Dynamic transition in Landau-Zener-Stuckelberg interferometry of dissipative systems: The case of the flux qubit

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

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2016 vol. 93 p. 64521 - 6452116

1098-0121

We study Landau-Zener-Stuckelberg (LZS) interferometry in multilevel systems coupled to an Ohmic quantumbath. We consider the case of superconducting flux qubits driven by a dc+ac magnetic fields, but our results canapply to other similar systems. We find a dynamic transition manifested by a symmetry change in the structureof the LZS interference pattern, plotted as a function of ac amplitude and dc detuning. The dynamic transitionis from an LZS pattern with nearly symmetric multiphoton resonances to antisymmetric multiphoton resonancesat long times (above the relaxation time). We also show that the presence of a resonant mode in the quantumbath can impede the dynamic transition when the resonant frequency is of the order of the qubit gap. Our resultsare obtained by a numerical calculation of the finite time and the asymptotic stationary population of the qubitstates, using the Floquet-Markov approach to solve a realistic model of the flux qubit considering up to ten energylevels.