浅光晶格中量子隧穿现象的实验观测  

Experimental observation of quantum tunneling in shallow optical lattice

作　　者：李婷 汪涛[3,4] 王叶兵 卢本全[1] 卢晓同[1] 尹默娟 常宏 Li Ting;Wang Tao;Wang Ye-Bing;Lu Ben-Quan;Lu Xiao-Tong;Yin Mo-Juan;Chang Hong(Key Laboratory of Time and Frequency Primary Standards,National Time Service Center,CAS,Xi’an 710600,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China;Center of Quantum Materials and Devices,College of Physics,Chongqing University,Chongqing 401331,China;Chongqing Key Laboratory for Strongly Coupled Physics,Chongqing 401331,China)

机构地区：[1]中国科学院国家授时中心,时间频率基准重点实验室,西安710600 [2]中国科学院大学,天文与空间科学学院,北京100049 [3]重庆大学物理学院,量子材料与仪器中心,重庆401331 [4]强关联物理重庆重点实验室,重庆401331

出　　处：《物理学报》2022年第7期99-106,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11803042,61775220);中国科学院青年创新促进会(批准号:2019400);国家理论物理研究专项基金(批准号:11647165);中国博士后科学基金面上项目(批准号:2020M673118)资助的课题。

摘　　要：基于一维水平光晶格的锶原子光晶格钟实验平台,当系统的稳定度和不确定度达到10-18量级以上时,由量子隧穿效应引起的钟频移变得不容忽视.在浅光晶格中,量子隧穿效应会使钟跃迁谱线发生明显的展宽现象,因此,本文通过研究浅光晶格中的量子隧穿现象,为^(87)Sr原子光晶格钟系统不确定度的评估奠定基础.本实验在一维^(87)Sr原子光晶格钟平台上,利用超稳超窄线宽的698 nm激光激发^(87)Sr冷原子^(1)S_(0)(|g>)→^(3)P_(0)(|e>)跃迁(即钟跃迁),实现了对锶原子分布在特定量子态的制备.在深光晶格中,将原子制备到|e,n_(z)=1>态后,再绝热地降低光晶格阱深,然后在浅光晶格中,探测激发态的载波-边带可分辨的钟跃迁谱线.从钟跃迁谱线中观测到载波谱线发生了明显的劈裂,表明原子在光晶格相邻格点间产生了明显的量子隧穿现象.通过对光晶格中量子隧穿机制的理解,不仅有利于提高光晶格钟的不确定度,也可为观测光晶格中费米子的自旋轨道耦合效应提供基础数据.For a one-dimensional optical lattice clock built in the horizontal direction,when the stability and uncertainty of the system reach the order of 10;or more,the clock frequency shift caused by the quantum tunneling effect becomes not negligible.In the shallow optical lattice,the quantum tunneling effect will cause the clock transition spectrum to be significantly broadened.So,in this paper the quantum tunneling phenomenon in the shallow optical lattice is studied,laying a foundation for the evaluation of uncertainty of^(87)Sr atomic optical lattice clock system.In this experiment,on the platform of one-dimensional^(87)Sr atomic optical lattice clock,the narrow-linewidth^(1)S_(0)(|g>)→^(3)P_(0)(|e>)transition(that is,the clock transition)is excited by an ultra-stable and ultra-narrow linewidth 698 nm laser,and the distribution of strontium atoms in a specific quantum state is prepared.In the deep optical lattice,after the cold^(87)Sr atoms in preparation reach a|e,n_(z)=1)state,the lattice depth of the optical lattice is adiabatically reduced.Then,the carrier-sideband resolved clock transition spectral line is detected in the shallow optical lattice.The obvious splitting of the carrier spectral line is observed from the clock transition spectral line,which indicates that the strontium atom has an obvious quantum tunneling phenomenon between the adjacent lattice sites of the optical lattice.In addition,when the lattice potential lattice depth is reduced,owing to the incommensurability of lattice light wavelength(813 nm)and clock laser wavelength(698 nm),the tunneling of atoms between adjacent lattice points will lead to spinorbit coupling effect.Owing to the exceptionally long lifetime(120(3)s)of^(8)P_(0)state,it can not only suppress the decoherence,but also reduce the atomic loss rate caused by spontaneous emission.This has a natural advantage for studying the spin-orbit coupling of fermions.Therefore,the understanding of quantum tunneling mechanism in optical lattice is not only conducive to improving the unce

关 键 词：光晶格 钟跃迁谱线 量子态 隧穿现象 

分 类 号：O469[理学—凝聚态物理]