| 研究実績の概要 |
We studied fermions with SU(N) internal degrees of freedom on the triangular lattice. .
We showed that, in the presence of a pi/2 artificial gauge field per plaquette, Mott insulating phases of fermions with SU(N) symmetry and one particle per site generically possess an extended chiral phase with intrinsic topological order characterized by a multiplet of N low-lying singlet excitations for periodic boundary conditions, and by chiral edge states described by the SU(N)_1 Wess-Zumino-Novikov-Witten conformal field theory for open boundary conditions. This has been achieved by extensive exact diagonalizations for N between 3 and 9, and by a parton construction based on a set of N Gutzwiller projected fermionic wave-functions with flux pi/N per triangular plaquette.
With the recent realization of the Mott-crossover regime in 3D optical lattices with fermionic Ytterbium atoms the prospect for the experimental realization of strongly correlated SU(N) quantum magnetism is becoming bright. Our proposal for triangular lattices builds on ingredients which have been demonstrated separately: the possibility to realize Mott insulators in optical lattices, and to create static artificial gauge fields in an optical lattice (for alkaline atoms). Besides, working with the triangular lattice is a big advantage because the 3-site permutation term is the first and only term to appear to third order perturbation theory starting from the Hubbard model with one particle per site, by contrast to e.g. the square and honeycomb lattice, where they appear at order 4 and 6 respectively.
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