Experimental demonstration of decoherence-free one-way quantum information processing

In recent years, one-way quantum computing has become an exciting alternative to existing proposals for quantum computers. In this specific model, coherent quantum information processing (QIP) is accomplished via a sequence of single-qubit measurements applied to an entangled resource known as cluster state. However, there has so far been no experimental realization of noise-resilient quantum computation in the one-way model. Here we report the experimental demonstration of a one-way quantum processor reliably operating under the effects of decoherence. Information is protected by a properly designed decoherence-free subspace in which the cluster states reside. We demonstrate our scheme in an all-optical setup by encoding the information into the polarization states of four photons. A one-way information-transfer protocol is performed with the photons exposed to severe symmetric phase damping noise. Remarkable protection of information is accomplished, delivering nearly ideal computational outcomes.