Spectrum of Andreev Bound States in a Molecule Embedded Inside a Microwave-Excited Superconducting Junction
KTH/Nordita/SU seminar in Theoretical Physics [before December 2013]
Wednesday 02 March 2011
to 12:00 at
Mikael Fogelström (Chalmers)
Nondissipative Josephson current through nanoscale superconducting constrictions is carried by
spectroscopically sharp energy states, the so-called Andreev 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.