Generating Two Continuous Entangled Microwave Beams Using a dc-Biased Josephson Junction
Journal article, 2021
We show experimentally that a dc-biased Josephson junction in series with two microwave resonators emits entangled beams of microwaves leaking out of the resonators. In the absence of a stationary phase reference for characterizing the entanglement of the outgoing beams, we measure second-order coherence functions to prove the entanglement. The experimental results are found in quantitative agreement with theory, proving that the low-frequency noise of the dc bias is the main limitation for the coherence time of the entangled beams. This agreement allows us to evaluate the entropy of entanglement of the resonators, estimate the entanglement flux at their output, and to identify the improvements that could bring this device closer to a useful bright source of entangled microwaves for quantum-technological applications.
Superconductivity
Quantum Physics
Mesoscopics
Author
A. Peugeot
University Paris-Saclay
G. Menard
University Paris-Saclay
S. Dambach
University of Ulm
M. Westig
University Paris-Saclay
B. Kubala
German Aerospace Center (DLR)
University of Ulm
Y. Mukharsky
University Paris-Saclay
C. Altimiras
University Paris-Saclay
P. Joyez
University Paris-Saclay
D. Vion
University Paris-Saclay
P. Roche
University Paris-Saclay
D. Esteve
University Paris-Saclay
P. Milman
Paris Descartes University
J. Leppaekangas
Karlsruhe Institute of Technology (KIT)
Göran Johansson
Chalmers, Microtechnology and Nanoscience (MC2), Applied Quantum Physics
M. Hofheinz
Université de Sherbrooke
J. Ankerhold
University of Ulm
F. Portier
University Paris-Saclay
Physical Review X
21603308 (eISSN)
Vol. 11 3 031008Subject Categories
Accelerator Physics and Instrumentation
Atom and Molecular Physics and Optics
Other Physics Topics
DOI
10.1103/PhysRevX.11.031008