Weak localization and conductance fluctuations-like effects in Qubits driven by biharmonic signals

FERRON, ALEJANDRO; DANIEL DOMINGUEZ; MARIA JOSE SANCHEZ

Buenos Aires

Workshop; 27th International Conference on Low Temperature Physics (LT27); 2014

We investigate the eect of broken time reversal symmetry in ux qubits driven by abiharmonic magnetic ux signal with a phase lag. In the regime of large relaxation times,we explicitly compute the transition rate between the ground and the excited state, accountingfor decoherence as a classical noise. Through a direct analogy between interference eects at theavoided level crossing and scattering events in weakly disordered electronic mesoscopic systems,the transition rate plays the role of an eective transmittance while the phase lag acts as atime reversal control parameter. Clear signatures of both weak localization and conductance uctuations-like eects are predicted. Their behavior is studied as a function of the coherencerate, and a comparison with recent experimental results is performed. Our study shows thatit is decoherence, and not the driving protocol, what limits the experimental detection of weaklocalization eects.