Bell inequalities for polarization entangled photons out of a two-photon cascade in a single quantum dot

Matthieu Larqué (1) , Isabelle Robert-Philip (1) , Alexios Beveratos (1)

1 LPN - Laboratoire de photonique et de nanostructures

We theoretically investigate the conditions for Bell's inequalities violation by use of polarization-entangled photons from the biexciton radiative cascade in a semiconductor quantum dot. Our model includes different mechanisms that may spoil or even destroy entanglement such as dephasing, energy splitting of the relay excitonic states and incoherent population exchange between these relay levels. We explicitly relate the fidelity of entanglement to the dynamics of these processes and derive a threshold for violation of Bell's inequalities. Applied to standard InAs/GaAs self-assembled quantum dots, our model indicates that spontaneous emission enhancement of the excitonic states by cavity effects increases the fidelity of entanglement to a value allowing for violation of Bell's inequalities.

Domaines: Optique [physics.optics]; Physique Quantique [quant-ph]

Matthieu Larqué, Isabelle Robert-Philip, Alexios Beveratos. Bell inequalities for polarization entangled photons out of a two-photon cascade in a single quantum dot. 2008. ⟨hal-00213464v1⟩