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arXiv · 2406.11383

Coherence of an Electronic Two-Level System under Continuous Charge Sensing by a Quantum Dot Detector

Subhomoy Haldar·Morten Munk·Harald Havir·Waqar Khan·Sebastian Lehmann·Claes Thelander·Kimberly A. Dick·Peter Samuelsson·Patrick P. Potts·Ville F. Maisi
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Abstract

We investigate experimentally the quantum coherence of an electronic two-level system in a double quantum dot under continuous charge detection. The charge-state of the two-level system is monitored by a capacitively coupled single quantum dot detector that imposes a back-action effect to the system. The measured back-action is well described by an additional decoherence rate, approximately linearly proportional to the detector electron tunneling rate. We provide a model for the decoherence rate arising due to level detuning fluctuations induced by detector charge fluctuations. The theory predicts a factor of two lower decoherence rate than observed in the experiment, suggesting the need for a more elaborate theory accounting for additional sources of decoherence.

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Subhomoy Haldar, Morten Munk, Harald Havir, Waqar Khan, Sebastian Lehmann, Claes Thelander, Kimberly A. Dick, Peter Samuelsson, Patrick P. Potts, Ville F. Maisi. 2024-06-17. Coherence of an Electronic Two-Level System under Continuous Charge Sensing by a Quantum Dot Detector. https://doi.org/10.1103/physrevlett.134.023601

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