Physics: A cold shake

Bryce Gadway

M. Kumakura, Y. Shirahata, Yosuke Takasu +2 more

By shaking a magnetic trap spatially, trapped cold Rb atoms are either heated or further cooled, depending on the shaking frequency. The atom temperature as a function of shaking frequency exhibits a dispersion-shaped resonance, which is caused by frequency selective energy absorption due to the anharmonicity of the trap potential. Selective heating of high-energy atoms enhances their loss, which can result in cooling rather than heating of a trapped atomic cloud.

Carl Wieman

Daniele Faccio

C. E. Creffield, G Pieplow, F Sols +1 more

Shaking a lattice system, by modulating the location of its sites periodically in time, is a powerful method to create effective magnetic fields in engineered quantum systems, such as cold gases trapped in optical lattices. However, such schemes are typically associated with space-dependent effective masses (tunneling amplitudes) and non-uniform flux patterns. In this work we investigate this phenomenon theoretically, by computing the effective Hamiltonians and quasienergy spectra associated with several kinds of lattice-shaking protocols. A detailed comparison with a method based on moving lattices, which are added on top of a main static optical lattice, is provided. This study allows the identification of novel shaking schemes, which simultaneously provide uniform effective mass and magnetic flux, with direct implications for cold-atom experiments and photonics.

Jürgen Jost