Abstract: Cosmological phase transitions that proceed via nucleation of bubbles are a well-motivated possibility both in minimal extensions of the Standard Model as well as in more general hidden sectors with their own dynamics. In this talk, I will discuss the dynamics of expanding vacuum bubbles in the presence of massive dark photons that gain mass across the interface — with a special focus on the … Read More
Abstract: Direct detection experiments looking for sub-GeV dark matter (DM) through nuclear recoils have already placed constraints down to DM masses ~ 100 MeV with energy thresholds of ~ 10 eV. Challenges in achieving sensitivity to lower DM masses include precisely calculating the DM scattering rates through multi-phonons, and understanding as well as mitigating backgrounds in low-threshold detectors. In this seminar, … Read More
“Due to the large scale separations involved, matching is an essential laborious step in the computations to compare high-energy new physics models with experimental data. Matchete is a Mathematica package that automates the one-loop matching from any generic ultraviolet (UV) model to a low-energy effective field theory (EFT) including, but not limited to, SMEFT. The program takes as input a … Read More
First order phase transitions can leave relic pockets of false vacua and their particles, that manifest as macroscopic Dark Matter. I present one predictive model: a gauge theory with a dark quark relic heavier than the confinement scale. During the first order phase transition to confinement, dark quarks remain in the false vacuum and get compressed, forming Fermi balls that … Read More
Abstract: “I will describe an attractive extension of the standard model based on quark-lepton unification. This theory is one of the few options to extend the SM gauge symmetry group via one step breaking, and given its economic matter content and its predictive capabilities, it is worth exploring. The advantages and appeal of this theory will be discussed, emphasizing on its … Read More
Abstract: The near equality of the dark matter and baryon energy densities is a remarkable coincidence, especially when one realizes that the baryon mass is exponentially sensitive to UV parameters in the form of dimensional transmutations. We explore a new dynamical mechanism, where in the presence of an arbitrary number density of baryons and dark matter, a scalar adjusts the … Read More
ABSTRACT: The phenomenon of cosmological gravitational particle production (CGPP) occurs during and after inflation as light fields “feel” the cosmological expansion and their mode functions evolve non-adiabatically. CGPP is a compelling and minimal explanation for the origin of dark matter, which might only interact gravitationally, as well as other cosmological relics. Various studies have explored CGPP for massive particles with spin … Read More
TITLE: Gravitational Portals and Particle Production during Reheating ABSTRACT: For many applications, reheating after inflation can be treated as a (nearly) instantaneous process. However, it is not, and the evolution of the inflaton condensate and the emerging radiation bath may play a role in particle production.The production of matter and radiation during reheating after inflation is considered with an emphasis … Read More
In this talk, I will present our recent proposal of searching for axion dark matter with an optomechanical cavity filled with a material such as superfluid helium. Axion absorption converts a pump laser photon to a photon plus a phonon. The axion absorption rate is enhanced by the high occupation number of coherent photons and phonons in the cavity, allowing … Read More
Abstract: The simplest single-field inflationmodels capture all the relevant contributions to the patterns in the CosmicMicrowave Background (CMB) observed today. A key assumption in these models isthat the quantum inflationary fluctuations that source such patterns aregenerated by a particular quantum state—the Bunch-Davies (BD) state. While thisis a well-motivated choice from a theoretical perspective, the question arisesof whether current data can … Read More