Arising from: R. M. Stevenson et al. Nature 439, 179–182 (2006); Stevenson et al. reply

The realization of an entangled photon source will be of great importance in quantum information — for example, for quantum key distribution and quantum computation — and Stevenson et al.¹ have described such a source. However, we show here that first, their source is not entangled; second, they use inappropriate entanglement indicators that rely on assumptions invalidated by their data; and third, their source has insignificant entanglement even after simulating subtraction of the significant quantity of background noise. We therefore find that the standard of proof required for a semiconductor source of triggered entangled photon pairs has not been met by Stevenson et al.¹.

1. Department of Physics and Centre for Quantum Computer Technology, University of Queensland, Brisbane, Queensland 4072, Australia
2. Present address: Department of Physics and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada

Correspondence to: Andrew G. White¹ Email: andrew.white@physics.uq.edu.au

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