| Turing was familiar with the Jacquard loom for weaving patterns on punch cards and Babbage's, and was then tasked with brute-forcing a classical cipher. Quantum wave theory existed but wasn't considered necessary for classical brute-forcing. For example, Shor's algorithm for integer factorization was published in 1994. Turing's paper does not specify concurrency, local or distributed. (Though is non-distributed multi-core local concurrency just also a Turing Machine?) Is anything sufficient? From "Church–Turing–Deutsch principle" https://en.m.wikipedia.org/wiki/Church%E2%80%93Turing%E2%80%... : > The principle was stated by Deutsch in 1985 with respect to finitary machines and processes. He observed that classical physics, which makes use of the concept of real numbers, cannot be simulated by a Turing machine, which can only represent computable reals. Deutsch proposed that quantum computers may actually obey the CTD principle, assuming that the laws of quantum physics can completely describe every physical process. Do modern QC allow a continuum of computable reals either? Not really yet, no; not with qubits, qudits or qutrits is there a complete real (0,1) interval. There are mean Expectation Values even on actual QC instead of quantum circuit simulators where it's either 0 or 1 for that run of the sim. TASK: Represent e.g. π+1e-10 on a classical and then a modern quantum computer. How many quantizations of theta π can there be? And then with Bloch sphere rotations we have every possible unitary quantum operator? And still there can be side channels in formally-verified classical and classical+quantum computers. |