We study a quantum information storage scheme based on an atomic ensemble with near (also exact) three-photon resonance electromagnetically induced transparency (EIT). Each 4-level-atom is coupled to two classical control fields and a quantum probe field. Quantum information is adiabatically stored in the associated dark polariton manifold. An intrinsic non-trivial topological structure is discovered in our quantum memory implemented through the symmetric collective atomic excitations with a hidden SU(3) dynamical symmetry. By adiabatically changing the Rabi frequencies of two classical control fields, the quantum state can be retrieved up to a non-abelian holonomy and thus decoded from the final state in a purely geometric way.
@article{arxiv.quant-ph/0402177,
title = {Non-Abelian Geometric Quantum Memory with Atomic Ensemble},
author = {Y. Li and P. Zhang and P. Zanardi and C. P. Sun},
journal= {arXiv preprint arXiv:quant-ph/0402177},
year = {2009}
}