title: Dressed-state amplification by a single superconducting qubit.
abstract: We demonstrate amplification of a microwave signal by a strongly driven two-level system in a coplanar waveguide resonator. The effect, similar to the dressed-state lasing known from quantum optics, is observed with a single quantum system formed by a persistent current (flux) qubit. The transmission through the resonator is enhanced when the Rabi frequency of the driven qubit is tuned into resonance with one of the resonator modes. Amplification as well as linewidth narrowing of a weak probe signal has been observed. The stimulated emission in the resonator has been studied by measuring the emission spectrum. We analyzed our system and found an excellent agreement between the experimental results and the theoretical predictions obtained in the dressed-state model.
authors: Institute of Photonic Technology, P.O. Box 100239, D-07702 Jena, Germany.
authors: G
authors: G
authors: Oelsner
authors: P
authors: P
authors: Macha
authors: O V
authors: OV
authors: Astafiev
authors: E
authors: E
authors: Il'ichev
authors: M
authors: M
authors: Grajcar
authors: U
authors: U
authors: Hübner
authors: B I
authors: BI
authors: Ivanov
authors: P
authors: P
authors: Neilinger
authors: H-G
authors: HG
authors: Meyer