Cotunneling in pairs of coupled flux qubits
Abstract
We report measurements of macroscopic resonant tunneling between the two lowest energy states of a pair of magnetically coupled rfsuperconducting quantum interference device flux qubits. This technique provides both a direct means of measuring the energy gap of the twoqubit system and a method for probing of the environment coupled to the pair of qubits. Measurements of the tunneling rate as a function of qubit flux bias show a Gaussian line shape that is well matched to theoretical predictions. Moreover, the peak widths indicate that each qubit is coupled to a local environment whose fluctuations are uncorrelated with that of the other qubit.
 Publication:

Physical Review B
 Pub Date:
 August 2010
 DOI:
 10.1103/PhysRevB.82.060512
 arXiv:
 arXiv:1006.0028
 Bibcode:
 2010PhRvB..82f0512L
 Keywords:

 85.25.Dq;
 03.65.Xp;
 03.67.Lx;
 Superconducting quantum interference devices;
 Tunneling traversal time quantum Zeno dynamics;
 Quantum computation;
 Condensed Matter  Superconductivity
 EPrint:
 4 pages, 5 figures