Physics @ Berkeley
Events in Physics
Title: 290K Condensed Matter Seminar    (Seminar)
Start Date: 01/30/2006
Time: 2:30 pm
Location: 2 LeConte Hall
Speaker: Patrick Lee
Affiliation: MIT
Contact Person: Frances Hellman   (510) 642-6135
Details: For a number of years there has been intensive search for an experimental system which exhibits the spin liquid state, or a reasonably simple Hamiltonian which supports a fractionalized ground state. There has been promising recent developments on both fronts. I shall review some experimental data on the organic compound kappa-(ET)_2Cu_2(CN)_3 and the theory which suggests that a spin liquid state may be stable near the metal-insulator transition in the Hubbard model on a triangular lattice. I shall also describe a model of exciton condensation with orbital degeneracies which exhibits fractionalization. In this model the fractionalized particle and the emergent gauge field can be visualized physically in a world line picture. Furthermore, the model can be simulated by quantum Monte Carlo without sign problems.