Protocol for quantum-logical operations in an optical lattice using nonresonant absorption of photon pairs

Two nonidentical atoms may be entangled by inducing simultaneous cooperative absorption of a photon pair from a light field that is nonresonant to either atom in isolation. The atoms may be of two different elements, of different isotopes of the same element, or of a single isotope undergoing different transitions. Utilizing this cooperative process, we propose a protocol for a conditional operation with neutral atoms in an optical lattice. Current practical capabilities permit execution of the scheme.

Figure 1

The schematic energy level structure for ${}^{85}\mathrm{Rb}$ and ${}^{133}\mathrm{Cs}$, showing the electronic energy levels relevant to our example. Energy separations are not to scale and have been offset. The thin vertical arrows indicate the individual resonances and the thick vertical arrow, the NAPP resonance.