c(N). “Let us suppose that a universal quantum circuit, when run for exponential time failed to produce complexity greater than polynomial in the number of qubits. Consider some problem which is classically hard, i.e., it takes exponential time ∼ c(N) to solve it. It follows that there is a way to get to the answer in a polynomial number of steps running the computer as a quantum computer.”

https://lnkd.in/dByfCJV