Highlighted Paper!

28.03.2018

Our Publication on Gravitationally induced phase shift on a single photon was highlighted in New Journal of Physics.

Our Publication on Gravitationally induced phase shift on a single photon was highlighted in New Journal of Physics, Highlights of 2017.

 

The effect of the Earth's gravitational potential on a quantum wave function has only been observed for massive particles. In this paper we present a scheme to measure a gravitationally induced phase shift on a single photon traveling in a coherent superposition along different paths of an optical fiber interferometer. To create a measurable signal for the interaction between the static gravitational potential and the wave function of the photon, we propose a variant of a conventional Mach–Zehnder interferometer. We show that the predicted relative phase difference of 10−5 rad is measurable even in the presence of fiber noise, provided additional stabilization techniques are implemented for each arm of a large-scale fiber interferometer. Effects arising from the rotation of the Earth and the material properties of the fibers are analysed. We conclude that optical fiber interferometry is a feasible way to measure the gravitationally induced phase shift on a single-photon wave function, and thus provides a means to corroborate the equivalence of the energy of the photon and its effective gravitational mass.

 

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Schematic of a conventional Mach–Zehnder interferometer of area A = lh placed vertically inside Earth's gravitational field. A beam splitter (BS) transforms a single photon into a coherent superposition between the two possible arms. The wave function evolves along two different paths and arrives at the merging beam splitter at the same time but slightly shifted in phase due to the presence of a gravitational potential.