An atomically thin matter-wave beamsplitter

TL;DR

This paper demonstrates that atomically thin graphene and other nanomaterials can serve as effective, high-contrast matter-wave beamsplitters, preserving quantum coherence even at minimal thicknesses, thus advancing quantum interferometry with massive objects.

Contribution

It introduces ultra-thin nanomasks made from graphene and other materials as novel matter-wave beamsplitters that minimize dephasing effects in quantum interferometry.

Findings

Ultra-thin nanomasks enable high-contrast diffraction of massive molecules.

Quantum coherence persists with atomically thin gratings.

Transforming graphene nanoribbons into carbon nanoscrolls enhances grating performance.

Abstract

Matter-wave interferometry has become an essential tool in studies on the foundations of quantum physics and for precision measurements. Mechanical gratings have played an important role as coherent beamsplitters for atoms, molecules and clusters since the basic diffraction mechanism is the same for all particles. However, polarizable objects may experience van der Waals shifts when they pass the grating walls and the undesired dephasing may prevent interferometry with massive objects. Here we explore how to minimize this perturbation by reducing the thickness of the diffraction mask to its ultimate physical limit, i.e. the thickness of a single atom. We have fabricated diffraction masks in single-layer and bilayer graphene as well as in 1 nm thin carbonaceous biphenyl membrane. We identify conditions to transform an array of single layer graphene nanoribbons into a grating of carbon nanoscrolls. We show that all these ultra-thin nanomasks can be used for high-contrast quantum diffraction of massive molecules. They can be seen as a nanomechanical answer to the question debated by Bohr and Einstein whether a softly suspended double slit would destroy quantum interference. In agreement with Bohr's reasoning we show that quantum coherence prevails even in the limit of atomically thin gratings.