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arXiv · 1906.06246

Kagome model for a ${\mathbb Z}_2$ quantum spin liquid

Matthew S. Block·Jonathan D'Emidio·Ribhu K. Kaul
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Abstract

We present a study of a simple model antiferromagnet consisting of a sum of nearest neighbor SO($N$) singlet projectors on the Kagome lattice. Our model shares some features with the popular $S=1/2$ Kagome antiferromagnet but is specifically designed to be free of the sign-problem of quantum Monte Carlo. In our numerical analysis, we find as a function of $N$ a quadrupolar magnetic state and a wide range of a quantum spin liquid. A solvable large-$N$ generalization suggests that the quantum spin liquid in our original model is a gapped ${\mathbb Z}_2$ topological phase. Supporting this assertion, a numerical study of the entanglement entropy in the sign free model shows a quantized topological contribution.

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Matthew S. Block, Jonathan D'Emidio, Ribhu K. Kaul. 2019-06-14. Kagome model for a ${\mathbb Z}_2$ quantum spin liquid. https://doi.org/10.1103/physrevb.101.020402

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