0
0.2
0.4
0.6
0.8
1
0
2
4
6
8
10
f01
f02
f12
sweet spot: f01 = 529 MHz
half flux quantum
external flux Phi_ext / Phi0
transition frequency (GHz)
Fluxonium spectrum from exact diagonalization (EC=1.05, EL=0.95, EJ=4.20 GHz)
f01
f02
f12