High Energy Physics

In this talk I will discuss the universal properties of thermal transport in conformal field theories that are perturbed by a TTbar operator. TTbar-deformation is known to be an exactly solvable deformation in that the spectrum of the undeformed theory alone suffices to predict that of the deformed theory. Unique properties of TTbar deformation allow us to study the TTbar-deformed CFTs using two disparate methods: integrability and holography. I will apply these two approaches to study the non-equilibrium steady states and Drude weights, finding perfect agreement. I will also explain how the integrability-based approach yields the exact momentum diffusion constant, which, to our surprise, also happens to satisfy a universal formula. Finally I will briefly touch upon a curious connection between TTbar-deformed CFTs and an integrable cellular automaton model called the Rule 54 chain.

This talk will be split into two distinct halves: The first half will be based on the paper arxiv:2007.03662 and suggest that an interplay between microscopic and macroscopic physics can lead to an undulation on time scales not related to celestial dynamics. By searching for such undulations, the discovery potential of light DM search experiments can be enhanced.
The second half will look at some currently unpublished work into finding all the semi-simple subalgebras of u(48) which contain the SM. Such algebras (in a loose sense of the term) form GUTs and studying them has relevance to family unification, proton decay etc. Although there has been previous work into the classification of GUTs, we believe this is the first this broad question has been answered.

The Ryu Takayanagi formula identifies the area of  extremal surfaces in AdS with the entanglement entropy of the boundary CFT. However the bulk microstate interpretation of the extremal area remains mysterious. Progress along this direction requires understanding how to define entanglement entropy in the bulk closed string theory. As a toy model for AdS/CFT, we study the entanglement entropy of closed strings in the topological A model in the context of Gopakumar Vafa duality. We give a self consistent factorization of the closed string Hilbert space which leads to string edge modes transforming under a q-deformed surface symmetry group. Compatibility with this symmetry requires a q-deformed definition of entanglement entropy. Using the topological vertex formalism, we define the Hartle Hawking state for the resolved conifold and compute its q-deformed entropy directly from the closed string reduced density matrix.  We show that this is the same as the generalized entropy, defined by prescribing a contractible replica manifold for the closed string theory on the resolved conifold.  We then apply the Gopakumar Vafa duality to reproduce the closed string entropy from Chern Simons dual  using the un-deformed definition of entanglement entropy. Finally we relate non local aspects of our factorization map to analogous phenomenon recently found in JT gravity.

In recent years, there has been growing interest in cosmological first-order phase transitions in view of gravitational wave observations with space interferometers such as LISA. However, there is only limited understanding on the bubble dynamics and the gravitational wave signals arising from ultra-supercooled transitions (in which the released energy dominates the plasma energy, i.e., near-vacuum transitions), due to the highly relativistic nature of the transition.

In this talk, I introduce some approaches to understand the dynamics and the gravitational wave signals of ultra-supercooled first-order phase transitions:

(1) These transitions proceed with the propagation and collision of highly relativistic fluid profiles involving shock waves. I introduce an approach to construct an effective description of the propagation of such relativistic profiles (1905.00899).

(2) I present an approach to extend the existing model of gravitational wave production and calculate the gravitational wave signals analytically (1707.03111).

Dilaton-gravity models are integrable in two dimensions and admit a holographic description. In this talk, the holographic description of the Dilaton-gravity in flat spacetime is discussed. Using the gauge theory formulation of the model we obtain the boundary action which under certain boundary conditions is of the Warped-Schwarzian type. We calculate the 1-loop partition function of the model as the coadjoint orbit of the warped Virasoro group.

In the conventional weakly-interacting massive particle (WIMP) paradigm the late-time density of dark matter (DM) is set by the rate of two-body annihilations, but there has been considerable recent interest in exploring alternative DM scenarios where other interactions control the final abundance. I will show that by fully exploring the parameter space of a simple, weakly-coupled dark sector, we can find a rich set of novel pathways which lead to the observed relic density of DM. In particular, we can identify and characterize a general class of mechanisms in which the DM relic abundance is determined by processes controlling the thermal coupling of the DM and Standard Model (dubbed the KINetically DEcoupling Relic -- KINDER), generalizing previously-studied special cases of this behavior.

I will review the numerical approach to testing gauge/gravity duality using matrix models. This will lead to a summary of recent results from the BFSS, BMN and Berkooz-Douglas matrix models and a strong non-perturbative test of gauge/gravity duality.

One of the puzzles that the newly data-rich fields of cosmology and astrophysics are most advantaged to tackle is the nature of the dark sector.  In particular, a dark sector that thermalizes with the SM bath at some epoch has present-day observable properties that are directly tied to early-universe interactions. In this talk I survey some recent work on detecting different types of thermal dark particles by leveraging different cosmological and astrophysical datasets.  I discuss the utility of each of these different probes, the implication for particle theories, and prospects for the future. 

There is a deep relation between classical error-correcting codes, Euclidean lattices, and chiral 2d CFTs. We show this relation
extends to include quantum codes, Lorentzian lattices, and non-chiral CFTs. The relation to quantum codes provides a simple way to solve
modular bootstrap constraints and identify interesting examples of conformal theories. In particular we construct many examples of physically distinct isospectral theories, examples of "would-be" CFT partition function -- non-holomorphic functions satisfying all constraints of the modular bootstrap, yet not associated with any

known CFT, and find theory with the maximal spectral gap among all Narain CFTs with the central charge c=4. At the level of code theories the problem of finding maximal spectral gap reduces to the problem of finding optimal code, leading to "baby bootstrap" program. We also discuss averaging over the ensemble of all CFTs associated with quantum codes, and its possible holographic interpretation. The talk is based on arXiv:2009.01236 and arXiv:2009.01244.

I will study quantum error correcting codes that model aspects of the AdS/CFT correspondence. In an algebraic approach I will demonstrate the existence of a consistent assignment, to each boundary region, of conditional expectations that preserve the code subspace. This allows us to give simple derivations of well known results for these holographic code, and also to derive a few new results. 

I will also make a connection to the theory of QFT super-selection sectors.

Axion-like particles (ALPs) are one of the most attractive solutions to the dark matter issue. In this talk, I will discuss new ideas in the search for ALPs in astrophysical structures. In particular, I will focus on the emission associated with their decay into photons. The discussion will involve different ALP mass ranges and wavelength bands.