基于冷分子离子HD^(+)振转光谱的精密测量  

Precision measurement based on rovibrational spectrum of cold molecular hydrogen ion

作　　者：张乾煜 白文丽 敖致远 丁彦皓 彭文翠 何胜国 童昕 Zhang Qian-Yu;Bai Wen-Li;Ao Zhi-Yuan;Ding Yan-Hao;Peng Wen-Cui;He Sheng-Guo;Tong Xin(State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Wuhan Institute of Quantum Technology,Wuhan 430074,China)

机构地区：[1]中国科学院精密测量科学与技术创新研究院,波谱与原子分子物理国家重点实验室,武汉430071 [2]中国科学院大学,北京100049 [3]武汉量子技术研究院,武汉430074

出　　处：《物理学报》2024年第20期67-82,共16页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2021YFA1402103);国家自然科学基金(批准号:12393825)资助的课题.

摘　　要：由一个质子、一个氘核和一个电子组成的氢分子离子“HD^(+)”是最简单的异核双原子分子,其有着丰富的、可精确计算和测量的振转跃迁谱线.通过HD^(+)振转光谱实验测量和理论计算的对比,可实现物理常数的精确确定,量子电动力学理论的检验,并开启了超越标准模型新物理的探寻.目前,HD^(+)的振转跃迁频率确定的相对精度已经进入了10^(-12)量级,并由此获得了当前最高精度的质子电子质量比,相对精度达到20 ppt(1 ppt=10^(-12)).本文全面介绍了目前HD^(+)振转光谱的研究现状与理论背景,阐述了基于Be^(+)离子协同冷却HD^(+)分子离子的高精度振转光谱测量方法,包括Be^(+)离子和HD^(+)分子离子的产生与囚禁,HD^(+)外态冷却与内态制备,双组分库仑晶体中HD^(+)数目的确定,以及HD^(+)振转跃迁的探测.最后,文章展望了进一步提高频率测量精度的光谱前沿技术,及同位素氢分子离子的振转光谱在未来研究中的发展前景.A molecular hydrogen ion HD^(+),composed of a proton,a deuteron,and an electron,has a rich set of rovibrational transitions that can be theoretically calculated and experimentally measured precisely.Currently,the relative accuracy of the rovibrational transition frequencies of the HD^(+)molecular ions has reached 10^(-12).By comparing experimental measurements with theoretical calculations of the HD^(+)rovibrational spectrum,the precise determination of the proton-electron mass ratio,the testing of quantum electrodynamics(QED)theory,and the exploration of new physics beyond the standard model can be achieved.The experiment on HD^(+)rovibrational spectrum has achieved the highest accuracy(20 ppt,1 ppt=10^(-12))in measuring proton-electron mass ratio.This ppaper comprehensively introduces the research status of HD^(+)rovibrational spectroscopy,and details the experimental method of the high-precision rovibrational spectroscopic measurement based on the sympathetic cooling of HD^(+)ions by laser-cooled Be^(+)ions.In Section 2,the technologies of generating and trapping both Be^(+)ions and HD^(+)ions are introduced.Three methods of generating ions,including electron impact,laser ablation and photoionization,are also compared.In Section 3,we show the successful control of the kinetic energy of HD^(+)molecular ions through the sympathetic cooling,and the importance of laser frequency stabilization for sympathetic cooling of HD^(+)molecular ions.In Section 4,two methods of preparing internal states of HD^(+)molecular ions,optical pumping and resonance enhanced threshold photoionization,are introduced.Both methods show the significant increase of population in the ground rovibrational state.In Section 5,we introduce two methods of determining the change in the number of HD^(+)molecular ions,i.e.secular excitation and molecular dynamic simulation.Both methods combined with resonance enhanced multiphoton dissociation can detect the rovibrational transitions of HD^(+)molecular ions.In Section 6,the experimental setup and pr

关 键 词：振转光谱 HD^(+)分子离子 协同冷却 

分 类 号：O56[理学—原子与分子物理]