Breaking quantum linearity: constraints from human perception and cosmological implications

TL;DR

This paper investigates the possibility that quantum linearity breaks at certain scales, using human perception and cosmological data to set new bounds on collapse models, with implications for testability and cosmology.

Contribution

It provides a new lower bound on the collapse parameter from human visual analysis, significantly tightening previous constraints and linking collapse mechanisms to cosmological fields.

Findings

Lower bound on collapse parameter lambda is ~7 +/- 2 orders of magnitude stronger.

Collapse becomes effective in systems with ~10^4 - 10^5 nucleons.

Cosmological fields can potentially induce wave function collapse.

Abstract

Resolving the tension between quantum superpositions and the uniqueness of the classical world is a major open problem. One possibility, which is extensively explored both theoretically and experimentally, is that quantum linearity breaks above a given scale. Theoretically, this possibility is predicted by collapse models. They provide quantitative information on where violations of the superposition principle become manifest. Here we show that the lower bound on the collapse parameter lambda, coming from the analysis of the human visual process, is ~ 7 +/- 2 orders of magnitude stronger than the original bound, in agreement with more recent analysis. This implies that the collapse becomes effective with systems containing ~ 10^4 - 10^5 nucleons, and thus falls within the range of testability with present-day technology. We also compare the spectrum of the collapsing field with those of known cosmological fields, showing that a typical cosmological random field can yield an efficient wave function collapse.