Quantum simulation of SU(4) symmetric spin lattice models

 

Quantum spin-orbital liquids are strongly correlated states that emerge from quantum frustration between spin and orbital degrees of freedom. Those states are highly entangled, have non-local excitations but do not break any symmetries. A promising route towards observing those elusive states is the creation of artificial Mott insulators, where antiferromagnetic correlations between spins and orbitals can be designed. I will show that Coulomb impurity lattices on the surface of gapped honeycomb substrates, such as graphene on SiC, can be used to simulate SU(4) symmetric spin-orbital lattice models in the Mott regime [1]. The antiferromagnetic correlations follow from super-exchange interactions between Coulomb impurity bound states at quarter filling, with spin and valley degeneracies. I propose that quantum spin-orbital liquids can be engineered in artificially designed solid-state systems at vastly higher temperatures than achievable in optical lattices with cold atoms. At the end of my talk, I will briefly discuss other  systems with topological domain walls that could be used to simulate spin lattice models with SU(4) symmetry. In the ferromagnetic regime of those systems, I will discuss the possibility of a novel anomalous Hall effect [2].

[1] X. Dou, V. N. Kotov and B. Uchoa,  Sci. Rep. 6, 31737 (2016).
[2] B. Uchoa, V. N. Kotov,  and M. Kindermann, Phys. Rev. B (R) 91, 121412 (2015).