Delay of Entangled Images with Four-Wave Mixing


A. M. Marino, R. C. Pooser, V. Boyer, P. D. Lett,

National Institute of Standards and Technology, Gaithersburg, MD 20899.


Quantum information and computing systems use quantum mechanics to manipulate and transmit information. Information processing benefits from quantum mechanics because of entanglement, a property that is not observable in the classical world. Entanglement consists of correlations between the fluctuations of quantum systems that are better than can be obtained classically. It is instrumental in the exponential speedup in calculation time that quantum computers are expected to display and in the increased security of information that quantum communication brings.


Quantum networks will play a key role in quantum information processing by making it possible to distribute quantum correlations between different nodes in the network. A key ingredient for quantum networks is the ability to control the flow of the correlated fluctuations between those nodes. This requires a system that can delay the fluctuations without significantly degrading the correlations, effectively acting as a short term quantum memory. Here, we show that a nonlinear interaction, called four-wave mixing, in an atomic medium provides a system that can slow the velocity of light beams traversing the medium while preserving the correlations. Using our system we are able to introduce a relative delay between two entangled beams of light, thereby creating a quantum information delay-line, or potentially a short term quantum memory. Further the system was used to delay multiple spatial optical modes simultaneously. This allows us to delay complicated entangled spatial patterns, which we call entangled images.












Mentors Name: Paul Lett

Atomic Physics Division, Physics Laboratory