Using continuous measurement to protect a universal set of quantum gates within a perturbed decoherence-free subspace

Paulo E M F Mendonça, Marcelo A Marchiolli, Reginaldo d J Napolitano
2005 Journal of Physics A: Mathematical and General  
We consider a universal set of quantum gates encoded within a perturbed decoherence-free subspace of four physical qubits. Using second-order perturbation theory and a measuring device modeled by an infinite set of harmonic oscillators, simply coupled to the system, we show that continuous observation of the coupling agent induces inhibition of the decoherence due to spurious perturbations. We thus advance the idea of protecting or even creating a decoherence-free subspace for processing quantum information.
doi:10.1088/0305-4470/38/6/l04 fatcat:rlqhaefr7zgdfppisff3su5hme