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.

Title: probing beyond ETH at large c

Abstract: Eigenstate thermalization hypothesis (ETH) is a phenomena often observed in systems characterized by quantum chaos. In this talk, we study ETH in 2d CFTs with large central charges. In particular, we focus on observables consisting of bilocal "probe" operators $\mathcal{O}_L(x)\mathcal{O}_L(0)$. A sharp feature of ETH in this context is the so-called "forbidden" singularities, arising in the thermodynamic limit $c\to\infty$. We explore their resolutions by finite $c$ effects, and analyze the associated non-perturbative phenomena. We also discuss some interesting similarities between the related real-time dynamics and the spectral form factors in both the SYK model and BTZ black holes.

There exists a class of ultralight Dark Matter (DM) models which could form a Bose-Einstein condensate (BEC) in the early universe and behave as a single coherent wave instead of individual particles in galaxies. We show that a generic BEC DM halo intervening along the line of sight of a gravitational wave (GW) signal could induce an observable change in the speed of GW, with the effective refractive index depending only on the mass and self-interaction of the constituent DM particles and the GW frequency. Hence, we propose to use the deviation in the speed of GW as a new probe of the BEC DM parameter space. With a multi-messenger approach to GW astronomy and/or with extended sensitivity to lower GW frequencies, the entire BEC DM parameter space can be effectively probed by our new method in the near future.

We will discuss a simple model of low-energy baryon number violation in order to simultaneously explain the observed matter-antimatter asymmetry and dark matter relic density in the universe. The stability of dark matter is related to the stability of the proton. The model predicts a sizeable rate for the neutron-antineutron oscillation at low energy and a new type of monojet signal at the LHC. There exists an interesting complementarity between the observed baryon asymmetry, ratio of dark matter and baryon abundances, neutron-antineutron oscillation lifetime and the LHC monojet signal. 

Title: Baryogenesis, Dark Matter, Neutron-Antineutron Oscillation and Collider Signals

Abstract: We will discuss a simple model of low-energy baryon number violation in order to simultaneously explain the observed matter-antimatter asymmetry and dark matter relic density in the universe. The stability of dark matter is related to the stability of the proton. The model predicts a sizeable rate for the neutron-antineutron oscillation at low energy and a new type of monojet signal at the LHC. There exists an interesting complementarity between the observed baryon asymmetry, ratio of dark matter and baryon abundances, neutron-antineutron oscillation lifetime and the LHC monojet signal. 

Title: modular Hamiltonian for free theories 

Title : Rotating traversable wormholes

Abstract : An interaction that couples the two boundaries of  an eternal BTZ black hole produces a violation of the average null energy condition and makes the wormhole traversable. I will review this scenario and present work in progress where we consider a rotating black hole. We study the effect of rotation in the size of the wormhole and the amount of information transferred.