2017/05/17 by Ralf Menzel, Menzel, Ralf, Axel Heuer +3 · 1 citation
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Spectroscopy and Quantum Chemical Studies #Quantum Mechanics and Applications
paper · pdf · doi:10.48550/arxiv.1705.06030
Using two crystals for spontaneous parametric down-conversion in a parallel\nsetup, we observe two-photon interference with high visibility. The high\nvisibility is consistent with complementarity and the absence of which-path\ninformation. The observations are explained as effects of entanglement or\nequivalently in terms of interfering probability amplitudes, and also by the\ncalculation of a second-order field correlation function in the Heisenberg\npicture. The latter approach brings out explicitly the role of the vacuum\nfields in the down-conversion at the crystals and in the photon coincidence\ncounting. For comparison we show that the Hong-Ou-Mandel dip can be explained\nby the same approach in which the role of the vacuum signal and idler fields,\nas opposed to entanglement involving vacuum states, is emphasized.\n