Abstract: A quantum compiler is a software program that runs on a classical computer. It can decompose (“compile”) an arbitrary unitary matrix into a sequence of elementary operations (SEO) that a quantum computer can follow. A quantum compiler previously invented by Tucci decomposes an arbitrary unitary matrix Uin into a sequence of U(2)-multiplexors, each of which is then decomposed into a SEO. A preferred embodiment of this invention is a subroutine within a quantum compiler program. The subroutine approximates some or all of the intermediate U(2)-multiplexors whose product equals Uin.

Abstract: The invention comprises a classical computer that runs a special computer program. The program takes as input an initial data-set that comprises probabilistic information and returns as output a sequence of elementary operations (SEO). The initial data-set helps determine a classical Bayesian (CB) net. A program called “Q-Embedder” embeds the CB net within a quantum Bayesian (QB) net. A program called “Qubiter” (a quantum compiler) then translates the QB net into an equivalent SEO. The SEO outputted by the classical computer can be used to manipulate an array of qubits in a quantum computer. Application of the SEO to the array, followed by a measurement of the array, yields the value of certain conditional probabilities that we wish to know. The main goal of the invention is to provide a method for performing classical Bayesian net calculations on a quantum computer. Such calculations can be done on a classical computer; the hope is that they can be done much faster on a quantum computer.

Abstract: A quantum computer is an array of quantum hits (qubits) together with some hard-ware for manipulating these qubits. Quantum Bayesian (QB) nets are a method of modeling quantum systems graphically in terms of network diagrams. This invention comprises a classical computer running a Computer program that expresses the information contained in a QB net as a sequence of elementary operations (SEO). One can then run these sequences on a quantum computer. We show how to reduce a QB net into a SEO by a two step process. First, express the information contained in the QB net as a sequence of unitary operators. Second, express each of those unitary operators as a SEO. An appendix to this document contains the C++ source code of a computer program called “Qubiter1.0”, which is a preferred embodiment of the invention.