Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 10: Focus Session: New Bright Sources of Quantum Microwaves
TT 10.3: Invited Talk
Monday, April 1, 2019, 16:00–16:30, H2
Quantum microwaves with a DC-biased Josephson junction — Fabien Portier1, Ambroise Peugeot1, Chloé Rolland1, Marc Westig1, Gerbold Ménard1, Yuri Mukharsky1, Hélène le Sueur1, Patrice Roche1, Philippe Joyez1, •Carles Altimiras1, Patrice Bertet1, Daniel Esteve1, Denis Vion1, Max Hofheinz1, Pérola Milman2, Bjoern Kubala3, Simon Dambach3, and Joachim Ankerhold3 — 1SPEC (UMR 3680 CEA-CNRS), CEA Paris-Saclay, 91191 Gif-sur-Yvette, France — 2LMPQ, Université Paris Diderot, CNRS UMR 7162, 75013, Paris, France — 3ICQS and IQST, University of Ulm, 89069 Ulm, Germany
Tunneling of a Cooper pair through a dc-biased Josephson junction is possible only if collective excitations (photons) are produced in the rest of the circuit to conserve the energy. The probability of tunneling and photon creation, well described by the theory of dynamical Coulomb blockade, increases with the coupling strength between the tunneling charge and the circuit mode, which scales as the mode impedance. Using very simple circuits with only one or two high impedance series resonators, we first show the equality between Cooper pair tunneling rate and photon production rate. Then we demonstrate a blockade regime for which the presence of a single photon blocks the next tunneling event and the creation of a second photon. Finally, using two resonator with different frequencies, we demonstrate photon pair production, two-mode squeezing, and entanglement between the two modes leaking out of the resonators.