Artificial atoms can do more than atoms: Deterministic single photon   subtraction from arbitrary light fields
  We study the interplay of photons interacting with an artificial atom in the presence of a controlled dephasing. Such artifical atoms consisting of several independent scatterer can exhibit remarkable properties superior to single atoms with a prominent example being a superatom based on Rydberg blockade. We demonstrate that the induced dephasing allows for the controlled absorption of a single photon from an arbitrary incoming probe field. This unique tool in photon-matter interaction opens a way for building novel quantum devices and several potential applications like a single photon transistor, high fidelity n-photon counters, or for the creation of non-classical states of light by photon subtraction are presented. 
Jens Honer, Robert L\"ow, Hendrik Weimer, Tilman Pfau, and Hans Peter   B\"uchler
quant-ph