We present an experimental realisation of Hardy's thought experiment [Phys. Rev. Lett. {\bf 68}, 2981 (1992)], using photons. The experiment consists of a pair of Mach-Zehnder interferometers that interact through photon bunching at a beam splitter. A striking contradiction is created between the predictions of quantum mechanics and local hidden variable based theories. The contradiction relies on non-maximally entangled position states of two particles.
@article{arxiv.quant-ph/0410160,
title = {Realisation of Hardy's Thought Experiment},
author = {William T. M. Irvine and Juan F. Hodelin and Christoph Simon and Dirk Bouwmeester},
journal= {arXiv preprint arXiv:quant-ph/0410160},
year = {2009}
}