Abstract The Laser Interferometer Space Antenna (LISA) has two scientific objectives of
cosmological focus: to probe the expansion rate of the universe, and to understand …

It is commonly assumed that the energy density of the Universe was dominated by radiation
between reheating after inflation and the onset of matter domination 54,000 years later …

Pulsar timing arrays (PTAs) have reported evidence for a stochastic gravitational wave (GW)
background at nanohertz frequencies, possibly originating in the early Universe. We show …

We discuss the interpretation of the detected signal by pulsar timing array (PTA)
observations as a gravitational wave background of cosmological origin. We combine …

We analyze cosmic superstring models in light of NANOGrav 15-year pulsar timing data. A
good fit is found for a string tension G μ∼ 10-12–10-11 and a string intercommutation …

Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave
background (SGWB). However, the NANOGrav Collaboration has recently reported strong …

The North American Nanohertz Observatory for Gravitational Waves has recently reported
strong evidence for a stochastic common-spectrum process affecting the pulsar timing …

We outline the experimental concept and key scientific capabilities of AION (Atom
Interferometer Observatory and Network), a proposed experimental programme using cold …

In this work, we construct promising model-building routes towards SO (10) grand unified
theory inflation and examine their ability to explain the recent pulsar timing arrays (PTAs) …

Cosmic string networks offer one of the best prospects for detection of cosmological
gravitational waves (GWs). The combined incoherent GW emission of a large number of …