曲阜师范大学物理工程学院,山东 曲阜 273165
运用热力学统计中Kramers理论和Wentzel-Kramers-Brillouin(WKB)近似理论，分析了三结磁通量子比特中处于亚稳态粒子的热逃逸和量子隧穿逃逸。 在0.01?4.2 K温度下，计算出了粒子的逃逸率，得到了跳变磁通随磁场和温度变化的分布规律，并同两结超导干涉仪的分布规律进行了定量比较。结果显示， 三结磁通量子比特自身噪声比两结超导干涉仪大。
量子信息 磁通量子比特 亚稳态 约瑟夫森结 quantum information flux qubit metastable state Josephson junction
1 江西师范大学物理与通信电子学院, 江西 南昌 330022
2 江西省光电子与通信重点实验室,江西 南昌 330022
在二能级近似下运用Bloch-Redfield方程,研究了超导量子电路中的磁通量 子比特退相干在超欧姆热库 环境下受互感效应的影响。研究结果表明: 1)在超欧姆热库环境下,提高环境指标系数有利于延长 超导磁通量子比特的退相干时间; 2)构建超欧姆型热库环境可以改进固态量子比特的退相干; 3)电感元 件间的互感耦合对量子电路系统退相干的影响是比较复杂的,调控好电感元件间的互感耦合有利于提高退相干时间。
量子光学 退相干 磁通量子比特 超欧姆型热库 quantum optics decoherence flux quantum qubit super-Ohm thermal reservoir
Author Affiliations
Abstract
College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 3300222 Key Laboratory of Optoelectronic and Telecommunication of Jiangxi, Nanchang 3300223 Department of Physics, Anqing Teachers College, Anqing 246011
In the Born-Markov approximation and two-level approximation, and using the Bloch-Redfield equation, the decoherence property of superconducting quantum circuit with a flux qubit is investigated. The influence on decoherence of the mutual inductance coupling between the circuit components is complicated. The mutual inductance coupling between different loops will decrease the decoherence time. However, the mutual inductance coupling of the same loop, in a certain interval, will increase the decoherence time. Therefore, we can control the decoherence time by changing the mutual inductance parameters such as the strength and direction of coupling.
磁通量子比特 消相干 玻恩-马尔科夫近似 270.0270 Quantum optics 000.6800 Theoretical physics Chinese Optics Letters
2009, 7(1): 0178
