  Over the past few decades, astronomical and cosmological data sets firmly
established the existence of physics beyond the Standard Model of particle
physics by providing strong evidence for the existence of dark matter, dark
energy, and non-zero neutrino mass. In addition, the generation of primordial
perturbations most likely also relies on physics beyond the Standard Model of
particle physics. Theory work, ranging from models of the early universe in
string theory that that led to novel phenomenological predictions to the
development of effective field theories to large-scale cosmological simulations
that include the physics of galaxy evolution, has played a key role in
analyzing and interpreting these data sets and in suggesting novel paths
forward to isolate the origins of this new physics. Over the next decade, even
more sensitive surveys are beginning to take data and are being planned. In
this white paper, we describe key areas of the theory program that will be
needed to optimize the physics return on investment from these new
observational opportunities.
