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

J P Cotter,S Eibenberger,L Mairhofer,P Asenbaum,S Nimmrichter,M Arndt,K Walter,X Cheng,K Hornberger

doi:10.1038/ncomms8336

Abstract

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.

Highlights

Matter-wave interferometry can be used to probe the foundations of physics and to enable precise measurements of particle properties and fundamental constants
The absorption of a photon can be followed by spontaneous emission into free space which can result in decoherence[19,20,21,22]
We demonstrate KDTL interferometry in a regime where a three-component beam-splitting mechanism occurs in a standing light wave

Summary

Introduction

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. Coherent beam splitters have been realised with material nanomasks[6,7] as well as using standing light waves as phase[8,9,10,11] or amplitude gratings[12,13]. They have been implemented using resonant laser light to drive coherent transitions between vibrational[14], electronic[15] or hyperfine[16] states as well as off-resonant light in Bragg diffraction[17] and Bloch oscillations[18]. Because a molecule can only interfere with itself as long as all internal states are identical, only wave components of the same temperature class will interfere with each other

Methods

Results

Conclusion