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arXiv · 0801.3608

Spectrum of Andreev Bound States in a Molecule Embedded Inside a Microwave-Excited Superconducting Junction

Jonas Skoldberg·Tomas Lofwander·Vitaly S. Shumeiko·Mikael Fogelstrom
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Abstract

Non-dissipative Josephson current through nanoscale superconducting constrictions is carried by spectroscopically sharp energy states, so-called Andreev bound states. Although theoretically predicted almost 40 years ago, no direct spectroscopic evidence of these Andreev bound states exists to date. We propose a novel type of spectroscopy based on embedding a superconducting constriction, formed by a single-level molecule junction, in a microwave QED cavity environment. In the electron-dressed cavity spectrum we find a polariton excitation at twice the Andreev bound state energy, and a superconducting-phase dependent ac Stark shift of the cavity frequency. Dispersive measurement of this frequency shift can be used for Andreev bound state spectroscopy.

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Jonas Skoldberg, Tomas Lofwander, Vitaly S. Shumeiko, Mikael Fogelstrom. 2008-09-15. Spectrum of Andreev Bound States in a Molecule Embedded Inside a Microwave-Excited Superconducting Junction. https://doi.org/10.1103/physrevlett.101.087002

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