Mesoscopic fluctuations in the interferometry of driven flux qubits

A. FERRÓN, D. DOMINGUEZ AND M. J. SANCHEZ

GOTHEMBURGO

Conferencia; LT28, CONFERENCE ON LOW TEMPERATURE PHYSICS; 2017

pre { direction: ltr; color: rgb(0, 0, 0); }pre.western { }pre.cjk { font-family: "Droid Sans Fallback",monospace; }pre.ctl { }p { margin-bottom: 0.08in; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: "Times New Roman",serif; font-size: 12pt; }p.cjk { font-family: "DejaVu Sans"; font-size: 12pt; }p.ctl { font-family: "DejaVu Sans"; font-size: 12pt; }Disordered electronic mesoscopicsystems exhibit, at milikelvintemperatures, fingerprints of phase coherence. Among othersphenomena, weak localization and universal conductance fluctuationshave been studied for years.Here we investigate similar effects in flux qubitsdriven by a biharmonic magnetic signal with a phase lag, profitfrom a direct analogy between interference effects at avoided levelcrossings and scattering events in disordered mesoscopicsystems. The transition rate between the ground and the excited state of the flux qubitplays the role of an effective transmitance,while the phase lag acts as a time reversal control parameter. Using the Floquet Markov Master equation we predict clear signatures of both, weaklocalization and conductance fluctuations-like effects, whosebehavior is compared to models that account for decoherencesolely as a classical noise. Our study might result valuable for experiments with artificial atoms in the strong drivingregime.