Matthew Lewandowski

Anomalous dimensions and non-gaussianity

A bstractWe analyze the signatures of inflationary models that are coupled to interacting field theories, a basic class of multifield models also motivated by their role in providing dynamically small scales. Near the squeezed limit of the bispectrum, we find a simple scaling behavior determined by operator dimensions, which are constrained by the appropriate unitarity bounds. Specifically, we analyze two simple and calculable classes of examples: conformal field theories (CFTs), and large-N CFTs deformed by relevant time-dependent double-trace operators. Together these two classes of examples exhibit a wide range of scalings and shapes of the bispectrum, including nearly equilateral, orthogonal and local non-Gaussianity in different regimes. Along the way, we compare and contrast the shape and amplitude with previous results on weakly coupled fields coupled to inflation. This signature provides a precision test for strongly coupled sectors coupled to inflation via irrelevant operators suppressed by a high mass scale up to ~ 103 times the inflationary Hubble scale.

Analytic Prediction of Baryonic Effects from the EFT of Large Scale Structures

The large scale structures of the universe will likely be the next leading source of cosmological information. It is therefore crucial to understand their behavior. The Effective Field Theory of Large Scale Structures provides a consistent way to perturbatively predict the clustering of dark matter at large distances. The fact that baryons move distances comparable to dark matter allows us to infer that baryons at large distances can be described in a similar formalism: the backreaction of short-distance non-linearities and of star-formation physics at long distances can be encapsulated in an effective stress tensor, characterized by a few parameters. The functional form of baryonic effects can therefore be predicted. In the power spectrum the leading contribution goes as

EFT of large scale structures in redshift space

\propto k^2 P(k)

IR-safe and UV-safe integrands in the EFTofLSS with exact time dependence

, with

Nonlinear effective theory of dark energy

P(k)

An effective description of dark matter and dark energy in the mildly non-linear regime

being the linear power spectrum and with the numerical prefactor depending on the details of the star-formation physics. We also perform the resummation of the contribution of the long-wavelength displacements, allowing us to consistently predict the effect of the relative motion of baryons and dark matter. We compare our predictions with simulations that contain several implementations of baryonic physics, finding percent agreement up to relatively high wavenumbers such as

Leading slow roll corrections to the volume of the universe and the entropy bound

k\simeq 0.3\,h\, Mpc^{-1}

Towards Precision Constraints on Gravity with the Effective Field Theory of Large-Scale Structure

or

On the EFTofLSS in Redshift-Space

k\simeq 0.6\, h\, Mpc^{-1}

Gravitational Wave Decay into Dark Energy

, depending on the order of the calculation. Our results open a novel way to understand baryonic effects analytically, as well as to interface with simulations.