Qubit-Programmable Operations on Quantum Light Fields
  Engineering quantum operations is one of the main abilities we need for developing quantum technologies and designing new fundamental tests. Here we propose a scheme for realising a controlled operation acting on a travelling quantum field, whose functioning is determined by an input qubit. This study introduces new concepts and methods in the interface of continuous- and discrete-variable quantum optical systems. 
Marco Barbieri, Nicol\`o Spagnolo, Franck Ferreyrol, R\'emi Blandino,   Brian J. Smith, and Rosa Tualle-Brouri
quant-ph