Theory of microwave spectroscopy of Andreev bound states with a Josephson junction

L Bretheau (1) , C Ö Girit (1) , M Houzet (2) , H Pothier (1) , D Esteve (1) , C Urbina (1)

1 QUANTRONICS - Quantronics Group
2 GT - Laboratory of Quantum Theory

We present a microscopic theory for the current through a tunnel Josephson junction coupled to a non-linear environment, which consists of an Andreev two-level system coupled to a harmonic oscillator. It models a recent experiment [Bretheau, Girit, Pothier, Esteve, and Urbina, Nature 499, 312 (2013)] on photon spectroscopy of Andreev bound states in a superconducting atomic-size contact. We find the eigenenergies and eigenstates of the environment and derive the current through the junction due to inelastic Cooper pair tunneling. The current-voltage characteristic reveals the transitions between the Andreev bound states, the excitation of the harmonic mode that hybridizes with the Andreev bound states, as well as multi-photon processes. The calculated spectra are in fair agreement with the experimental data.

Domaines: Physique [physics]

L Bretheau, C Ö Girit, M Houzet, H Pothier, D Esteve, et al.. Theory of microwave spectroscopy of Andreev bound states with a Josephson junction. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 90 (13), pp.134506. ⟨10.1103/PhysRevB.90.134506⟩. ⟨cea-01384746⟩