Multi-Messenger Time Delays from Lensed Gravitational Waves

TL;DR

This paper explores how gravitational lensing-induced time delays between different types of astrophysical signals, such as gravitational waves and neutrinos, can be used to probe fundamental physics and cosmological parameters.

Contribution

It introduces the concept of 'massive time delay' as a novel way to test fundamental physics using multi-messenger signals affected by gravitational lensing.

Findings

Proposes using time delays between massless and massive particles to constrain neutrino mass.

Highlights the potential of gravitational lensing to probe cosmological parameters.

Identifies experimental challenges in measuring these time delays.

Abstract

We investigate the potential of high-energy astrophysical events, from which both massless and massive signals are detected, to probe fundamental physics. In particular, we consider how strong gravitational lensing can induce time delays in multi-messenger signals originating from the same source. Obvious messenger examples are massless photons and gravitational waves, and massive neutrinos, although more exotic applications can also be imagined, such as to massive gravitons or axions. The different propagation times of the massive and massless particles can, in principle, place bounds on the total neutrino mass and probe cosmological parameters. Whilst measuring such an effect may pose a significant experimental challenge, we believe that the `massive time delay' represents an unexplored fundamental physics phenomenon.