| Quantum reversible computation is the kernel of quantum computation,and the quantum reversible circuit synthesis is the key technology in the construction of quantum computer.Most of quantum reversible circuit synthesis algorithms assum that arbitrary pairs of qubits can interact.However,several promising implementations of quantum computation rely on Linear Nearest Neighbor(LNN)architecture,which arrange quantum bits on a line,and allows neighbor interactions only.This paper focus on the construction and optimization for LNN architecture quantum circuits.The main contribution are as the following several aspects:1)Propose a new global reordering algorithm and a new local reordering algorithm.the redundancy of linear nearest neighbor quantum circuits can be reduced by changing the order of the qubits.It can be found that our algorithm is superior to existing algorithms through the experimental result of benchmark examples.2)A minimum quantum cost algorithm is proposed and all 3-qubit optimal circuits are synthesized.Utilizing the properties of LNN architecture quantum circuits,the impossible permutation and the quantum system states are discussed.A lot of non-optimal circuits are excluded when generating circuits,improving the efficiency of synthesis algorithm.3)Propose linear nearest neighbor implementation schemes for commonly used reversible gates,including Toffoli gate,Fredkin gate,Positive/Negative Control gate and Mutiple Control Toffoli(MCT)gate.Common reversible gate does not consider the problem of linear nearest neighbor,and not decomposed into LNN gates.Decomposing reversible gates cost into LNN quantum gate not only can reduce the redundancy of circuits,also can make it easier to convert circuits to LNN architecture.4)Designe a method for converting a quantum circuit to its equivament LNN architecture without decomposing non-elementary gates into a set of elementary unit-cost gates by reordering the circuit lines.Compared with the traditional method,new method can effectively improve the efficiency of converting algorithm beacause the length of circuits is greatly reduced. |
