phase transition, where the fluctuations of the Higgs field are of the order of $\phi_m$ while the hight of the “potential barrier”[^3] $H = V(0) - V(\phi_m)$ is of the order of $V(\phi_m + \delta \phi)-V(\phi_m)$, where $\delta \phi$ is the fluctuation of $|\Phi|$. We expect that in this region the perturbation expansion around trivial vacuum $\Phi = (\phi_m,0)^T$ cannot be applied. This region of the phase diagram is called the fluctuational region (FR).

The nature of the fluctuational region is illustrated by the behavior of quantum Nambu monopoles [@Nambu; @Chernodub_Nambu]. We show that their lattice density increases when the phase transition point is approached. Within the FR these objects are so dense that it is not possible at all to speak of them as of single monopoles [^4]. Namely, within this region the average distance between the Nambu monopoles is of the order of their size. Such complicated configurations obviously have nothing to do with the conventional vacuum used in the continuum perturbation theory.

The lattice model under investigation
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The lattice Weinberg - Salam Model without fermions contains gauge field ${\cal U} = (U,
\theta)$ (where $ \quad U
 \in SU(2), \quad e^{i\theta} \in U(1)$ are realized as 