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On the computational power of probabilistic and quantum branching program
2005
Information and Computation
In this paper, we show that one-qubit polynomial time computations are as powerful as NC 1 circuits. More generally, we define syntactic models for quantum and stochastic branching programs of bounded width and prove upper and lower bounds on their power. We show that any NC 1 language can be accepted exactly by a width-2 quantum branching program of polynomial length, in contrast to the classical case where width 5 is necessary unless NC 1 = ACC. This separates width-2 quantum programs from
doi:10.1016/j.ic.2005.04.003
fatcat:mncsgr5c5rhn3h7yh7izipf6du