Correlated Cooper pair transport and microwave photon emission in the dynamical Coulomb blockade

Understand

We study theoretically electromagnetic radiation emitted by inelastic Cooper-pair tunneling.

• We consider a dc-voltage-biased superconducting transmission line terminated by a Josephson junction.
• We show that the generated continuous-mode electromagnetic field can be expressed as a function of the time-dependent current across the Josephson junction.
• The leading-order expansion in the tunneling coupling, similar to the "$P(E)$-theory", has previously been used to investigate the photon emission statistics in the limit of sequential (independent) Cooper-pair tunneling.