Experimental Investigation of Nonideal Two-qubit Quantum-state Filter by Quantum Process Tomography

Abstract

We used quantum process tomography to investigate and identify the function of a nonideal two-qubit quantum-state filters subject to various degree of decoherence. We present a simple decoherence model that explains the experimental results and point out that a beamsplitter followed by a post-selection process is not, as commonly believed, a singlet-state filter. In the ideal case it is a triplet-state filter.

4 pages, 4 figures, RevTeX, to be published in Phys. Rev. Lett