Phase diagram of the Bose Kondo-Hubbard model

Abstract

We study a bosonic version of the Kondo lattice model with an on-site repulsion in the conduction band, implemented with alkali atoms in two bands of an optical lattice. Using both weak and strong-coupling perturbation theory, we find that at unit filling of the conduction bosons the superfluid to Mott insulator transition should be accompanied by a magnetic transition from a ferromagnet (in the superfluid) to a paramagnet (in the Mott insulator). Furthermore, an analytic treatment of Gutzwiller mean-field theory reveals that quantum spin fluctuations induced by the Kondo exchange cause the otherwise continuous superfluid to Mott-insulator phase transition to be first order. We show that lattice separability imposes a serious constraint on proposals to exploit excited bands for quantum simulations, and discuss a way to overcome this constraint in the context of our model by using an experimentally realized non-separable lattice. A method to probe the first-order nature of the transition based on collapses and revivals of the matter-wave field is also discussed.

10 pages, 5 figures, V2: extended discussion of effective Hamiltonians and mean-field theory, added Fig. 3

References in corpus (9)

• Many-Body Physics with Ultracold Gases
• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Controlled exchange interaction between pairs of neutral atoms in an optical lattice
• A lattice of double wells for manipulating pairs of cold atoms
• Orbital superfluidity in the $P$-band of a bipartite optical square lattice
• State preparation and dynamics of ultracold atoms in higher lattice orbitals
• Orbital analogue of quantum anomalous Hall effect in $p$-band systems
• Incommensurate superfluidity of bosons in a double-well optical lattice
• Condensates induced by interband coupling in a double-well lattice

Cited by in corpus (13)

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• Quantum Rydberg Central Spin Model
• Variational principle for quantum impurity systems in and out of equilibrium: application to Kondo problems
• First order phase transitions in optical lattices with tunable three-body onsite interaction
• Confined p-band Bose-Einstein condensates
• Exotic phases of interacting p-band bosons
• Efficient variational approach to dynamics of a spatially extended bosonic Kondo model
• Finite temperature phase diagram of spin-1/2 bosons in two-dimensional optical lattice
• Bosonic Kondo-Hubbard model
• Mode folding in systems with local interaction: unitary and non-unitary transformations using tensor states
• Bosonic Peierls state emerging from the one-dimensional Ising-Kondo interaction