Approach to the lower critical dimension of the ${\phi }^4$ theory in the derivative expansion of the Functional Renormalization Group

Lucija Nora Farkaš, Gilles Tarjus, Ivan Balog

We revisit the approach to the lower critical dimension $d_{\mathrm{lc}}$ in the Ising-like ${\phi }^4$ theory within the functional renormalization group by studying the lowest approximation…