Switchable resonant coupling of flux qubits

M. Grajcar, Yu-xi Liu, Franco Nori, A. M. Zagoskin
2006 Physical Review B  
We propose a coupling scheme, where two or more flux qubits with different eigenfrequencies share Josephson junctions with a coupler loop devoid of its own quantum dynamics. Switchable two-qubit coupling is realized by tuning the frequency of the AC magnetic flux through the coupler to a combination frequency of two of the qubits. The coupling allows any or all of the qubits to be simultaneously at the degeneracy point and can change sign.
doi:10.1103/physrevb.74.172505 fatcat:oiqxjwevmbhd5psma6yasoeu4q