Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 42: Superconductivity: Tunneling and Josephson Junctions
TT 42.11: Vortrag
Donnerstag, 20. März 2025, 12:15–12:30, H32
Amplification Schemes for Single Microwave Photons — •Lukas Danner1, 2, Hanna Zeller2, Ciprian Padurariu2, Joachim Ankerhold2, and Björn Kubala1, 2 — 1Institute for Quantum Technologies, German Aerospace Center (DLR), Ulm (Germany) — 2Institute for Complex Quantum Systems and IQST, University of Ulm, Ulm (Germany)
The detection of single microwave photons plays a crucial role in a wide range of envisioned technological applications of quantum microwaves. However, this is challenging because of the large thermal background and the low energy of a single photon.
Here, we investigate schemes to amplify single itinerant mircowave photons using Josephson photonics devices [1, 2]. These devices consist of a dc-voltage biased Josephson junction, connected in series with two microwave cavities. By tuning the dc voltage, various resonances can easily be accessed, such that e.g. a Cooper pair tunneling through the junction enables a coherent transfer between one excitation in the first cavity and n excitations in the second cavity. We show that a single photon pulse absorbed by the device effectively triggers the emission of multiple photons from the second cavity that can subsequently be detected. To study such processes theoretically, we use a recently developed formalism [3] to describe arbitrary traveling photon pulses interacting with a quantum system in a cascaded manner.
[1] Leppäkangas et al., Phys. Rev. A 97, 013855 (2018)
[2] Albert et al., Phys. Rev. X, 14, 011011 (2024)
[3] Kiilerich and Mølmer, Phys. Rev. Lett. 123, 123604 (2019)
Keywords: quantum microwaves; photon amplification; superconducting devices; mesoscopic systems