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Coherence of an Electronic Two-Level System under Continuous Charge Sensing by a Quantum Dot Detector
Subhomoy Haldar1, Morten Munk2, Harald Havir1
1Lund University, NanoLund and Solid State Physics, Box 118, 22100 Lund, Sweden.
Physical Review Letters
|February 6, 2025
Summary
We studied quantum coherence in a double quantum dot using charge detection. Continuous monitoring caused decoherence, which was modeled but not fully explained by theory.
Area of Science:
- Quantum Computing
- Condensed Matter Physics
Background:
- Quantum coherence is crucial for quantum computing.
- Charge detection in quantum dots can disturb quantum systems.
Purpose of the Study:
- To experimentally investigate quantum coherence in a double quantum dot system.
- To understand the decoherence effects of continuous charge detection.
Main Methods:
- Utilized a capacitively coupled single quantum dot detector.
- Monitored the charge state of an electronic two-level system.
- Measured the backaction effect on quantum coherence.
Main Results:
- Continuous charge detection induced a decoherence rate.
- Decoherence rate correlated with detector electron tunneling rate.
- Experimental decoherence rates were twice the theoretical prediction.
Conclusions:
- Detector backaction significantly impacts quantum coherence.
- Current theoretical models do not fully capture observed decoherence.
- Further research is needed to explain additional decoherence sources.
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