he Haldane conjecture and show that the O(3) nonlinear sigma model with a \theta term in two dimensions becomes massless at \theta=\pi= 3:10(5). A modified cluster algorithm has been introduced to simulate the model with imaginary \theta. Two different definitions of the topological charge on the lattice have been used; one of them needs renormalization to match the continuum operator. Our work also offers a successful test for numerical methods based on analytic continuation.
Mass gap in the 2D O(3) non--linear sigma model with a theta=pi term
PAPA, Alessandro
2008-01-01
Abstract
he Haldane conjecture and show that the O(3) nonlinear sigma model with a \theta term in two dimensions becomes massless at \theta=\pi= 3:10(5). A modified cluster algorithm has been introduced to simulate the model with imaginary \theta. Two different definitions of the topological charge on the lattice have been used; one of them needs renormalization to match the continuum operator. Our work also offers a successful test for numerical methods based on analytic continuation.File in questo prodotto:
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