In a recently published work in Physical Review Letters, we have shown that artificial atoms made of a large number of single atoms can exhibit superior properties compared to their individual counterparts. Our results provide a way to novel applications in photonic devices used for quantum communication and quantum metrology.
In our work, we investigate an ensemble of strongly interacting atoms as found in Rydberg atoms or semiconductor quantum dots. The interaction of these systems with light can be described by an artificial atom with only two energy levels. However, when applying controlled noise to the system, this approximation breaks down and additional energy levels have to be taken into account. If a light beam is then sent through the system, these additional levels result in exactly one photon being removed from the beam. This single photon absorption process can be used in number resolving photon counters or for the creation of non-classical states of light.
Reference: J. Honer, R. Löw, H. Weimer, T. Pfau, H. P. Büchler, Phys. Rev. Lett. 107, 093601 (2011).
See also: Synopsis in Physics