Dimensional expansion for the Ising limit of quantum field theory

Nov 15, 1993
10 pages
Published in:
  • Phys.Rev.D 48 (1993) 4919-4923
e-Print:

Citations per year

19942000200620122018012345
Abstract:
A recently-proposed technique, called the dimensional expansion, uses the space-time dimension DD as an expansion parameter to extract nonperturbative results in quantum field theory. Here we apply dimensional-expansion methods to examine the Ising limit of a self-interacting scalar field theory. We compute the first few coefficients in the dimensional expansion for γ2n\gamma_{2n}, the renormalized 2n2n-point Green's function at zero momentum, for n ⁣= ⁣2n\!=\!2, 3, 4, and 5. Because the exact results for γ2n\gamma_{2n} are known at D ⁣= ⁣1D\!=\!1 we can compare the predictions of the dimensional expansion at this value of DD. We find typical errors of less than 5%5\%. The radius of convergence of the dimensional expansion for γ2n\gamma_{2n} appears to be 2nn1{{2n}\over {n-1}}. As a function of the space-time dimension DD, γ2n\gamma_{2n} appears to rise monotonically with increasing DD and we conjecture that it becomes infinite at D ⁣= ⁣2nn1D\!=\!{{2n}\over {n-1}}. We presume that for values of DD greater than this critical value, γ2n\gamma_{2n} vanishes identically because the corresponding ϕ 2n\phi~{2n} scalar quantum field theory is free for D ⁣> ⁣2nn1D\!>\!{{2n}\over{n-1}}.
  • expansion: dimensional
  • field theory: scalar
  • n-point function
  • Ising model
  • expansion: strong coupling
  • strong coupling: expansion