光晶格激发能带超冷原子的相干操控

项目名称： 光晶格激发能带超冷原子的相干操控

项目编号： No.61475007

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 周小计

作者单位： 北京大学

项目金额： 94万元

中文摘要： 周期性光晶格中的超冷原子或者玻色爱因斯坦凝聚，是对量子多体系统进行调控的理想平台，也是下一代高精度精密测量的基础。与目前对光晶格基带超冷原子的实验研究不同，本项目将集中针对光晶格激发能带的超冷原子进行操控。首先，利用提出的相干控制新方法，将谐振阱中超冷原子快速全部装载到一维光晶格的任意激发能带。这种方法有几个激光驻波脉冲序列组成，不管激发能带的宇称如何，都可以实现激发能带超冷原子的制备，且制备时间缩短了三个数量级。其次，不仅实现原子数在不同能带的不同比例装载，而且操控装载到不同能带波函数的相位，形成不同激发能带的叠加态，探讨其在信息存储上的优势。其三，实现三角型光晶格，研究这种情况下高激发能带原子的特性，实现新的量子态。最后，探讨各种因数对高激发能带中负有效质量的影响，将其利用到精密测量。总之，通过本项目，对超冷原子激发能带的性质有更深入的理解和认识，从而能很好的操控和应用。

中文关键词： 光晶格；超冷原子；激发能带；相干操控；驻波

英文摘要： The ultracold atomic gases or Bose-Einstein Condensate(BEC) in a periodic optical lattice is not only an ideal platform for manipulating quantum manybody system, but also the foundation of the future high accuracy precision measurement. In contrast to most of the experimental researches nowadays concerning the ground band of atoms in an optical lattice, this project focus on the excited bloch bands of the ultracold atomic gases in an optical lattice. First of all, utilizing our coherent manipulation method, which comprises several standing-wave laser sequences, we can load the ultracold atoms from the harmonic traps rapidly and coherently onto arbitrary excited bands of one dimentional optical lattice. Regardless of the parity of excited bands, the ultracold atoms can be effectively loaded onto any excited state, and the loading time is shorter by three orders of magnitude. Secondly, not only can we realize various atom number distributions on the bloch bands, the phases of the wavefunctions of the atoms loaded on each band can also be controlled, generating all kinds of superposition states of excited bands. Furthermore, we will realize two dimensional optical lattice with triangle geometry, and study its characteristic in excited bands. Finally, exploring the effect of various factors on the negative effective mass of high-energy-band atoms will reveal its advantages in presicion measurement. Therefore, this project will lead to a deeper understanding and a better control of ultracold atoms on excited states.

英文关键词： Optical lattice;Ultracold atoms;Excited band;Coherent manipulation;Standing waves