EIT-based quantum light-matter interfaces using ultracold atoms

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We are trying to build a system to interface light and atoms at the quantum level. Quantum information processing promises capabilities beyond anything possible with current technology (absolutely unbreakable cryptographic systems, exponentially faster computation of certain algorithms, et cetera), but will require the invention of new techniques to realize. Already, quantum light (single photons) is used in commercial prototypes for secure communication, but turning such systems into computational devices will require some sort of "photon switch," since left to their own devices, one beam of light will placidly pass through another without any kind of interaction which could be used to compute. One of the most promising avenues for such technologies involves the use of atoms, which interact strongly with light. The problem is that so far, the interactions observed have been billions of times too weak to let individual quantum particles of light (photons) switch one another. Recent proposals suggest that it may be possible to close this gap, but this involves specially designed sources of light and carefully controlled laser-cooled atoms. We are fortunate in our lab to already have a "Bose-Einstein condensate" of Rubidium atoms (cooled to well below a millionth of a degree above absolute zero), and a novel source of quantum-entangled light we have developed specifically for interactions with Rubidium. This proposal will allow us to acquire two essential pieces of equipment for trapping and manipulating the atoms in the careful manner required for use in quantum logic, and for generating and tailoring the specific beams of light which are predicted to enhance the desired interaction. This is a highly competitive area of research internationally, but we are in an excellent starting position, and if we succeed, this unique capability will open new doors in atomic, molecular, and optical physics, and particularly for quantum information processing.