice with single impurities, pairs of nearby impurities, or lines of impurities using numerically exact determinantal quantum Monte Carlo simulations. In all cases, correlations on the "impurity" sites are enhanced either by larger on-site interactions or by a reduced coupling to the environment. We find highly nontrivial magnetic correlations, which persist at elevated temperatures and should be accessible in cold-atom systems with current experimental techniques. With improved cooling techniques, these features could be followed towards generic quantum antiferromagnetism in the homogeneous limit. More generally, tunable crossing points between different correlation functions could be used, in a quantum steelyard balance setup, as robust thermometers.

8 pages, 7 figures, version accepted for publication by Phys. Rev. A

References in corpus (17)

• Single-Spin Addressing in an Atomic Mott Insulator
• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
• A trapped single ion inside a Bose-Einstein condensate
• Anderson localization in Bose-Einstein condensates
• Strongly interacting bosons in a disordered optical lattice
• Antiferromagnetic Order of Strongly Interacting Fermions in a Trap: Real-Space Dynamical Mean-Field Analysis
• Mott transition of fermionic atoms in a three-dimensional optical trap
• Controlling and Detecting Spin Correlations of Ultracold Atoms in Optical lattices
• Probing nearest-neighbor correlations of ultracold fermions in an optical lattice
• Néel transition of lattice fermions in a harmonic trap: a real-space DMFT study
• Momentum-dependent pseudogaps in the half-filled two-dimensional Hubbard model
• Single Impurity In Ultracold Fermi Superfluids
• Bound states of a localized magnetic impurity in a superfluid of paired ultracold fermions
• Anderson impurity in the one-dimensional Hubbard model on finite size systems
• Mott transitions in the half-filled SU(2M) symmetric Hubbard model
• Self-localization of a small number of Bose particles in a superfluid Fermi system
• Quantum Monte Carlo simulations of antiferromagnetism in ultracold fermions on optical lattices within real-space dynamical mean-field theory