Title: The strong-weak coupling symmetry in 2D Φ⁴ field models
Authors: B.N.Shalaev (A.F.Ioffe Physical & Technical Institute, Russian Academy of Sciences, Polytechnicheskaya str. 26, 194021 St.Petersburg, Russia)

It is found that the exact beta-function β(g) of the continuous 2D gΦ⁴ model possesses two types of dual symmetries, these being the Kramers-Wannier (KW) duality symmetry and the strong-weak (SW) coupling symmetry f(g), or S-duality. All these transformations are explicitly constructed. The S-duality transformation f(g) is shown to connect domains of weak and strong couplings, i.e. above and below g^*. Basically it means that there is a tempting possibility to compute multiloop Feynman diagrams for the β-function using high-temperature lattice expansions. The regular scheme developed is found to be strongly unstable.
Approximate values of the renormalized coupling constant g^* found from duality symmetry equations are in an agreement with available numerical results.

Key words: Kramers-Wannier duality, S-duality, renormalization group, beta-function
PACS: 11.25.Hf, 74.20.-z,05.10.Cc