Gyroscopic stability for nanoparticles in Stern-Gerlach Interferometry and spin contrast

TL;DR

This paper explores how imparting angular momentum to nanoparticles in Stern-Gerlach interferometry can enhance spin contrast and spatial superposition, aiding quantum tests and sensing applications.

Contribution

It demonstrates that rotational angular momentum can significantly improve spin contrast and superposition size in nanoparticle interferometry.

Findings

Angular momentum enhances spin contrast over a wide range.

Rotation can nearly double the spatial superposition.

Imparted angular momentum may reduce effects of permanent dipoles.

Abstract

Creating macroscopic spatial quantum superposition with a nanoparticle has a multitude of applications, ranging from testing the foundations of quantum mechanics, matter-wave interferometer for detecting gravitational waves and probing the electromagnetic vacuum, dark matter detection and quantum sensors to testing the quantum nature of gravity in a lab. In this paper, we investigate the role of rotation in a matter-wave interferometer, where we show that imparting angular momentum along the direction of a defect, such as one present in the nitrogen-vacancy centre of a nanodiamond can cause an enhancement in spin contrast for a wide-ranging value of the angular momentum, e.g. $10^{3}-10^{6}$~Hz for a mass of order $10^{-14}-10^{-17}$ Kg nanodiamond. Furthermore, the imparted angular momentum can enhance the spatial superposition by almost a factor of two and possibly average out any potential permanent dipoles in the nanodiamond.