六角晶格中Dirac准粒子的动力学模拟与操控

Simulation and Manipulation of Dirac Quasiparticles’ Dynamics in a Hexagonal Lattice

  • 摘要: 本文基于装载在六角可调光晶格中的超冷原子气体,研究了无质量狄拉克准粒子的动力学行为. 此系统与石墨烯具有类似的能带结构,即在简并点附近满足线性色散关系. 我们分别运用解析求解海森堡运动方程和数值波包动力学的方法,得到了准粒子质心位置. 我们可视化地展示了准粒子在不同宽度能隙处的演化行为. 结果发现准粒子的运动并没有出现相对论Zitterbewegung现象. 此外,我们还进一步研究了有效光速、Dirac旋量对系统动力学演化的影响. 结果表明波包的演化方式取决于初态Dirac旋子的形式,而运动速度只依赖于有效光速. 由于光晶格超冷原子系统具有纯净和高可操控性等优点,我们相信我们理论给出的有趣结果不久即可在超冷原子体系实验中得到验证.

     

    Abstract: We study the dynamical properties of massless Dirac quasiparticles with ultracold atomic gases in a hexagonal lattice. The system exhibit a similar energy level to graphene, which experience Dirac cone structure. We obtain the quasiparticles center of mass by analytical analysis and numerical simulation, respectively. The visualized evolution of quasiparticles is shown with different effective energy gap and the results show there is no Zitterbewegung. Furthermore, we investigate the influence of effective speed of light and initial spinors. We find the evolution of quasiparticles wave packet is dependent on the effective speed of light rather the initial spinor. Since the purity and high tunability, the observation of interesting phenomenon predict here is espectable in cold atomic system.

     

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