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arXiv · 1203.2233

Non-Markovian dynamics and noise characteristics in continuous measurement of a solid-state charge qubit

JunYan Luo·HuJun Jiao·Xiao-Li Lang·BiTao Xiong·Xiao-Ling He
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Abstract

We investigate the non-Markovian characteristics in continuous measurement of a charge qubit by a quantum point contact. The backflow of information from the reservoir to the system in the non-Markovian domain gives rise to strikingly different qubit relaxation and dephasing in comparison with the Markovian case. The intriguing non-Markovian dynamics is found to have a direct impact on the output noise feature of the detector. Unambiguously, we observe that the non-Markovian memory effect results in an enhancement of the signal-to-noise ratio, which can even exceed the upper limit of ``4'', leading thus to the violation of the Korotkov-Averin bound in quantum measurement. Our study thus may open new possibilities to improve detector's measurement efficiency in a direct and transparent way.

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JunYan Luo, HuJun Jiao, Xiao-Li Lang, BiTao Xiong, Xiao-Ling He. 2012-03-10. Non-Markovian dynamics and noise characteristics in continuous measurement of a solid-state charge qubit. https://doi.org/10.1063/1.4828870

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