Formation dynamics of an entangled photon pair -- a temperature dependent analysis

Abstract

We theoretically study the polarization entanglement of photons generated by the biexciton cascade in a GaAs/InAs semiconductor quantum dot (QD), located in a nano cavity. A detailed analysis of the complex interplay between photon- and carrier coherences and phonons which occurs during the cascade allows us to clearly identify where the entanglement is generated and destroyed. A quantum state tomography is performed for varying exciton fine structure splittings. By constructing an effective multi-phonon Hamiltonian which couples the continuum of the wetting layer states to the QD we investigate the relaxation of the biexciton and exciton states. This consistently introduces a temperature dependence to the cascade. Considering typical Stranski-Karastanov grown QDs, for temperatures around 80 K the degree of entanglement starts to be affected by the dephasing of the exciton states and is ultimately lost above 120 K.

14 pages, 10 figures, 1 table, submitted to phys. rev. B

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• From strong to weak temperature dependence of the two-photon entanglement resulting from the biexciton cascade inside a cavity
• Entanglement swapping with energy-polarization entangled photons from quantum dot cascade decay
• Stabilization of collapse and revival dynamics by a non-Markovian phonon bath
• Temperature-independent almost perfect photon entanglement from quantum dots via the SUPER scheme
• Entanglement Dynamics of Molecular Exciton States in Coupled Quantum Dots
• Highly entangled-photon pairs generated from the biexciton cascade transition in a quantum dot-metal nanoparticle hybrid system
• Entanglement robustness to excitonic spin precession in a quantum dot
• Photon Number Coherence in Quantum Dot-Cavity Systems can be Enhanced by Phonons