Dresden 2026 – scientific programme

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QI: Fachverband Quanteninformation

QI 11: Implementations IV

QI 11.1: Invited Talk

Wednesday, March 11, 2026, 09:30–10:00, BEY/0245

Nb-trilayer Josephson junction based parametric amplifiers for microwave frequency signals — •Lukas Grünhaupt — Physikalisch-Technische Bundesanstalt, Braunschweig, Germany

Parametric amplifiers have become a widely-used tool in cryogenic setups processing faint microwave signals. Such signals, with powers as low as femtowatts, are used, e.g., to read out solid state qubits or are hypothesized as signatures of dark matter. A large variety of superconducting parametric amplifiers exists, which can be broadly divided into two groups: devices based on resonators with typical bandwidth on the order of a few MHz and traveling-wave parametric amplifiers (TWPAs) providing bandwidths larger than 1 GHz. In addition to their bandwidth, dynamic range and added noise are the main parameters engineered in such devices, leading to a plethora of parametric amplifier implementations. At PTB we are exploring a range of superconducting parametric amplifiers harnessing the nonlinearity provided by Nb-trilayer Josephson junctions or by the kinetic inductance of granular aluminium thin films. In this talk I will discuss our recent results on rf-SQUID TWPAs [1] and present our implementation of dimer Josephson junction array amplifiers.

[1] V. Gaydamachenko & C. Kissling, L. Grünhaupt, Phys. Rev. Appl. 23, 064053 (2025)

Keywords: TWPA; parametric amplifier; standard quantum limit; microwave frequency; readout