Nature Photonics 4, 302–306 (2010); published online: 7 March 2010; retracted online: 16 October 2012.

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.