Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 11: Superconductivity: Poster

TT 11.50: Poster

Montag, 17. März 2025, 15:00–18:00, P4

Superconducting Qubits for Measurements with Infrared Photons — •Jonathan Huschle¹, Markus Griedel^1,2, Hannes Rotzinger^1,2, and Alexey V. Ustinov^1,2 — ¹Physikalisches Institut (PHI), Karlsruhe Institut for Technology (KIT) — ²Institut for Quanten Materials and Technologies (IQMT), Karlsruhe Institut for Technology (KIT)

In superconductors, the impact of photons with energy higher than the energy gap leads to breaking of Cooper pairs, which increases noise level and introduces additional dissipation at microwave frequencies. The coherence of superconducting qubits is particularly sensitive to this influence and can be used as a detector. In the qBriqs project, we develop a setup and measurement protocol for far-infrared photons and identify the influence of broken Cooper pairs using a modified transmon qubit[1]. Here, the capacitance of the qubit is reduced, resulting in an increased charge noise sensitivity. We present the qubit design and measurements at mK temperatures.

[1] B. G. Christensen et al., Phys. Rev. B 100, 140503 (2019).

Keywords: infrared radiation; quantum circuits; superconducting qubits; Josephson junctions; quasiparticles