University of California and California Institute for Quantum Emulation, Santa Barbara, California 93105, USA.
Department of Physics and CeOPP, University of Paderborn, D-33098 Paderborn, Germany.
Phys Rev Lett. 2018 May 25;120(21):213201. doi: 10.1103/PhysRevLett.120.213201.
We report the observation and characterization of position-space Bloch oscillations using cold atoms in a tilted optical lattice. While momentum-space Bloch oscillations are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically unresolvable. In a regime of rapid tunneling and low force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.
我们报告了使用倾斜光晶格中的冷原子观察和描述位置空间布洛赫振荡的结果。虽然动量空间布洛赫振荡是光学晶格实验中的常见特征，但质心的实空间动力学通常无法解析。在快速隧穿和低力的情况下，我们观察到了数百个晶格位置的实空间布洛赫振荡幅度，包括基态和激发态能带。我们展示了通过在位置空间中跟踪布洛赫动力学实现的两种独特功能：测量布洛赫周期内的完整位置-动量相空间演化，以及直接成像晶格能带结构。这些技术以及无需调制即可对量子气体施加远距离相干控制的能力，可能为量子控制和计量学开辟新的可能性。
