The last few years have seen an explosion in our understanding of dualities in 2+1 dimensional quantum field theories. More and more examples are being uncovered, but a systematic understanding of the patterns is still missing. In this talk I will discuss how to use holography to generate large new classes of purely field theoretic dualities including generalizations of the well-studied particle/vortex duality.

Host: Pranjal Nayak

The SYK model provides an uncommon example of a theory where Eigenstate Thermalization Hypothesis (ETH) can be verified in analytically. In this talk I will discuss this model in the deep infrared limit where the theory has an emergent conformal (reparametrization) symmetry that is broken both spontaneously and explicitly. To study the validity of ETH, we compute the heavy- light correlation functions of operators in the conformal spectrum of the theory. We compute these correlation functions with and without the contribution of the low energy (Schwarzian) modes, which are known to be the origin of the chaotic behaviour in this theory. In considering the contributions of the Schwarzian modes we find a weaker form of ETH: while the heavy operator insertions increase the effective temperature perceived by the light insertions, this effective temperature is proportional to the background temperature and goes to zero with the background temperature. In the case where Schwarzian modes aren’t considered, we find ETH in limit in which the weight of the heavy operators approach infinity. I will also discuss implications of these results for the states in AdS2 gravity dual.

Description: The axion is a proposed particle whose existence might account for much of the dark matter of the universe. This same particle also arises as the solution to the strong-CP problem of particle physics. There have been several decades of experiments that have attempted to detect new particles with many of the properties of the axion - but without being sensitive to the preferred region of parameter space. I will report on the Axion Dark Matter Experiment, ADMX, which is currently running and is achieving the required sensitivity towards potential discovery. There are also new ideas in case nature has a related but different elusive solution to the dark matter problem - these will also be described with a focus on having discovery potential.

Host: Susan Gardner

I will discuss the definition and use of gravitational Wilson lines as a means of understanding the AdS/CFT dictionary. Applications will include the gravitational self-energy of point particles, and the late time behavior of Lorentzian correlators.

Host: Pranjal Nayak

Title: The Schwarzian and black hole physics

Abstract: In this talk, I will discuss the Schwarzian theory (relevant for low-energy SYK physics and Jackiw-Teitelboim gravity) from a 2d perspective. I will demonstrate how Schwarzian quantum mechanics is naturally embedded in 2d Liouville CFT. This perspective allows a direct computation of Schwarzian two- and four-point functions. Out-of-time ordered (OTO) four-point functions are also determined using the 2d R-matrix. The semi-classical limit of these expressions demonstrate various aspects of black holes, such as quasi-normal modes and eikonal shockwave expressions in the holographic bulk. In the end, I briefly discuss some generalizations to other theories. Mostly based on arXiv:1705.08408.

Path-Integral Complexity for Perturbed CFTs

Unitarity, causality and ghostbusting in non-equilibrium effective field theory

Abstract:

In this talk, I will discuss the dynamics of near-extremal Reissner-Nordstrom black holes in asymptotically four-dimensional Anti-de Sitter space (AdS4). In the spherically symmetric approximation and at low energies, the behaviour of the system in response to a probe scalar is well described by the Jackiw-Teitelboim (JT) model of gravity. In fact, this behaviour can be understood from symmetry considerations and arises due to the breaking of time reparametrisation invariance. The JT model has been analysed in considerable detail recently and related to the behaviour of the SYK model. The results that I will present indicate that features in these models which arise from symmetry considerations alone are more general and present quite universally in near-extremal black holes. 

Dark Matter (DM) provides strong evidence for physics beyond the Standard Model (SM). Arguably, rather than suggesting a specific mass scale for New Physics, it may point to a dark sector, weakly-coupled to the SM, as hinted at by the comparable abundances of dark matter and visible baryons. In the past few years, a program of new experiments has expanded DM searches far beyond the WIMP paradigm to include new hidden forces and matter. While this program has made impressive progress, there are considerable challenges that must be overcome to fully explore the viable dark sector scenarios over a wide range of mass scales. In this seminar, I will discuss new search strategies to test dark sectors at low-energy high-intensity experiments, with a special emphasis on existing and planned experiments at Fermilab. I will highlight the complementarity of these experiments with LHC searches and with DM direct and indirect detection experiments in probing the parameter space of well motivated models as, for example, models of Strongly Interacting Dark Matter or Inelastic Dark Matter.