Quantum Break Time Research Articles

Experimental observation of dynamical localization and decoherence in the atomic -kicked rotor

We experimentally investigate decoherence by spontaneous emission in the quantum delta kicked rotor. Caesium atoms in a magneto-optic trap are initially cooled, and then subjected to a pulsed standing wave of near resonant light. As the detuning from the atomic transition is varied, we observe a change in the momentum diffusion after the quantum break time.

An experimental realization of the quantum -kicked rotor

We study experimentally quantum effects in atomic motion for a classically chaotic regime. A standing wave is pulsed on periodically in time, and the resulting atomic momentum is measured. Momentum grows diffusively until the quantum break time, after which dynamical localization is observed. Quantum resonances are observed for certain pulse durations.

Atom optics realization of the quantum delta -kicked rotor.

We report the first direct experimental realization of the quantum $\ensuremath{\delta}$-kicked rotor. Our system consists of a dilute sample of ultracold sodium atoms in a periodic standing wave of near-resonant light that is pulsed on periodically in time to approximate a series of delta functions. Momentum spread of the atoms increases diffusively with every pulse until the "quantum break time" after which exponentially localized distributions are observed. Quantum resonances are found for specific values of the pulse period.