Circuit Optimization Of Grover Quantum Search Algorithm And Construction Of Simulation Platform

Grover quantum search algorithm is one of the most famous quantum algorithms and has attracted extensive attention since it was proposed.The algorithm can perform quadratic acceleration on the traditional unordered search algorithm and complete the tasks that cannot be solved by the traditional algorithm,which reflects the superiority of quantum computing.However,at the same time,this algorithm also has some problems:1.Traditional search methods can obtain the searched target element with 100%probability,but Grover quantum search algorithm has probabilistic measurement results due to its physical characteristics,which may require multiple searches to achieve the desired effect;2.The traditional search method is that the more target elements there are,the easier it will be to find the target elements.However,Grover algorithm has a higher success rate when the number of search targets reaches or exceeds half of total data;3.The implementation of Grover algorithm needs the support of a large number of quantum circuits.With the increase of searching data,its quantum circuits face complex gate decomposition problems.In today's NISQ era,resources are very limited.How to save resources and improve efficiency has become an important direction for the optimization of quantum search algorithm.Based on these problems,this paper makes the following research:First of all,by using Cirq quantum framework,the circuit of n-qubit Grover quantum search algorithm is simulated for the first time,and the characteristics and shortcomings of the algorithm are verified.Aiming at the shortage of search success rate,a precise quantum search algorithm based on phase angle rotation is introduced theoretically,and its simulation is implemented through Cirq framework,which verifies the effectiveness of the algorithm whose success rate is always 1.Secondly,a circuit optimization method is proposed to improve the efficiency of two-stage quantum search algorithm.The optimization method reduces the number of iterations by applying block-level oracle circuit.Combined with divide-and-conquer,this method is defined as 2P-Grover algorithm.Simulation experiments are carried out on the quantum framework Cirq and compared with Grover algorithm.Experimental results show that 2P-Grover algorithm can reduce the circuit depth by at least 1.2 times and maintain a high probability of search success.Thirdly,realize the quantum search algorithm circuit on the real quantum computer equipment and adopt different strategies to reduce the errors related to the implementation of the quantum search algorithm.The improved 2P-Grover search algorithm is implemented on IBM quantum processor.We prove that 3-qubit and 4-qubit search algorithm based on divideand-conquer has a higher success rate than previous work.Fourth,build a quantum circuit simulation platform based on the Cirq framework.Users can construct some simple quantum circuits and run them in simulation.The results are represented by histograms.They can also set algorithm parameters to run the quantum search algorithm for comparative experiments.