Zusammenfassung
We realize a $Łambda$ system in a superconducting circuit, with metastable
states exhibiting lifetimes up to 7ms. We exponentially suppress the tunneling
matrix elements involved in spontaneous energy relaxation by creating a "heavy"
fluxonium, realized by adding a capacitive shunt to the original circuit
design. The device allows for both cavity-assisted and direct fluorescent
readout, as well as state preparation schemes akin to optical pumping. Since
direct transitions between the metastable states are strongly suppressed, we
utilize Raman transitions for coherent manipulation of the states.
Nutzer