Spin liquid and Deconfined Criticality in a Kagome Lattice Bose-Hubbard Model

          @misc{ pirsa_PIRSA:12050039,
            doi = {10.48660/12050039},
            url = {https://pirsa.org/12050039},
            author = {Melko, Roger},
            keywords = {},
            language = {en},
            title = {Spin liquid and Deconfined Criticality in a Kagome Lattice Bose-Hubbard Model},
            publisher = {Perimeter Institute},
            year = {2012},
            month = {may},
            note = {PIRSA:12050039 see, \url{https://pirsa.org}}
          }
          

Abstract

We present large-scale quantum Monte Carlo simulations on a sign-problem free Bose-Hubbard model on the kagome lattice. This model supports a quantum Z2 spin liquid phase with fractional excitations and topological order, which can be characterized definitively through calculation of the topological entanglement entropy.  I will outline how the entanglement entropy can be measured in general using a direct implementation of the "replica trick", which allows for the study of entanglement scaling in a variety of other models amenable to study by QMC.  Finally, I will examine the kagome model's superfluid/spin-liquid transition, which is an example of an exotic deconfined quantum critical point called XY*, mediated by the fractional charges.  This fact is demonstrated in several universal quantities that we measure, and may also be reflected the scaling of entanglement entropy at the critical point.