摘要
量子计算的实际应用依赖于高保真度的量子门,而获得高保真度量子门所面临的主要挑战之一是系统的控制误差.几何相具有仅依赖系统演化路径而与演化速度大小等细节无关的特点,因此基于几何相设计的量子门具有抵抗系统控制误差的抗噪声性.特别是,基于非绝热非阿贝尔几何相设计的和乐量子门具有完全的几何性质,并且不受绝热缓慢演化条件的限制,受到了人们的广泛关注.本文提出了利用原子-腔系统实现非绝热和乐量子计算的方案.以四能级原子的基态作为逻辑量子比特编码空间的基矢,在激光脉冲的操控下,通过公共腔模交换虚光子产生双原子基态和辅助状态之间的跃迁,实现了两比特非绝热和乐受控相位门,它与通过激光脉冲操控单原子实现的任意单比特非绝热和乐门一起组成了非绝热和乐量子计算的通用量子门.
Quantum computation is much more effective than classical computation in solving many problems such as factoring large integers and searching unsorted databases.However,such effectiveness relies on the ability to perform universal highfidelity quantum gates.One main challenge in achieving such high-fidelity gates is to reduce control errors of a quantum system.To overcome this problem,various proposals of fault-tolerant quantum computation are proposed.A promising one of such proposals is nonadiabatic holonomic quantum computation.Nonadiabatic holonomic quantum computation is realized by using a quantum system with a subspace satisfying both the cyclic evolution and parallel transport conditions.For an N dimensional quantum system with Hamiltonian H(t)and evolution operator■,if there exists a time-dependent L dimensional subspace S(t)spanned by the orthonormal vectors■that satisfy the two conditions:(1)■,with being the evolution period,and(2)■l=1,2,,L,then the unitary transformation■is a holonomic gate on the L dimensional subspace S(0)spanned by■.The work of realizingnonadiabatic holonomic gate is to build a physical system with a Hamiltonian satisfying both the cyclic evolution condition and the parallel transport condition.Nonadiabatic holonomic quantum computation is based on nonadiabatic non-Abelian geometric phases.Since nonadiabatic non-Abelian geometric phases are only dependent on evolution paths but independent of evolution details,nonadiabatic holonomic gates are robust against control errors.Besides,nonadiabatic holonomic gates do not require the long run-time evolution that is necessary for adiabatic holonomic gates.Due to the merits of both robustness against control errors and high-speed realization,nonadiabatic holonomic quantum computation has received increasing attention in theory and experiment.Various schemes of nonadiabatic holonomic quantum computation have been proposed based on different physical systems,and a number of these schemes have been experimentally demonstrated with
作者
邢同昊
仝殿民
Tonghao Xing;Dianmin Tong(Department of Physics,Shandong University,Jinan 250100,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2020年第23期2499-2506,共8页
Chinese Science Bulletin
基金
国家自然科学基金(11775129)资助。
关键词
量子计算
几何相
和乐量子计算
原子-腔系统
quantum computation
geometric phases
holonomic quantum computation
atom-cavity system
