Resarch And Implementation Of Quantum Circuit On Construction Method

The combination and cascade of all types of quantum gates can constitute reversible logic quantum circuits, and then, a quantum computer is composed by quantum reversible logic circuits. In order to design a better reversible quantum circuit, we need to focus on the synthesis and optimization of reversible quantum circuits, i.e., synthesis algorithm. Quantum circuit optimization is to reduce the cost of the quantum circuit as much as possible by minimizing the number of circuit quantum gates, garbage quantum bits, and etc. based on the same quantum circuit function. Since quantum logic circuit is constituted by all kinds of quantum gates, we can also use the cascade of permutative and non-permutative gate to constitute more optimized quantum gates for replacing the original gates, and then the whole circuit can become more optimal. Therefore we conducted in-depth research on quantum gates and the synthesis algorithm of quantum circuits, the main research work and results are as follows:(1) The realization of Toffoli-Like gates using controlled-Kth-root-of-not quantum gates is presented. Since non-permutative quantum gates have more complex rules than permutative quantum gates, direct use of non-permutative quantum gates can greatly increase the complexity of the synthesis algorithm, so given quantum gates should be used to create new permutative quantum gates, and then these permutative gates are used to synthesize the desired quantum reversible logic circuit, thus the algorithm performance is improved. We focuse on how to use non-permutative quantum gates to construct new permutative gates, therefore, the idea of Gray code is absorbed to present an efficient recursive construction which can use controlled-Kth-root-of-NOT gates and controlled-K th-root-of-NOT gates(non-permutative quantum gates) to construct the optimal Toffoli-like gates(permutative quantum gates)(2) The design of barrel shifter based on quantum reversible logic is presented. A barrel shifter is a common component in the high-speed processor. It can shift a data word by specified number of bits in one clock cycle. Based on the quantum reversible logic circuit, the shifter with n inputs and k control bits is proposed, it is named as (n, k) shifter. For synthesizing the reversible shifter, our novel method is based on the decomposition of the permutation group, it only use (3,1) shifter and controlled swap gate to quickly synthesize any controlled shift with small quantum cost, and any (n, k) barrel shifter can be obtained by cascading minimal k corresponding (n,1) shifters.(3) The Visio-based automatically drawing of vector quantum circuit is presented. Quantum reversible logic circuits are very complicated to be drawed at present. The existing automatic drawing tools meet the needs of the basic drawing, but they can only draw the low-resolution bitmaps, and these kinds of bitmaps are difficult to meet the requirements of high-definition images when the paper was published. Therefore, further development of the Visio based drawing function is achieved by using C#, the description files of quantum circuits--TFC files are parsed, the parameters of many user-defined formats for circuits are read by c#, then the required quantum gates are drawn in turn, finally the high-definition vector graphs meeting the requirements are drawn automatically. The operation of quantum reversible logic circuits is for a specific signal, so the truth table can verify whether the circuit meets the requirements set in advance. It also provides a truth table of the quantum circuit to show and analyze the result of quantum circuits for users.