Scalable Generation of Massive Schr\"odinger Cat States via Quantum Tunneling

TL;DR

This paper demonstrates a scalable method to generate massive Schr"odinger cat states using ultracold atoms in optical lattices, enabling studies of quantum gravity and quantum superpositions at high masses.

Contribution

It introduces a novel approach to create and control high-mass spatial superpositions via quantum tunneling, surpassing previous mass limitations.

Findings

Observed coherent tunneling of bound atomic clusters with mass 608 amu.

Achieved full control of tunneling parameters to mitigate mass-related suppression.

Constructed an interferometer to certify entanglement and perform quantum-enhanced measurements.

Abstract

Massive objects in spatial superposition may provide insights into the interplay between quantum mechanics and gravity. Cold atomic interferometers offer a promising platform due to extended matter-wave coherence times and precise controllability. However, high-mass spatial superpositions beyond single atoms have yet to be generated in such setups. Here, we report the scalable realization of high-mass spatial entanglement via quantum tunneling of ultracold atoms in optical lattices. We observe coherent tunneling of bound clusters, forming a composite object with a mass of 608~amu. Full control of the model parameters allows us to mitigate the usual suppression of tunneling with increasing mass. Furthermore, we construct an interferometer to certify the entanglement and use spatially distributed Schr\"{o}dinger cat states to perform quantum-enhanced measurements. These results establish an approach to generating and detecting massive superposition states relevant to studies of quantum gravity.