SciPost logo

Why space could be quantised on a different scale to matter

Matthew J. Lake

SciPost Phys. Proc. 4, 014 (2021) · published 13 August 2021

Proceedings event

4th International Conference on Holography, String Theory and Discrete Approach in Hanoi


The scale of quantum mechanical effects in matter is set by Planck's constant, $\hbar$. This represents the quantisation scale for material objects. In this article, we present a simple argument why the quantisation scale for space, and hence for gravity, may not be equal to $\hbar$. Indeed, assuming a single quantisation scale for both matter and geometry leads to the `worst prediction in physics', namely, the huge difference between the observed and predicted vacuum energies. Conversely, assuming a different quantum of action for geometry, $\beta \ll \hbar$, allows us to recover the observed density of the Universe. Thus, by measuring its present-day expansion, we may in principle determine, empirically, the scale at which the geometric degrees of freedom should be quantised.

Author / Affiliations: mappings to Contributors and Organizations

See all Organizations.
Funder for the research work leading to this publication