Effects of charge noise on a pulse-gated singlet-triplet S−T− qubit

Qi, Zhenyi and Wu, X. and Ward, D. R. and Prance, Jonathan Robert and Kim, Dohun and Gamble, John King and Mohr, R. T. and Shi, Zhan and Savage, D. E. and Lagally, M. G. and Eriksson, M. A. and Friesen, Mark and Coppersmith, S. N. and Vavilov, M. G. (2017) Effects of charge noise on a pulse-gated singlet-triplet S−T− qubit. Physical review B, 96 (11): 115305. ISSN 2469-9950

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We study the dynamics of a pulse-gated semiconductor double-quantum-dot qubit. In our experiments, the qubit coherence times are relatively long, but the visibility of the quantum oscillations is low. We show that these observations are consistent with a theory that incorporates decoherence arising from charge noise that gives rise to detuning fluctuations of the double dot. Because effects from charge noise are largest near the singlet-triplet avoided level crossing, the visibility of the oscillations is low when the singlet-triplet avoided level crossing occurs in the vicinity of the charge degeneracy point crossed during the manipulation, but there is only modest dephasing at the large detuning value at which the quantum phase accumulates. This theory agrees well with experimental data and predicts that the visibility can be increased greatly by appropriate tuning of the interdot tunneling rate.

Item Type:
Journal Article
Journal or Publication Title:
Physical review B
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©2017 American Physical Society
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Deposited On:
20 Sep 2017 13:06
Last Modified:
15 Jul 2024 17:12