摘要
以周期驱动的量子Harper(quantum kicked Harper,QKH)模型为例,研究复杂量子动力系统的量子计算在各种干扰下的稳定性.通过对Floquet算子本征态的统计遍历性及其Husimi函数的分析,比较随机噪声干扰和静态干扰对量子计算不同程度的影响.进一步的保真度摄动分析表明,在随机噪声干扰下保真度随系统演化呈指数衰减,而静态干扰下的保真度为高斯衰减,并通过数值计算得到了干扰下的可信计算时间尺度.与经典混沌仿真中误差使状态产生指数分离不同,量子计算对状态干扰的稳定性和仿真模型的动力学特性无关.
The stability of quantum computating of the kicked Harper model with various perturbations is investigated. Above a certain threshold of the imperfections, quantum chaos sets in. The effects of the noise errors and the static imperfections on the quantum computation are analyzed by comparing the statistical ergodic properties and the Husimi functions of the perturbed eigenstates with the ideal eigenstates of the Floquet operator. It is shown that the fidelity decay with static imperfections is exponential while it is Gaussian with noise errors. The time scales of reliable computation with these perturbations are obtained through numerical simulations. Due to the errors in classical computation the distance of two initial states increases exponentially, while the stability of quantum computation is independent of the integrable or chaotic nature of the underlying dynamics.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第7期3709-3718,共10页
Acta Physica Sinica
