Quantum noise in the josephson charge qubit.
We study decoherence of the Josephson charge qubit by measuring energy relaxation and dephasing with help of the single-shot readout. We found that the dominant energy relaxation process is a spontaneous emission induced by quantum noise coupled to the charge degree of freedom. Spectral density of the noise at high frequencies is roughly proportional to the qubit excitation energy.
Astafiev
O
O
The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198, Japan. astf@frl.cl.nec.co.jp
Pashkin
Yu A
YA
Nakamura
Y
Y
Yamamoto
T
T
Tsai
J S
JS