Experimental Application of Decoherence-Free Subspaces in an Optical Quantum-Computing Algorithm
Masoud Mohseni, Jeff S. Lundeen, Katharina Resch, Aephraim M. Steinberg · Physical Review Letters · 2003
For a practical quantum computer to operate, it is essential to properly manage decoherence. One important technique for doing this is the use of "decoherence-free subspaces" (DFSs), which have recently been demonstrated. Here we present the first use of DFSs to improve the performance of a quantum algorithm. An optical implementation of the Deutsch-Jozsa algorithm can be made insensitive to a particular class of phase noise by encoding information in the appropriate subspaces; we observe a reduction of the error rate from 35% to 7%, essentially its value in the absence of noise.