Doping a 2d Mott insulator – Study of a quantum dimer model*

Experiments with quantum gas microscopes have started to explore the antiferromagnetic phase of the Fermi-Hubbard model and effects of doping with holes away from half filling¹. We show in this talk that the system averaged local two-spin density matrix enables to distinguish magnetically ordered and interesting topologically ordered spin-liquid phases, which might occur in the Hubbard model close to half filling.
Fractionalized Fermi liquids (FL*) are a promising candidate for this parameter regime. The generalized quantum dimer model introduced in Ref. [2] is an effective lattice realization of such an FL* with a Hilbert space spanned by configurations of fermionic and bosonic short-range bound states. We construct a rather unconventional dynamical cluster approximation (DCA) by making explicit use of the dimer Hilbert space and show first results of spectral data for a minimal cluster of two lattice sites.

¹A. Mazurenko, C. Chiu et al., Nature 545, 7655 (2017)
²M. Punk, A. Allais and S. Sachdev, PNAS 112, 31 (2015)