# From the Bronshtein cube of limits to the degrees of freedom of relativistic quantum gravity

## TL;DR

This paper proposes that the quadruple gravitational constant and maximum force define fundamental limits shaping all physical theories, leading to a minimum length scale that informs the structure of space and particles in relativistic quantum gravity.

## Contribution

It extends the Bronshtein cube of theories to a cube of limits, establishing the minimum length as a key principle in relativistic quantum gravity.

## Key findings

- The quadruple gravitational constant 4G is a fundamental limit.
- The maximum force c^4/4G extends the theory limits.
- The minimum length deduces the structure of space and particles.

## Abstract

It is argued that the quadruple gravitational constant 4G can be seen as a fundamental limit of nature. The limit holds across all gravitational systems and distinguishes bound from unbound systems. Including the maximum force c^4/4G allows extending the Bronshtein cube of physical theories to a cube of limits. Every theory of physics refining Galilean physics - universal gravitation, special relativity, general relativity, quantum theory and quantum field theory - is defined by one fundamental limit. As a result, also relativistic quantum gravity is defined by a limit: the minimum length in nature. The minimum length is used to deduce the Planck-scale structure of space. Numerous options are eliminated. Then, the minimum length is used to deduce the main properties of the common constituents that make up space and particles.