To verify the hypothesis about the common origin of the low-frequency 1/f noise and the quantum f noise recently measured in the Josephson charge qubits, we study the temperature dependence of the 1/f noise and decay of coherent oscillations. The T2 dependence of the 1/f noise is experimentally demonstrated, which supports the hypothesis. We also show that dephasing in the Josephson charge qubits off the electrostatic energy degeneracy point is consistently explained by the same low-frequency 1/f noise that is observed in the transport measurements.To verify the hypothesis about the common origin of the low-frequency 1/f noise and the quantum f noise recently measured in the Josephson charge qubits, we study the temperature dependence of the 1/f noise and decay of coherent oscillations. The T2 dependence of the 1/f noise is experimentally demonstrated, which supports the hypothesis. We also show that dephasing in the Josephson charge qubits off the electrostatic energy degeneracy point is consistently explained by the same low-frequency 1/f noise that is observed in the transport measurements.

arXiv:cond-mat/0604116Physical Review LettersApr 4, 200676 citations

1/F Noise During Manipulation of Josephson Charge Qubits

Elisabetta Paladino, Lara Faoro, G. Falci +1 more

Springer eBooksJan 1, 20012 citations

Measuring charge and flux noise correlations with a superconducting qubit

Bradley Christensen, Christopher D. Wilen, Alexander Opremcak +7 more

Bulletin of the American Physical SocietyMar 6, 20190 citations

Effect of Two Level System Saturation on Charge Noise in Josephson Junction Qubits

Clare C. Yu, Constantin, Magdalena, John M. Martinis

We show that charge noise $S_Q$ in Josephson qubits can be produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate using a flat density of states. At high frequencies the frequency and temperature dependence of the charge noise depends on the ratio $J/J_c$ of the electromagnetic flux $J$ to the critical flux $J_c$ . It is not widely appreciated that TLS in small qubits can easily be strongly saturated with $J/J_c\gg 1$ . Our results are consistent with experimental conclusions that $S_Q\sim 1/f$ at low frequencies and $S_Q\sim f$ at high frequencies.We show that charge noise $S_Q$ in Josephson qubits can be produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate using a flat density of states. At high frequencies the frequency and temperature dependence of the charge noise depends on the ratio $J/J_c$ of the electromagnetic flux $J$ to the critical flux $J_c$. It is not widely appreciated that TLS in small qubits can easily be strongly saturated with $J/J_c\gg 1$. Our results are consistent with experimental conclusions that $S_Q\sim 1/f$ at low frequencies and $S_Q\sim f$ at high frequencies.

arXiv:0707.1514Jul 10, 20071 citation

Short-time decoherence of Josephson charge qubits

Xian-Ting Liang, Yong-Jian Xiong

arXiv:quant-ph/0405188Physica B Condensed MatterApr 4, 20058 citations

We show that charge noise

S_Q

in Josephson qubits can be produced by fluctuating two level systems (TLS) with electric dipole moments in the substrate using a flat density of states. At high frequencies the frequency and temperature dependence of the charge noise depends on the ratio

J/J_c

of the electromagnetic flux

J

to the critical flux

J_c

. It is not widely appreciated that TLS in small qubits can easily be strongly saturated with

J/J_c\gg 1

. Our results are consistent with experimental conclusions that

S_Q\sim 1/f

at low frequencies and

S_Q\sim f

at high frequencies.