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

Physical Review Letters, vol. 125, pp. 160501

Abstract

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 three-wave mixing microwave architecture based on the superconducting nonlinear asymmetric inductive element [Frattini et al., Appl. Phys. Lett. 110, 222603 (2017)APPLAB0003-695110.1063/1.4984142] allows us to overcome this difficulty. As an application, we show that this architecture allows for the generation of 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 few repetitions of elementary gates from the continuous-variable universal set.

Authors 6

1. Timo Hillmann Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University · Chalmers University of Technology

   Affiliation as printed

   Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

   Institut für Theorie der Statistischen Physik, RWTH Aachen, 52056 Aachen, Germany

2. Fernando Quijandría

   Chalmers University of Technology

   Affiliation as printed

   Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

3. Göran Johansson

   Chalmers University of Technology

   Affiliation as printed

   Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

4. Alessandro Ferraro

   Queen's University Belfast

   Affiliation as printed

   Centre for Theoretical Atomic, Molecular and Optical Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom

5. Simone Gasparinetti

   Chalmers University of Technology

   Affiliation as printed

   Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

6. Giulia Ferrini

   Chalmers University of Technology

   Affiliation as printed

   Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Gothenburg, Sweden