LETTERS TO THE EDITORS

# Quantum Light

To the Editors:

I found the article by Drs. Franke-Arnold and Arnold ("Twisting Light to Trap Atoms," May-June) to be extremely interesting. I am a mathematical and theoretical physicist working at present on generalized models of quantum computation and quantum algorithms. In our proposed "spin network quantum simulator," published in *Annals of Physics* in 2005, basic unitary gates are represented by recoupling between alternative (binary coupled) schemes of pure many-angular momentum states (not restricted to spin 1/2 qubits). I think that the experimental setting you are working on could be looked at as a possible physical implemen-tation of this kind of simulator.

Annalisa Marzuoli

University of Pavia, Italy

Dr. Franke-Arnold responds:

Dr. Marzuoli draws similarities between our research and her own work on quantum information protocols. Orbital angular momentum of light is a convenient testing ground for quantum information in higher dimensions, so it might be interesting to devise experiments to try to confirm her work.

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