Entanglement robustness to excitonic spin precession in a quantum dot
| Autor: | Kisa Barkemeyer, André Strittmatter, Andreas Knorr, Jan-Hindrik Schulze, Manuel Gschrey, Sven Rodt, Stephan Reitzenstein, Gabriel Rein, S. Bounouar, Peter Schnauber, Alexander Carmele, Julian Schleibner |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Quantum Physics Photon Condensed Matter - Mesoscale and Nanoscale Physics FOS: Physical sciences 02 engineering and technology Quantum entanglement Quantum tomography Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences Quantum dot Quantum mechanics Temporal resolution Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Precession Radiative transfer Quantum Physics (quant-ph) 010306 general physics 0210 nano-technology Spin-½ |
| Zdroj: | Physical Review B. 102 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | A semiconductor quantum dot (QD) is an attractive resource to generate polarization-entangled photon pairs. We study the excitonic spin precession (flip-flop) in a family of QDs with different excitonic fine-structure splitting (FSS) and its impact on the entanglement of photons generated from the excitonic-biexcitonic radiative cascade. Our results reveal that coherent processes leave the time postselected entanglement of QDs with finite FSS unaffected while changing the eigenstates of the system. The flip-flop's precession is observed via quantum tomography through anomalous oscillations of the coincidences in the rectilinear basis. A theoretical model is constructed with the inclusion of an excitonic flip-flop rate and is compared with a two-photon quantum tomography measurement on a QD exhibiting the spin flip-flop mechanism. A generalization of the theoretical model allows estimating the degree of entanglement as a function of the FSS and the spin precession rate. For a finite temporal resolution, the negativity is found to be oscillating with respect to both the FSS and the spin precession rate. This oscillatory behavior disappears for perfect temporal resolution and maximal entanglement is retrieved despite the flip-flop process. |
| Databáze: | OpenAIRE |
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