Relative locality: A deepening of the relativity principle

TL;DR

This paper introduces the principle of relative locality, suggesting that at quantum gravitational scales, the geometry of momentum space influences locality and can be experimentally probed through astrophysical observations.

Contribution

It proposes that the Planck mass governs the curvature of momentum space, affecting the concept of locality in quantum gravity regimes.

Findings

Momentum space may have a curved geometry at Planck scale.

Locality depends on the energy used to probe spacetime.

Potential for experimental measurement via astrophysical data.

Abstract

We describe a recently introduced principle of relative locality which we propose governs a regime of quantum gravitational phenomena accessible to experimental investigation. This regime comprises phenomena in which $\hbar$ and $G_N$ may be neglected, while their ratio, the Planck mass $M_p =\sqrt{\hbar / G_N}$, is important. We propose that $M_p$ governs the scale at which momentum space may have a curved geometry. We find that there are striking consequences for the concept of locality. The description of events in spacetime now depends on the energy used to probe it. But there remains an invariant description of physics in phase space. There is furthermore a reasonable expectation that the geometry of momentum space can be measured experimentally using astrophysical observations.