Atomic Landau-Zener tunneling and Wannier-Stark ladders in optical potentials.

Surface acoustic BLOCH oscillations, the Wannier-Stark ladder, and Landau-Zener tunneling in a solid.

We present the experimental observation of Bloch oscillations, the Wannier-Stark ladder, and Landau-Zener tunneling of surface acoustic waves in perturbed grating structures on a solid substrate. A model providing a quantitative description of our experimental observations, including multiple Landau-Zener transitions of the anticrossed surface acoustic Wannier-Stark states, is developed. The us...

Bloch oscillations, Zener tunneling, and Wannier-Stark ladders in the time domain.

Manifold Approach for a Many-Body Wannier Stark System: Localization and Chaos in Energy Space

We study the resonant tunneling e ect in a many-body Wannier Stark system, realized by ultracold bosonic atoms in an optical lattice subjected to an external Stark force. The properties of the many-body system are e ectively described in terms of upper-band excitation manifolds, which allow for the study of the transition between regular and quantum chaotic spectral statistics. We show that our...

Quantum tunneling of Bose-Einstein condensates in optical lattices under gravity.

We investigate the quantum tunneling of Bose-Einstein condensates in optical lattices under gravity in the "Wannier-Stark localization" regime and "Landau-Zener tunneling" regime. Our results agree with experimental data [B. P. Anderson et al., Science 282, 1686 (1998); F. S. Cataliotti et al., Science 293, 843 (2001)]. We obtain the total decay rate which is valid over the entire range of temp...

Atomic Landau-Zener tunneling in Fourier-synthesized optical lattices.

We report on an experimental study of quantum transport of atoms in variable periodic optical potentials. The band structure of both ratchet-type asymmetric and symmetric lattice potentials is explored. The variable atom potential is realized by superimposing a conventional standing wave potential of lambda/2 spatial periodicity with a fourth-order multiphoton potential of lambda/4 periodicity....