The three-dimensional version of the Coleman–Weinberg model governs the superconducting phase transition which can be both first- and second-order, depending on the ratio of the Ginzburg–Landau parameter κ κ ≡ ≡ λ λ / e 2 , with a tricritical point near κ κ = 1 / 2 which separates type I from type II superconductivity. Historically, the order of the superconducting phase transition was debated for a long time since the temperature interval where fluctuations are large (Ginzburg interval) is extremely small. The question was finally settled in 1982. If the Ginzburg–Landau parameter κ κ that distinguishes type-I and type-II superconductors (see also here) is large enough, vortex fluctuations becomes important which drive the transition to second order. The tricritical point lies at roughly κ κ = 0.76 / 2 , i.e., slightly below the value κ κ = 1 / 2 where type-I goes over into type-II superconductor. The prediction was confirmed in 2002 by Monte Carlo computer simulations.