  The study of quantum frustrated systems remains one of the most challenging
subjects of quantum magnetism, as they can hold quantum spin liquids, whose
characterization is quite elusive. The presence of gapped quantum spin liquids
possessing long range entanglement while being locally indistinguishable often
demand highly sophisticated numerical approaches for their description. Here we
propose an easy computational method based on exact diagonalization with
engineered boundary conditions in very small plaquettes. We apply the method to
study the quantum phase diagram of diverse antiferromagnetic frustrated
Heisenberg models in the triangular lattice. Our results are in qualitative
agreement with previous results obtained by means of sophisticated methods like
2D-DMRG or variational quantum Monte Carlo.
