LAUSR

We propose an optical scheme to encode quantum information into three-photon decoherence-free states (single logical qubit information) and thereby acquire immunity from collective decoherence. Our scheme consists of quantum dots (QDs) within single-sided optical cavities and linearly optical devices for generation of three-photon decoherence-free states (logical qubits) and for encoding arbitrary quantum information. In our proposition, the interaction between photons and electron spin in the QD-cavity system is the critical component and plays the role of a quantum controlled operation to perform the processing of single logical qubit information with immunity against collective decoherence. Thus, we also analyze the performance of interaction between a photon and an electron in a QD. Consequently, for generating three-photon decoherence-free state encoded arbitrary quantum information, our scheme using QD-cavity systems is feasible. In practice, it could be implemented experimentally with current technologies.