I explore decoupling limits that lead to matrix theories on D-branes, focusing on their BPS nature and the emergence of non-Lorentzian target space geometries. In these limits, D-branes experience instantaneous gravitational forces, and when applied to curved geometries, it is shown that a single decoupling limit leads to the AdS/CFT correspondence. By applying two such limits, we generate new...
In recent years there has been a growing interest in various non-Lorentzian limits of String and M-theory. In this talk I will outline my work with Joe Smith on novel non-Lorentzian field theories obtained from limits of branes. The dynamics of these theories typically reduce to motion on a moduli space. We also discuss the limits of their associated gravitational solutions which lead to new...
Integrability and holography have played a huge role in understanding string theory in AdS$_5 \times$S$^5$, so it is worth studying if they survive in the non-relativistic string theory. In this talk, I will show that the Maldacena's construction of the AdS$_5$/CFT$_4$ correspondence survives the limit process, giving us a duality between NR string theory in SNC AdS$_5 \times$S$^5$ and...
I will talk about two classes of nonrelativistic sigma models and their roles in M-theory and matrix theory. I will start with the quantum critical supermembrane and its quantization, which is described by a renormalizable three-dimensional sigma model at a z=2 Lifshitz point. This model provides a natural candidate high-energy completion of the supermembrane in M-theory, where the latter is...
I will discuss the surprising structure of non-relativistic 11-dimensional supergravity, and some of its supersymmetric solutions, based on https://arxiv.org/abs/2407.21648 and https://arxiv.org/abs/2503.21577
In this talk, I will show how we used the covariant $1/c$-expansion to construct a framework for post-Newtonian gravity that is valid in any gauge with a Newtonian regime. This is not true for every gauge as Newtonian gravity itself is a gauge fixed version of Newton-Cartan gravity. Thus, we fix the leading order gauge choice but keep full gauge freedom at all subleading orders in this...
We review the study of Carroll limits on partition functions of relativistic conformal theories and their thermodynamics. We focus on 2d holographic CFTs and revisit the connection between the Carroll limit and the flat space limit of BTZ black holes. The general picture, valid in any dimension, is that, starting from AdS/CFT, the boundary Carrollian field theory lives on the horizon of a...
Galilean and Carrollian algebras are dual contractions of the Poincaré algebra. They act on two-dimensional Newton-Cartan and Carroll manifolds and are isomorphic. A consequence of this property is a duality correspondence between one-dimensional Galilean and Carrollian fluids. I will describe the dynamics of these systems as they emerge from the relevant limits of Lorentzian hydrodynamics,...
Carrollian holography proposes that gravity in four-dimensional (4d) asymptotically flat spacetime is dual to a 3d Carrollian CFT living at null infinity. In this talk, I will review this framework and explain how massless amplitudes in flat space can be re-expressed as Carrollian CFT correlators at the boundary, referred to as Carrollian amplitudes. I will show that these correlators...
We study null open strings and establish, for the first time, that the worldsheet residual gauge symmetry algebra is the Boundary Carrollian Conformal Algebra (BCCA). We present the construction of open null strings and demonstrate that, under Dirichlet boundary conditions, Boundary Carrollian Conformal Algebra emerges as the algebra of constraints. Additionally, we show that the BCCA can be...
In this talk, I will outline how to take the first step in the conformal program for constructing general matter couplings to Carroll gravity. In particular, I will show how a (non-conformal version of) electric/magnetic Carroll gravity arises from gauge-fixing a theory of a single massless electric/magnetic scalar coupled to conformal Carroll gravity with isotropic dilatations. Special...
The concept of fracton quasiparticle has recently emerged in many areas of physics, from mathematical physics to condensed matter and quantum information, unified by the general feature of restricted mobility.
In this talk I will show that the fracton phenomenology of Pretko's original papers [1604.05329,1606.08857] can be reproduced from first principles of QFT through a symmetry-based...
I discuss the impact of the positive cosmological constant on the interplay between the equivalence principle in general relativity, and the rules of quantum mechanics. There is an ambiguity in the definition of a phase of a wave function measured by inertial and accelerating observers which is a non-relativistic analogue of the Unruh effect. This will be put in the framework of a...
I will report on joint work with Girish Vishwa about a construction of nonrelativistic quantum strings from gauged WZW models. This is inspired on the characterisation of Lie groups admitting a bi-invariant galilean structure as quotients of generalised Nappi-Witten groups.
