Decoherence of Flux Qubits due to 1/f Flux Noise

作者：Fumiki Yoshihara, K. Harrabi, A. O. Niskanen, Yasunobu Nakamura, Jaw-Shen Tsai · 发表于：Physical Review Letters · 年份：2006 · DOI：10.1103/physrevlett.97.167001 · 被引用次数：400 · 研究领域：Quantum Computing Algorithms and Architecture、Quantum Information and Cryptography、Quantum and electron transport phenomena

We have investigated decoherence in Josephson-junction flux qubits. Based on the measurements of decoherence at various bias conditions, we discriminate contributions of different noise sources. We present a Gaussian decay function extracted from the echo signal as evidence of dephasing due to 1/f flux noise whose spectral density is evaluated to be about (10(-6)Phi0)2/Hz at 1 Hz. We also demonstrate that, at an optimal bias condition where the noise sources are well decoupled, the coherence observed in the echo measurement is limited mainly by energy relaxation of the qubit.