Correction: Retraction: Polarization-entangled photons produced with high-symmetry site-controlled quantum dots

Abstract

In this Letter, we claimed the generation of entangled photons from highly symmetric site-controlled pyramidal quantum dots. Apart from the observation of isotropic emission and the measurement of a vanishing fine-structure splitting of 0 μeV ± 2 μeV , a fidelity of >0.5 was obtained by using the density matrix derived from quantum state tomography of 16 different polarization-resolved correlation measurements. After further investigation of the second-order correlation functions, g (2) ( τ ), major errors were found and the best fidelity found is now 0.45 for a gate width of 0.225 ns. As a result, we can no longer claim emission of polarization-entangled photons. We therefore wish to retract this Letter and sincerely apologize for any adverse consequence that may have resulted from the paper’s publication.