Spectral signature of high-order photon processes enhanced by Cooper-pair pairing

W. C. Smith (), A. Borgognoni, M. Villiers, E. Roverc’h, J. Palomo, M. R. Delbecq, T. Kontos, P. Campagne-Ibarcq, B. Douçot and Z. Leghtas ()
Additional contact information
W. C. Smith: Université PSL, Inria
A. Borgognoni: Université PSL, Inria
M. Villiers: Université PSL, Inria
E. Roverc’h: Université PSL, Inria
J. Palomo: Université PSL, Inria
M. R. Delbecq: Université PSL, Inria
T. Kontos: Université PSL, Inria
P. Campagne-Ibarcq: Université PSL, Inria
B. Douçot: Sorbonne Université and CNRS UMR 7589
Z. Leghtas: Université PSL, Inria

Nature Communications, 2025, vol. 16, issue 1, 1-8

Abstract: Abstract Inducing interactions between individual photons is key for photonic quantum information and studying many-body photon states. Superconducting circuits are well suited to combine strong interactions with low losses. Typically, microwave photons are stored in an LC oscillator shunted by a Josephson junction, where the zero-point phase fluctuations across the junction determine the strength and order of photon interactions. Most superconducting nonlinear oscillators operate with small phase fluctuations, where two-photon Kerr interactions dominate. In our experiment, we shunt a high-impedance LC oscillator with a dipole element favoring the tunneling of paired Cooper pairs. This leads to large phase fluctuations of 3.4, accessing a regime where transition frequencies shift non-monotonically with excitation number. From spectroscopy, we extract two-, three-, and four-photon interaction energies, all of similar strength and exceeding the photon loss rate. Our results open a new regime of high-order photon interactions in microwave quantum optics.

Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41467-025-62047-8 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:16:y:2025:i:1:d:10.1038_s41467-025-62047-8

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-025-62047-8

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().