The two- and three-dimensional transverse-field Ising models with
ferromagnetic exchange interactions are analyzed by means of the real-space
renormalization group method. The basic strategy is a generalization of a
method developed for the one-dimensional case, which exploits the exact
invariance of the model under renormalization and is known to give the exact
values of the critical point and critical exponent ν. The resulting values
of the critical exponent ν in two and three dimensions are in good
agreement with those for the classical Ising model in three and four
dimensions. This is the first example in which a real-space renormalization
group on (2+1)- and (3+1)-dimensional Bravais lattices yields accurate
estimates of the critical exponents.Comment: 14 pages, 5 figures, 4 table