Improved bounds on collapse models from rotational noise of LISA Pathfinder

TL;DR

This paper uses LISA Pathfinder's rotational data to set tighter bounds on collapse models like CSL, highlighting the effectiveness of rotational measurements over translational ones for such constraints.

Contribution

It introduces a novel approach to constrain collapse models using rotational noise data from LISA Pathfinder, improving existing bounds and identifying conditions favoring rotational measurements.

Findings

Rotational data provides stronger constraints on CSL parameters.

Rotational measurements can outperform translational ones in testing collapse models.

New bounds surpass previous limits set by translational motion analysis.

Abstract

Spontaneous wavefunction collapse models offer a solution to the quantum measurement problem, by modifying the Schr\"odinger equation with nonlinear and stochastic terms. The Continuous Spontaneous Localisation (CSL) model is the most studied among these models, with phenomenological parameters that are constrained by experiments. Here, we exploit the recent analysis of LISA Pathfinder's angular motion data to derive a tighter constraint than previously achieved with translational motion. Moreover, we identify the general conditions for preferring rotational measurement over translational ones for constraining the CSL model.