Demonstration of a simple entangling optical gate and its use in   Bell-state analysis
  We demonstrate a new architecture for an optical entangling gate that is significantly simpler than previous realisations, using partially-polarising beamsplitters so that only a single optical mode-matching condition is required. We demonstrate operation of a controlled-Z gate in both continuous-wave and pulsed regimes of operation, fully characterising it in each case using quantum process tomography. We also demonstrate a fully-resolving, nondeterministic optical Bell-state analyser based on this controlled-Z gate. This new architecture is ideally suited to guided optics implementations of optical gates. 
N. K. Langford, T. J. Weinhold, R. Prevedel, K. J. Resch, A.   Gilchrist, J. L. O'Brien, G. J. Pryde and A. G. White (Univer...