Complementarity in variable strength quantum non-demolition measurements

Marco Barbieri (1, 2) , M.E. Goggin (2, 3) , M.P. Almeida (2) , B.P. Lanyon (2) , A.G. White (2)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Optique quantique
2 Department of Physics and Centre for Quantum Computer Technology
3 Physics Department

Using a linear optic quantum gate we perform a variable strength quantum non-demolition measurement, to elucidate the role of which-path knowledge in a complementarity experiment. Specifically, we demonstrate that the entanglement created by the measurement interaction prevents an exhaustive description in terms of complementary wave-like and particle-like behaviour of a single photon in an interferometer.

Domains: Quantum Physics [quant-ph]

Marco Barbieri, M.E. Goggin, M.P. Almeida, B.P. Lanyon, A.G. White. Complementarity in variable strength quantum non-demolition measurements. New Journal of Physics, 2009, 11, pp.093012. ⟨10.1088/1367-2630/11/9/093012⟩. ⟨hal-00569531⟩