We study the phase diagram of the frustrated t−t′ Hubbard model on
the square lattice by using a novel variational wave function. Taking the clue
from the backflow correlations that have been introduced long-time ago by
Feynman and Cohen and have been used for describing various interacting systems
on the continuum (like liquid 3He, the electron jellium, and metallic
Hydrogen), we consider many-body correlations to construct a suitable
approximation for the ground state of this correlated model on the lattice. In
this way, a very accurate {\it ansatz} can be achieved both at weak and strong
coupling. We present the evidence that an insulating and non-magnetic phase can
be stabilized at strong coupling and sufficiently large frustrating ratio
t′/t.Comment: 8 pages, Proceedings of the HFM2008 Conferenc