Renormalization-group transformation for quantum lattice systems at zero temperature

We propose a new renormalization-group (RG) method applicable to quantum systems defined on a lattice at zero temperature. We apply our method to the one-dimensional Ising model in a transverse field and the two-dimensional triangular Ising model in a transverse field. In both cases, a nontrivial fixed point of our RG transformation is found. Critical exponents are calculated and compared with exact and previous RG results.