A single network of cracks in the fabric of space explains both the speed of the universe and the mysterious humming of gravitational waves.
Astronomers are currently stumped by why the universe seems to expand at two different speeds. They are also trying to find the source of the low-frequency gravitational waves that seem to fill the sky. This model uses transient domain walls, essentially boundaries in spacetime, to explain both mysteries at once. These networks would have provided the extra energy needed to speed up expansion while creating the gravitational hum as they decayed. It provides a unified answer to two of the biggest questions in modern cosmology using one simple mechanism.
Transient Domain-Wall Networks from Spontaneous Symmetry Breaking: A Unified Solution to the Hubble Tension and Nanohertz Gravitational Waves
SSRN · 6642583
We present a cosmological model where an initially symmetric two-field scalar sector undergoes spontaneous symmetry breaking, leading to the formation of a transient domain-wall network. Starting from a fundamental action, we derive the full background dynamics and show that the coarse-grained energy density of the network scales as ρDW ∝ H during a metastable scaling regime. This introduces a linear correction term in the Friedmann equation, generating a late-time enhancement of the expansion r