Gravity-related collapse of the wave function and spontaneous heating: revisiting the experimental bounds

TL;DR

This paper reevaluates experimental bounds on gravity-related wave function collapse models, especially the Di"osi-Penrose model, showing current heat leak measurements nearly exclude the model's parameter-free version.

Contribution

It analyzes new experimental constraints on the DP model from spontaneous heating, suggesting it is close to being ruled out by existing ultralow temperature heat leak data.

Findings

Parameter-free DP model nearly ruled out by heat leak measurements

Existing experiments already strongly constrain the model

Potential for conclusive exclusion with current technology

Abstract

The possibility that the collapse of the wave function in quantum mechanics is a real and ultimately connected to (classical) gravity has been debated for decades, with main contributions by Di\'osi and Penrose. In particular, Di\'osi proposed a noise-based dynamical reduction model, which captures the same orders of magnitude for the collapse time suggested by Penrose based on heuristic arguments. This is known in literature as the DP model (Di\'osi-Penrose). A peculiarity of the DP model is the prediction of spontaneous heating of matter, which can be tested without the need for massive quantum superpositions. Notably, a very similar effect is predicted by recent theoretical approaches to gravity as a classical-only information channel. Here, we reconsider the current constraints on the DP model from spontaneous heating, by analyzing experimental situations not properly considered before. We argue that the the parameter-free version of the DP model is close to be ruled out by standard heat leak measurements at ultralow temperature, with a conclusive exclusion likely within reach with existing technology. This result would strengthen a recent claim of exclusion inferred by spontaneous x-ray emission experiments, which relies on the somewhat stronger assumption that the DP noise field is white up to x-ray frequencies.