Continuous Impedance measurement of a Superconducting Flux Qubit

Wei Qiu, Bo Mao, Yang Yu +2 more

Thomas Picot

P. A. Reichardt, T. Hime, B. L. T. Plourde +3 more

C.-E. Wu, T. Hime, B. L. T. Plourde +3 more

А. S. Kiyko, A. N. Omelyanchouk, Sergey N Shevchenko

We study theoretically the behavior of a superconducting flux qubit subjected to a series of electromagnetic pulses. The possibility of controlling the system state via changing the parameters of the pulse is studied. We calculated the phase shift in the tank circuit weakly coupled to the qubit which can be measured by the impedance measurement technique. For the flux qubit we consider the possibility of estimating the relaxation rate from the impedance measurements by varying the delay time between the pulses.

Ji Ying

We derive Bloch-Redfield function with flux biased superconducting circuit in the framework classical circuit theory.Under two-level approximation,we discuss the influence of the different environment impedancses and the coupling strength on the decoherence of the magnetic flux qubit.We find that: under certain condition,the decoherence time decreases as the coupling strength increases,and when the environment impedance is pure impedance,the decoherence time increases as the impedance increases while the environment impedance consists of the resistor and capacitor,the influence of the different circuit elements on the decoherence time is different.