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Accuracy of the Quantum Regression Theorem for Photon Emission from a Quantum Dot
M Cosacchi1, T Seidelmann1, M Cygorek2
1Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany.
Physical Review Letters
|September 17, 2021
Summary
The quantum regression theorem (QRT) overestimates environmental effects in quantum dots. This study quantifies its inaccuracies for quantum information technology applications.
Area of Science:
- Quantum optics
- Condensed matter physics
- Quantum information science
Background:
- The quantum regression theorem (QRT) is a standard approximation for calculating multitime correlation functions.
- It relies on a Markov assumption for environmental coupling, which may not hold for all quantum systems.
- Accurate characterization of quantum emitters is crucial for quantum technologies.
Purpose of the Study:
- To quantify the accuracy of the QRT for assessing quantum emitters.
- To compare QRT predictions with numerically exact results for photon properties.
- To evaluate the QRT's suitability for quantum dots used in quantum information technology.
Main Methods:
- Numerical simulation using path-integral methods for exact results.
- Application of the quantum regression theorem (QRT) for approximate calculations.
- Analysis of single-photon purity and indistinguishability for emitted photons.
Main Results:
- The QRT systematically overestimates the influence of environmental coupling.
- Deviations are significant for typical quantum dots relevant to quantum information.
- Path-integral results provide a benchmark for QRT accuracy.
Conclusions:
- The QRT's Markov approximation limits its applicability for certain quantum dot systems.
- Careful consideration of environmental coupling is needed when using QRT.
- Numerical exact methods are essential for precise characterization of quantum emitters.
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