Beyond quantum mechanics? Hunting the 'impossible' atoms (Pauli Exclusion Principle violation and spontaneous collapse of the wave function at test)

TL;DR

This paper investigates the foundations of quantum mechanics by testing potential violations of the Pauli Exclusion Principle and spontaneous wave function collapse, using experimental data from germanium X-ray spectra and the VIP experiment.

Contribution

It provides new experimental limits on collapse models and PEP violations, advancing the understanding of quantum foundations and measurement problem solutions.

Findings

Set an upper limit on the reduction rate parameter of collapse models.

Established a new limit on PEP violation probability for electrons.

Presented upgraded results of the VIP experiment searching for PEP violations.

Abstract

The development of mathematically complete and consistent models solving the so-called "measurement problem", strongly renewed the interest of the scientific community for the foundations of quantum mechanics, among these the Dynamical Reduction Models posses the unique characteristic to be experimentally testable. In the first part of the paper an upper limit on the reduction rate parameter of such models will be obtained, based on the analysis of the X-ray spectrum emitted by an isolated slab of germanium and measured by the IGEX experiment. The second part of the paper is devoted to present the results of the VIP (Violation of the Pauli exclusion principle) experiment and to describe its recent upgrade. The VIP experiment established a limit on the probability that the Pauli Exclusion Principle (PEP) is violated by electrons, using the very clean method of searching for PEP forbidden atomic transitions in copper.