Coherence in the presence of absorption and heating in a molecule interferometer

• Published in: Nature communications Vol. 6; no. 1; p. 7336
• Main Authors: Cotter, J. P., Eibenberger, S., Mairhofer, L., Cheng, X., Asenbaum, P., Arndt, M., Walter, K., Nimmrichter, S., Hornberger, K.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-06-2015; Nature Publishing Group; Nature Pub. Group
• Subjects: 639/766/1130; 639/766/36/1121; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms8336

Matter-wave interferometry can be used to probe the foundations of physics and to enable precise measurements of particle properties and fundamental constants. It relies on beam splitters that coherently divide the wave function. In atom interferometers, such elements are often realised using lasers by exploiting the dipole interaction or through photon absorption. It is intriguing to extend these ideas to complex molecules where the energy of an absorbed photon can rapidly be redistributed across many internal degrees of freedom. Here, we provide evidence that center-of-mass coherence can be maintained even when the internal energy and entropy of the interfering particle are substantially increased by absorption of photons from a standing light wave. Each photon correlates the molecular center-of-mass wave function with its internal temperature and splits it into a superposition with opposite momenta in addition to the beam-splitting action of the optical dipole potential.
Extending matter-wave interferometry to nanoscale objects requires beam splitters that can cope with their internal complexity. Here, the authors demonstrate that the absorption of individual photons allows the center-of-mass coherence of large molecules to be maintained.