Can the Copernican principle be tested by cosmic neutrino background?

TL;DR

This paper proposes using the cosmic neutrino background as a novel observational test to verify the validity of the Copernican principle in cosmology, considering neutrinos' unique propagation properties.

Contribution

It introduces a new method to test the Copernican principle using cosmic neutrino background, highlighting the potential of neutrino observations to challenge or confirm cosmological assumptions.

Findings

Cosmic neutrino background can theoretically test the Copernican principle.

Larger neutrino detectors are needed for practical implementation.

Neutrino energy-dependent observations can reveal universe's large-scale structure.

Abstract

The Copernican principle, stating that we do not occupy any special place in our universe, is usually taken for granted in modern cosmology. However recent observational data of supernova indicate that we may live in the under-dense center of our universe, which makes the Copernican principle challenged. It thus becomes urgent and important to test the Copernican principle via cosmological observations. Taking into account that unlike the cosmic photons, the cosmic neutrinos of different energies come from the different places to us along the different worldlines, we here propose cosmic neutrino background as a test of the Copernican principle. It is shown that from the theoretical perspective cosmic neutrino background can allow one to determine whether the Copernican principle is valid or not, but to implement such an observation the larger neutrino detectors are called for.