超导离子芯片的近场热噪声引起的离子加热研究

J4 ›› 2018, Vol. 35 ›› Issue (4): 432-438.

超导离子芯片的近场热噪声引起的离子加热研究

徐志兵,张波,杨波,刘子龙,毛如圣

武汉理工大学理学院物理系，湖北武汉 430070

收稿日期:2017-04-18 修回日期:2017-05-04 出版日期:2018-07-28 发布日期:2018-07-12
通讯作者: 张波(1977-),女,湖北人,博士,教授,主要从事量子光学方面的研究。 E-mail:zhangbo2011@whut.edu.cn
作者简介:徐志兵(1990-),湖北人,硕士,主要从事量子光学方面的研究。E-mail: xuzhibing@whut.edu.cn
基金资助:
Supported by Fundamental Research Funds for the Central Universities （中央高校基本科研业务费专项资金，WUT: 2016-IA-008）

Ion heating induced by near-field thermal noise of superconducting ion chip

XU Zhibing, ZHANG Bo, YANG Bo, LIU Zilong, MAO Rusheng

Department of Physics, School of Science, Wuhan University of Technology, Wuhan 430070, China

Received:2017-04-18 Revised:2017-05-04 Published:2018-07-28 Online:2018-07-12

摘要/Abstract

摘要：

基于涨落耗散定理研究了不同温度下超导离子芯片中近场热噪声引起的离子加热效应，通过电场格林函数和多层介质反射系数得到了不同情况下电场涨落谱密度的近似式。对于净铌电极，当温度T为295 K时，近场热噪声谱密度与电极厚度成反比；T为4 K时，近场热噪声谱密度与电极厚度无关，且通过计算发现其近场热噪声相较于室温下降了十几个数量级。分析了铌电极表面存在薄膜的情况，结果表明层薄膜引起的电场涨落占据主要地位，噪声谱密度与厚度成正比，芯片温度降至4 K时其热噪声下降5～6个量级。

关键词: 量子光学；近场热噪声；涨落耗散定理；超导离子芯片

Abstract:

Ion heating effect incuced by near-field thermal noise of superconducting ion chip at different temperatures is investigated based on fluctuation-dissipation theorem. The approximate expressions of electric field fluctuation spectral density under different conditions are obtained by the electric field Green function and multi-layer reflection coefficients. For pure Nb electrode, the near-field thermal noise spectral density is inversely proportional to the electrode thickness when the temperature T is 295 K. The near-field thermal noise spectral density is irrelevant with the electrode thickness when T is 4 K, and the near-field thermal noise can be reduced by over ten orders of magnitude comparing to the case of room temperature. The case that there are thin films on the surface of niobium electrode is analyzed. Results show that the electric field fluctuation induced by film occupies the main position. The noise spectral density is proportional to the thickness. When chip temperature decreases to 4 K, the thermal noise decreases by 5 to 6 orders of magnitude.

Key words: quantum optics; near-field thermal noise; fluctuation-dissipation theorem; superconducting ion chip

中图分类号:

O431.2

徐志兵张波杨波刘子龙毛如圣. 超导离子芯片的近场热噪声引起的离子加热研究[J]. J4, 2018, 35(4): 432-438.

XU Zhibing, ZHANG Bo, YANG Bo, LIU Zilong, MAO Rusheng. Ion heating induced by near-field thermal noise of superconducting ion chip[J]. J4, 2018, 35(4): 432-438.

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