Effect on ion-trap quantum computers from the quantum nature of the driving field  

作　　者：Biyao YANG Li YANG 

机构地区：[1]State Key Laboratory of Information Security,Institute of Information Engineering,Chinese Academy of Sciences,Beijing 100049,China [2]State Key Laboratory of Cryptology,P.O.Box 5159,Beijing 100878,China [3]School of Cyber Security,University of Chinese Academy of Sciences,Beijing 100093,China [4]Beijing Institute of Information Application Technology,Beijing 100044,China

出　　处：《Science China(Information Sciences)》2020年第10期215-229,共15页中国科学（信息科学）（英文版）

基　　金：supported by National Natural Science Foundation of China(Grant No.61672517);National Cryptography Development Fund(Grant No.MMJJ20170108);National Key R&D Program of China(Grant No.2016QY03D0503);Beijing Municipal Science&Technology Commission(Grant No.Z191100007119006)。

摘　　要：In this study,we evaluate the effect on ion-trap quantum computers(QCs)from the quantum nature of the driving field,and propose a theoretical limit for ion-trap QCs that may impact the design of quantum algorithms and realization of practical QCs.We obtain,for the first time,the permitted depth of logical operation for fault-tolerant ion-trap QCs.Physically,we provide an exact(full-quantum)description of the QC system,and present for the first time its time evolution after gate operations;mathematically,we solve problems such as certain summations of trigonometric series with any given precision.Comparing the actual state after CNOT gates driven by a quantized field with the expected state,we obtain the failure probability and estimate that the number of CNOT gates on the same pair of physical qubits is not more than 10^2 in one error-correction period,which is a physical limit that cannot be easily overcome.The conclusion can help determine the number of CNOT operations between coding and decoding in one error-correction period and can be used as a reference for quantum algorithm design.

关 键 词：quantum computing ION-TRAP quantum algorithm fault-tolerant quantum computation threshold theorem permitted depth of logical operation 

分 类 号：O413[理学—理论物理] TP38[理学—物理]