Meron cluster simulation of the theta vacuum in the 2-d O(3) model

May, 1995
8 pages
Published in:
  • Phys.Rev.Lett. 75 (1995) 4524-4527
e-Print:
Report number:
  • MIT-CTP-2433

Citations per year

1995200320112019202502468
Abstract:
The 2-d O(3)O(3)-model with a θ\theta-vacuum term is formulated in terms of Wolff clusters. Each cluster carries a half-integer topological charge. The clusters with charge ±1/2\pm 1/2 are identified as merons. At θ=π\theta = \pi the merons are bound in pairs inducing a second order phase transition at which the mass-gap vanishes. The construction of an improved estimator for the topological charge distribution makes numerical simulations of the phase transition feasible. The measured critical exponents agree with those of the k=1k = 1 Wess-Zumino-Novikov-Witten model. Our results are consistent with Haldane's conjecture for 1-d antiferromagnetic quantum spin chains.
  • lattice field theory
  • model: spin
  • spin: model
  • dimension: 2
  • symmetry: O(3)
  • charge: topological
  • Theta parameter
  • vacuum state
  • expansion: cluster
  • critical phenomena