Topological aspects of spin and statistics in nonlinear sigma models

May, 1992
14 pages
Published in:
  • J.Math.Phys. 36 (1995) 247-257
e-Print:
Report number:
  • PRINT-92-0332 (WELLESLEY)

Citations per year

1995200220092016202310
Abstract: (arXiv)
We study the purely topological restrictions on allowed spin and statistics of topological solitons in nonlinear sigma models. Taking as space the connected dd-manifold XX, and considering nonlinear sigma models with the connected manifold MM as target space, topological solitons are given by elements of pid(M)pi_d(M). Any topological soliton απd(M)\alpha \in \pi_d(M) determines a quotient \Stat_n(X,\alpha) of the group of framed braids on XX, such that choices of allowed statistics for solitons of type α\alpha are given by unitary representations of \Stat_n(X,\alpha) when nn solitons are present. In particular, when M=S 2M = S~2, as in the O(3)O(3) nonlinear sigma model with Hopf term, and απ2(S 2)\alpha \in \pi_2(S~2) is a generator, we compute that \Stat_n(\R~2,\alpha) = \Z, while \Stat_n(S~2,\alpha) = \Z_{2n}. It follows that phase exp(iθ)\exp(i\theta) for interchanging two solitons of type α\alpha on S 2S~2 must satisfy the constraint θ=kπ/n\theta = k\pi/n, kZk \in \Z, when nn such solitons are present.
  • sigma model: nonlinear
  • topology
  • spin: statistics
  • statistics: spin
  • field equations: soliton
  • soliton: topological
  • Hopf term
  • braid group
  • bibliography