Search Talks

High temperatures are typically thought to increase disorder. Here we examine this idea in Quantum Field Theory in 2+1 dimensions. For this sake we explore a novel class of tractable models, consisting of nearly-mean-field scalars interacting with critical scalars. We identify UV-complete, local, unitary models in this class and show that symmetry breaking $\mathbb{Z}_2 \to \emptyset$ occurs at any temperature in some regions of the phase diagram. This phenomenon, previously observed in models with fractional dimensions, or in the strict planar limits, or with non-local interactions, is now exhibited in a local, unitary 2+1 dimensional model with a finite number of fields.

I describe a new solution to the Higgs hierarchy problem based on a dynamical vacuum selection mechanism in a landscape which scans the Higgs mass. The Higgs potential only admits a stable minimum when its mass is less than a critical value, cosmologically crunching away patches with a heavier Higgs. This critical value is set by the instability scale where the Higgs quartic turns negative. I consider the phenomenology of two explicit models that address the hierarchy problem in this context.

In this talk I will outline a fundamentally quantum description of bosonic dark matter from which the conventional classical-wave picture emerges when the mass is far below 10 eV. Exploiting fundamental results from quantum optics I will argue that the density matrix for dark matter is explicitly mixed. The formalism provides a continuous description of DM through the wave-particle transition, and using this I show how density fluctuations over various physical scales evolve between the two limits, with a unique behavior for DM emerging near the boundary of the wave and particle descriptions. If time permits, I will briefly describe how these effects would appear in axion haloscopes.