Experimental demonstration of photonic quantum ratchet
  We created a potential for light with a phase mirror and then experimentally realized a photonic quantum ratchet in an all-optical system, in which ratchet effects can be observed with the naked eye up to more than 22 steps, and quantum resonance can be demonstrated. Our method also provides a new means to simulate quantum particles with classical light, and it can be applied to investigate many other quantum phenomena. 
Chi Zhang, Chuan-Feng Li and Guang-Can Guo
quant-ph physics.optics