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两个主要挑战是克服系统的控制误差和环境噪声.几何相仅依赖于系统的演化路径而与演化速度等细节无关,因此基于几何相设计的量子门具有对控制误差的鲁棒性.特别是,基于非绝热非阿贝尔几何相设计的非绝热和乐(holonomic)门具有完全的几何性质并且不受绝热条件的限制,受到了人们的广泛关注.自2012年首次提出以来,非绝热和乐量子计算取得了很大的进展:人们逐步改进了非绝热和乐量子计算的设计理论,使得非绝热和乐门的设计不断优化;发展了抗退相干的非绝热和乐量子计算,使得量子门既能抵抗控制误差又能抵抗退相干;构建了基于各种具体物理系统的非绝热和乐量子计算方案,并且在实验上成功演示了非绝热和乐门.本文回顾了非绝热和乐量子计算的主要理论进展,并简要介绍了物理实现和实验工作.
Quantum computation has been shown to be superior to classical computation in solving some problems,and therefore can substantially change our life.However,the realization of quantum computation is still challenging,even if quantum technologies have been improved significantly.Two main obstacles to the realization of practical quantum computation are control errors and decoherence.Control errors are caused by inaccurate manipulations of quantum systems and decoherence is caused by the inevitable interaction between the system and its environment.Geometric phases are only dependent on evolution paths of quantum systems but independent of the evolution details and therefore quantum computation based on geometric phases,i.e.,geometric quantum computation,is robust against control errors,benefiting the realization of practical quantum computation.The early proposals of geometric quantum computation are based on adiabatic geometric phases.These proposals require quantum systems to undergo adiabatic evolution,which makes quantum systems evolve for a long time.To circumvent this,nonadiabatic geometric quantum computation based on nonadiabatic Abelian geometric phases was proposed soon after.In 2012,nonadiabatic holonomic quantum computation based on nonadiabatic non-Abelian geometric phases was proposed,which also circumvents long-time evolutions.Moreover,compared with nonadiabatic geometric quantum computation that uses the geometric phase as one parameter of a quantum gate,nonadiabatic holonomic quantum computation uses the holonomic matrix itself as a quantum gate.This makes nonadiabatic holonomic quantum computation possess whole-geometric property.Due to the merits of both geometric robustness and high-speed implementation without the limit of adiabatic evolution,nonadiabatic holonomic quantum computation has been attracting much attention.Until now,much progress has been achieved in the field of nonadiabatic holonomic quantum computation.On one hand,various methods have been proposed to design more efficient nonadiabatic holonomic gates.Nonadiabatic holonomic gates were first realized by using resonant laser fields to drive a three-level system.After this,the single-shot proposal and the single-loop proposal were proposed,allowing us to realize one-qubit gates by a shorter path and thereby reducing the exposure time of nonadiabatic holonomic gates to the environment.To further shorten the exposure time,the path-shortening protocol was put forward,where nonadiabatic holonomic gates can be realized based on a class of extended evolution paths that are shorter than the former ones.Recently,a general approach of constructing Hamiltonians for nonadiabatic holonomic quantum computation was put forward,by using which one can easily find a Hamiltonian making the quantum system evolve along a desired path so that nonadiabatic holonomic gates can be realized with an economical evolution time.On the other hand,various methods have been proposed to combine nonadiabatic holonomic gates and various decoherence-resilient methods,making the resulting schemes robust against both control errors and decoherence.The first proposal in this aspect is combining nonadiabatic holonomic gates and decoherence-free subspaces.Gradually,proposals combining nonadiabatic holonomic gates with noiseless subsystems,dynamical decoupling and surface codes were put forward.Last but not least,various proposals suitable for specific physical systems have been proposed and particularly various experimental platforms have been used to demonstrate nonadiabatic holonomic gates.This also significantly improves the development of nonadiabatic holonomic quantum computation.In this paper,we review the above research advances on nonadiabatic holonomic quantum computation,aiming to help readers understand the main developments of nonadiabatic holonomic quantum computation.
作者
赵培茈
许国富
仝殿民
Peizi Zhao;Guofu Xu;Dianmin Tong(Department of Physics,Shandong University,Jinan 250100,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2021年第16期1935-1945,共11页
Chinese Science Bulletin
基金
国家自然科学基金(11575101,11775129)资助。
关键词
几何相
非阿贝尔几何相
量子门
非绝热和乐量子计算
geometric phases
non-Abelian geometric phases
quantum gates
nonadiabatic holonomic quantum computation
