We report on the observation of ultralong range interactions in a gas of cold rubidium Rydberg atoms. The van der Waals interaction between a pair of Rydberg atoms separated as far as 100,000 Bohr radii features two important effects: spectral broadening of the resonance lines and suppression of excitation with increasing density. The density dependence of these effects is investigated in detai...

This paper presents the results of two years of operation of an automatic system that compensates drifts of a rubidium atomic clock. This clock is the base of the Uruguayan National Time-Frequency Standard.

We experimentally demonstrate a communication protocol that enables frequency conversion and routing of quantum information in an adiabatic and thus robust way. The protocol is based on electromagnetically induced transparency (EIT) in systems with multiple excited levels: transfer and/or distribution of optical states between different signal modes is implemented by adiabatically changing the ...

We report experimental observation of three-field noise correlation between two coexisting four-wave mixing (FWM) signals and the probe signal in a coherently-prepared rubidium vapor system. The two FWM signals in a double-Λ type quasi-four-level atomic system are obtained in different directions via their respective phase-matching conditions and can be detected individually. These signals and ...

A gas of Rb atoms in a static electric field has been photoexcited to just above the classical ionization threshold by a phase-locked sequence of two far infrared pulses. A single laser pulse generates a series of ejected electron packets emerging at the saddle point of the potential; each of the ejected packets is characterized by a phase and a chirp. We calculate and measure these phases and ...