Quantum control of driven artificial atoms

M. J. SANCHEZ; A. FERRÓN; D. DOMINGUEZ

Aspen

Workshop; Worskshop on Quantum control of many body systems,; 2016

Weakly disordered electronic mesoscopic systems exhibit, at milikelvin temperatures, fingerprints of phase coherence. Among others phenomena, weak localization and universal conductance fluc- tuations have been studied for years. Here we investigate similar effects in flux qubits driven by a biharmonic magnetic signal with a phase lag, profit from a direct analogy between interference effects at avoided level crossings and scattering events in disordered mesoscopic systems. The tran- sition rate between the ground and the excited state of the flux qubit plays 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, weak localization and conductance fluctuations-like effects, whose behavior is compared to models that account for decoherence solely as a classical noise.We show that it is decoherence -and not the driving protocol as previous interpretations suggest- what limits the experimental detection of weak localization effects. Our study goes beyond the two level system case, and might result valuable for ongoingexperiments with artificial atoms in the strong driving regime.