LNS Special Seminars - 2018



4:00 p.m., Kolker Room, 26-414

First Results from the ABRACADABRA-10cm

Jonathan Oullet, MIT

The evidence for the existence of Dark Matter is well supported by many cosmological observations. Separately, long standing problems within the Standard Model point to new weakly interacting particles to help explain away unnatural fine-tunings. The axion was originally proposed to explain the Strong-CP problem, but was subsequently shown to be a strong candidate for explaining the Dark Matter abundance of the Universe. ABRACADABRA is a proposed experiment to search for ultralight axion Dark Matter, with a focus on the mass range 10-14 < ma < 10-6 eV. We search for these axions and other axion like particles (ALPs) through a modification to Maxwell's equations, which cause strong magnetic fields to source weak oscillating electrical currents parallel to the field. In this talk, I will describe the working principle behind the ABRACADABRA experiment and present the first results from a prototype experiment called ABRACADABRA-10 cm that we have built at MIT.


11:00 a.m., Kolker Room, 26-414

From nuts to soup: Recent advances in QCD in the Regge limit and the approach to thermalization in heavy-ion collisions

Raju Venugopalan, BNL

It was proposed about 25 years ago that the Regge limit of QCD could be described by a many-body classical effective field theory now known as the Color Glass Condensate (CGC). This conjecture was prompted by the phenomenon of gluon saturation, whereby many-body gluodynamics leads to the emergence of a semi-hard scale that screens color in the infrared. In the first part of this talk, we will review developments since in the CGC effective theory, and emphasize a paradigm shift in what constitutes fundamental degrees of freedom in the Regge limit. We shall also outline a color memory effect in the CGC which bears an exact analogy to the gravitational memory effect that could be discovered by LIGO in the near future. This correspondence in turn prompts one to speculate that asymptotic BMS-like symmetries analogous to those in gravity may also apply in QCD's Regge limit, leading to novel insight into how pions form "soft hair" on glue. In the second part of the talk, we discuss how the CGC provides an ab initio picture of thermalization and hydrodynamics in ultrarelativistic heavy-ion collisions. We focus on the discovery of a pre-thermal turbulent attractor, its topological properties, and a remarkable universality between this attractor and cold atomic gases prepared with the same boundary conditions.