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.


Quantum Physics



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 031008

Subject Categories

Accelerator Physics and Instrumentation

Atom and Molecular Physics and Optics

Other Physics Topics



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8/3/2021 9