Mochol Małgorzata, Sacha Krzysztof
Instytut Fizyki imienia Mariana Smoluchowskiego and Mark Kac Complex Systems Research Center, Uniwersytet Jagielloński, ulica prof. Stanisława Łojasiewicza 11, PL-30-348 Kraków, Poland.
Sci Rep. 2015 Jan 8;5:7672. doi: 10.1038/srep07672.
Cold atomic gases are perfect laboratories for realization of quantum simulators. In order to simulate solid state systems in the presence of magnetic fields special effort has to be made because atoms are charge neutral. There are different methods for realization of artificial magnetic fields, that is the creation of specific conditions so that the motion of neutral particles mimics the dynamics of charged particles in an effective magnetic field. Here, we consider adiabatic motion of atoms in the presence of an evanescent wave. Theoretical description of the adiabatic motion involves artificial vector and scalar potentials related to the Berry phases. Due to the large gradient of the evanescent field amplitude, the potentials can be strong enough to induce measurable effects in cold atomic gases. We show that the resulting artificial magnetic field is able to induce vortices in a Bose-Einstein condensate trapped close to a surface of a prism where the evanescent wave is created. We also analyze motion of an atomic cloud released from a magneto-optical trap that falls down on the surface of the prism. The artificial magnetic field is able to reflect falling atoms that can be observed experimentally.
冷原子气体是实现量子模拟器的理想实验室。由于原子是电中性的，为了在磁场存在的情况下模拟固态系统，必须付出特殊努力。实现人工磁场有不同的方法，即创造特定条件，使中性粒子的运动模仿有效磁场中带电粒子的动力学。在这里，我们考虑原子在消逝波存在下的绝热运动。绝热运动的理论描述涉及与贝里相位相关的人工矢量和标量势。由于消逝场振幅的大梯度，这些势足够强，能够在冷原子气体中诱导出可测量的效应。我们表明，由此产生的人工磁场能够在捕获于棱镜表面附近（产生消逝波的地方）的玻色-爱因斯坦凝聚体中诱导出涡旋。我们还分析了从磁光阱释放并落到棱镜表面的原子云的运动。人工磁场能够反射下落的原子，这一点可以通过实验观察到。
