Decoherencia atómica en una zona de Ramsey fría

Abstract

Two-level atoms, almost in resonance with electromagnetic fields in cold low-quality-factor cavities pumped with a classical radiofrequency source, can be modeled as two-level systems interacting with a classical field. This model is faithful even if the average photon number, inside the cavity, is of the order of one, as has been reported in several experiments. If the atom-field coupling constant is much smaller than the inverse of the photon mean lifetime, the timedependent Weisskopf-Wigner approximation is valid and allows to show the following. The atomic decoherence characteristic time is inversely proportional to the product of the square of the coupling constant and the photon mean lifetime. In other words, if the cavity quality factor is small, the atom decouples from its environment. Under these con- ditions, the atom effectively couples to a “classical” field with mean number of photons equals to one.

Keywords

• Decoherencia
• Zonas de Ramsey
• Límite clásico.