Spectral signature of high-order photon processes mediated by Cooper-pair pairing - Inria - Institut national de recherche en sciences et technologies du numérique Access content directly
Preprints, Working Papers, ... (Preprint) Year : 2023

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


Inducing interactions between individual photons is essential for applications in photonic quantum information processing and fundamental research on many-body photon states. A field that is well suited to combine strong interactions and low losses is microwave quantum optics with superconducting circuits. Photons are typically stored in an $LC$ circuit, and interactions appear when the circuit is shunted by a Josephson tunnel junction. Importantly, the zero-point fluctuations of the superconducting phase across the junction control the strength and order of the induced interactions. Superconducting circuits have almost exclusively operated in the regime where phase fluctuations are smaller than unity, and two-photon interactions, known as the Kerr effect, dominate. In this experiment, we shunt a high-impedance $LC$ oscillator by a dipole that only allows pairs of Cooper pairs to tunnel. Phase fluctuations, which are effectively doubled by this pairing, reach the value of 3.4. In this regime of extreme fluctuations, we observe transition frequencies that shift non-monotonically as we climb the anharmonic ladder. From this spectroscopic measurement, we extract two-, three- and four-photon interaction energies of comparable amplitude, and all exceeding the photon loss rate. This work explores a new regime of high-order photon interactions in microwave quantum optics, with applications ranging from multi-photon quantum logic to the study of highly correlated microwave radiation.
Fichier principal
Vignette du fichier
2312.15075.pdf (3.88 Mo) Télécharger le fichier
Origin Files produced by the author(s)

Dates and versions

hal-04387016 , version 1 (11-01-2024)



William C Smith, Alvise Borgognoni, Marius Villiers, Erwan Roverc'H, José Palomo, et al.. Spectral signature of high-order photon processes mediated by Cooper-pair pairing. 2023. ⟨hal-04387016⟩
47 View
7 Download



Gmail Mastodon Facebook X LinkedIn More