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Center for Nonlinear Studies |
Due to the interplay of orbital anisotropy and lattice geometry, Optical cold atoms in higher orbital states provide a new playground for investigating strongly frustrated systems. A canonical example of geometrical frustration is proton ordering in water ice. Magnetic analog of ice was also found in rare-earth pyrochlore oxides known as spin ice. In both cases, there exists an emergent Coulomb phase which is characterized by algebraic dipolar-like correlations and a gauge structure resulting from the local constraints (ice rules) of the underlying lattice models. Here we demonstrate the existence of orbital Coulomb phase as the exact many-body ground state of p-orbital exchange Hamiltonian on the diamond lattice. Contrary to other ice models, the orbital ice rules are emergent phenomena resulting from the quantum orbital dynamics. We compute the orbital correlations in the Coulomb phase by exploiting an one-to-one mapping between the orbital-ice states and the spin-ice states obeying the 2-in-2-out constraints on the pyrochlore lattice.
Host: Kipton Barros, T-4 and CNLS