Events at Physics |
The number of atoms in the trap is random and is commonly described by the Poissonian statistics. In the regime of Rydberg blockade an atomic ensemble, which consists of N atoms, can be treated as a two-level system with enhanced coupling to the laser radiation field by a factor of compared to a single atom. A single Rydberg excitation is shared between all atoms in the ensemble. Fluctuations of the frequency of Rabi oscillations between the collective states of the atomic ensembles can result in collapses and revivals of Rabi oscillations, similarly to Jaynes-Cummings model in quantum optics. These fluctuations can also lead to significant errors in quantum information processing. We have proposed to use the adiabatic passage in atomic ensembles for deterministic single-atom excitation and quantum logic gates in ensembles with unknown numbers of atoms. The double adiabatic sequences provide deterministic single-atom Rydberg excitation and remove the accumulation of undesirable dynamic phase. This can be used to implement quantum gates on collectively encoded qubits without precise knowledge of N.