Classical simulation of noninteracting-fermion quantum circuits

A new class of quantum computations, shown previously to be efficiently simulatable on a classical device, was analyzed. It was shown that the computations map onto a system of noninteracting fermions in one dimension. The equivalence give a straightforward derivation of the classical simulation, as well as extend the class of quantum computations to include noninteracting fermions without nearest-neighbor restrictions and gates that are applied conditionally on measurement outcomes.