Universal Gate Set for Continuous-Variable Quantum Computation with Microwave Circuits

  1. Timo Hillmann,
  2. Fernando Quijandría,
  3. Göran Johansson,
  4. Alessandro Ferraro,
  5. Simone Gasparinetti,
  6. and Giulia Ferrini
We provide an explicit construction of a universal gate set for continuous-variable quantum computation with microwave circuits. Such a universal set has been first proposed in quantum-optical
setups, but its experimental implementation has remained elusive in that domain due to the difficulties in engineering strong nonlinearities. Here, we show that a realistic microwave architecture allows to overcome this difficulty. As an application, we show that this architecture allows to generate a cubic phase state with an experimentally feasible procedure. This work highlights a practical advantage of microwave circuits with respect to optical systems for the purpose of engineering non-Gaussian states, and opens the quest for continuous-variable algorithms based on a few repetitions of elementary gates from the continuous-variable universal set.