title: Microwave down-conversion with an impedance-matched Λ system in driven circuit QED.
abstract: By driving a dispersively coupled qubit-resonator system, we realize an "impedance-matched" Λ system that has two identical radiative decay rates from the top level and interacts with a semi-infinite waveguide. It has been predicted that a photon input from the waveguide deterministically induces a Raman transition in the system and switches its electronic state. We confirm this through microwave response to a continuous probe field, observing near-perfect (99.7%) extinction of the reflection and highly efficient (74%) frequency down-conversion. These proof-of-principle results lead to deterministic quantum gates between material qubits and microwave photons and open the possibility for scalable quantum networks interconnected with waveguide photons.
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Inomata
authors.affiliation: College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Koshino
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
authors.forename: Z R
authors.initials: ZR
authors.lastname: Lin
authors.affiliation: MIT Lincoln Laboratory, 244 Wood Street, Lexington, Massachusetts 02420, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Oliver
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan and NEC Smart Energy Research Laboratories, Tsukuba, Ibaraki 305-8501, Japan.
authors.forename: J S
authors.initials: JS
authors.lastname: Tsai
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan and Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan and NEC Smart Energy Research Laboratories, Tsukuba, Ibaraki 305-8501, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto