Design of high-efficiency UHV loading of nanodiamonds into a Paul trap: Towards Matter-Wave Interferometry with Massive Objects

TL;DR

This paper reviews and develops methods for efficiently loading nanodiamonds into a Paul trap under ultra-high vacuum conditions, aiming to enable matter-wave interferometry experiments with massive particles to test fundamental physics.

Contribution

It introduces a novel nanodiamond loading method for UHV conditions and discusses experimental techniques to improve loading efficiency for quantum gravity tests.

Findings

Successful loading and launching of nanodiamonds using piezoelectric and electrical methods

Design of a new nanodiamond loading technique for UHV environments

Enhanced loading efficiency for interferometric applications

Abstract

Quantum mechanics (QM) and General relativity (GR), also known as the theory of gravity, are the two pillars of modern physics. A matter-wave interferometer with a massive particle, can test numerous fundamental ideas, including the spatial superposition principle - a foundational concept in QM - in completely new regimes, as well as the interface between QM and GR, e.g., testing the quantization of gravity. Consequently, there exists an intensive effort to realize such an interferometer. While several paths are being pursued, we focus on utilizing nanodiamonds as our particle, and a spin embedded in the ND together with Stern-Gerlach forces, to achieve a closed loop in space-time. There is a growing community of groups pursuing this path [1]. We are posting this technical note (as part of a series of seven such notes), to highlight our plans and solutions concerning various challenges in this ambitious endeavor, hoping this will support this growing community. In this work, we review current methods for loading nanodiamonds into a Paul trap, and their capabilities and limitations regarding our application. We also present our experiments on loading and launching nanodiamonds using a vibrating piezoelectric element and by electrical forces. Finally, we present our design of a novel nanodiamond loading method for ultra-high-vacuum experiments. As the production of highly accurate, high-purity nanodiamonds with a single NV required for interferometric measurements is expected to be expensive, we put emphasis on achieving high loading efficiency, while loading the charged ND into a Paul trap in ultra-high vacuum.