# Measurements of Decoherence Times in a Josephson Charge Qubit Using Fast Pulses

Research paper by T. Duty, K. Bladh, D. Gunnarsson, P. Delsing

Indexed on: 01 Sep '04Published on: 01 Sep '04Published in: Journal of low temperature physics

#### Abstract

We study decoherence of a Josephson charge qubit using fast pulses to perform qubit rotations. The gate charge dependence of the decoherence rate indicates that the low frequency fluctuations affecting the qubit are from charges distributed with a 1/f-type spectrum. Assuming the form Sq(ω) = α/|ω|, we find $$\sqrt \alpha$$ = 4 × 10−3e, which is slightly higher than the value found from very low frequency noise measurements. PACS numbers: 03.67.-a, 75.40.+r, 85.25.Cp.