Abstract The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders
about the fundamental theory of nature at play in the extreme gravity regime, where the …

Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark
discovery, potentially providing a significant clue to some of our most basic, big-picture …

We present a set of tools to assess the capabilities of LISA to detect and reconstruct the
spectral shape and amplitude of a stochastic gravitational wave background (SGWB). We …

A bstract We explore whether the axion which solves the strong CP problem can naturally be
much lighter than the canonical QCD axion. The\({Z} _ {\mathcal {N}}\) symmetry proposed …

We show that dark matter can be accounted for by an axion that solves the strong CP
problem, but is much lighter than usual due to a Z Script N symmetry. The whole mass range …

Scalar boson stars have attracted attention as simple models for exploring the nonlinear
dynamics of a large class of ultracompact and black hole mimicking objects. Here, we study …

These TASI lectures where given in 2018 and provide an introduction to the Strong CP
problem and the axion. I start by introducing the Strong CP problem from both a classical …

The metastable hypermassive neutron star produced in the coalescence of two neutron stars
can copiously produce axions that radiatively decay into O (100) MeV photons. These …

Exploring dark matter via observations of extreme astrophysical environments--defined here
as heavy compact objects such as white dwarfs, neutron stars, and black holes, as well as …

In this white paper, we discuss the prospects for characterizing and identifying dark matter
using gravitational waves, covering a wide range of dark matter candidate types and signals …