Principles of Digital Quantum Coprocessor Based on a FPGA, which Operates under the Control of a Classical Computer

Classical quantum computer is analog probabilistic computer. The digital quantum computer that can be implemented in FPGA is described in the article. Digital quantum coprocessor is designed to implement algorithms for execution on analog quantum computers. A digital quantum coprocessor operates under the control of a classical computer and together they are digital quantum computer. The digital quantum coprocessor is a set of digital units called digital qubits that have multibit data input and one bit data output each. The digital qubit is a wave function calculator. There is pseudo random number generator (PRNG) in described digital qubit to generate the probabilistic output bit. One bit qubit output qb is formed by the probable reduction of its multibit result x to one bit (0 or 1) according to result value x and pseudo random code k (x is an angle which determines the position of normalized vector with length 1 in polar grid, it is a result of multibit input data calculation). The decision about output state is made after the functional conversion of the qubit multibit result x to result probability p - sin.x and subsequent comparison p with the pseudo random code k. Qb -1 when k <; p (as in classical quantum computer). In article the alternative variant of decision option with p - arcsin(sqrt(k)) and qb - 1 when x > p is described. This variant allows use one PRNG for all digital qubits. Qubit presentation as vector in Bloch's sphere and vector in polar grid is discussed in the work. Also two types of coprocessor data formats (Cartesian and polar) are described. Instruction set of digital quantum coprocessor based in vector presentation in polar coordinates are discussed.