Monte Carlo determination of the critical coupling in ${\varphi }_2^4$ theory

We use lattice formulation of ${\varphi }^4$ theory in order to investigate non–perturbative features of its continuum limit in two dimensions. In particular, by means of Monte Carlo calculations, we obtain the critical coupling constant $g\mathrm{/}{\mu }^2$ in the continuum, where $g$ is the {\em unrenormalised} coupling. Our final result is $g\mathrm{/}{\mu }^2=11.15(6)(3)$.