Deutsch's algorithm with topological charges of optical vortices via   non-degenerate four-wave mixing
  We propose a scheme to implement the Deutsch's algorithm through non-degenerate four-wave mixing process. By employing photon topological charges of optical vortices, we demonstrate the ability to realize the necessary four logic gates for all balanced and constant functions. We also analyze the feasibility of the proposed scheme on the single photon level. 
Mingtao Cao, Liang Han, Ruifeng Liu, Hao Liu, Dong Wei, Pei Zhang, Yu   Zhou, Wenge Guo, Shougang Zhang, Hong Gao, and Fuli Li
quant-ph physics.atom-ph