Scientific Program

We propose a novel analytic approach to the study of multi-component F-L-R-W cosmologies, including inflation, and their perturbations. For a large class of integrable models, governed by a fake super-potential, we show that the linearized equations coincide with quantum S-W curves for N=2 SYM theories and can be solved via semi-analytic techniques.

We propose that any compact d-manifold with elliptic data, J, prepares a quantum state |J⟩ on its (d − 1)-boundary σ. Elliptic data consists of metric and field values, or their conjugates, but not both. No asymptotic structure is required. Inner products and traces are evaluated by the gravitational path integral with closed boundary conditions obtained by gluing elliptic data manifolds. In particular, we give a prescription for the Rényi entropies Sₙ of a subregion of σ. In a class of examples, we find that Sₙ is nonnegative and nonincreasing with n, as required for consistency. We obtain the von Neumann entropy by analytic continuation and find agreement with the minimal surface prescription of Bousso and Penington.

Dualities are best understood in supersymmetric string compactifications, where classical geometry and topology remain powerful tools even at strong coupling. A remarkable recent proposal broadens the notion of compactification to include singular “quantum” spaces, such as two circles joined at a point to form a figure-eight. In this talk, I will use this idea to extend Hull’s classic construction of massive type IIA and propose an M-theory origin for the two massive deformations of non-supersymmetric type 0A string theory. The resulting "quantum fibration" geometrizes both Romans mass parameters. A key ingredient is a description of the type 0B duality group in terms of a marked elliptic curve.

We propose a symplectic structure for the phase space of a generic Lagrangian field theory formulated in terms of L∞ algebras. This structure does not require explicit knowledge of the derivative content of the Lagrangian, hence it is applicable to nonlocal theories—to string theory in particular. The proposal is tested in a number of examples and the elements of the resulting canonical formalism, such as conserved charges and the Poisson bracket, are described. Based on 2506.20706.

Towers of states and infinite distance limits in field space are known to play a crucial role in the breaking of gravitational EFTs. In this talk, I will focus on recent developments related to codimension-2 and codimension-1 solutions that dynamically explore such infinite distance limits: EFT strings and dynamical cobordisms. First, I will present an attempt to prove the Integral Scaling Conjecture, which relates the tension of EFT strings to the mass scale of the towers that become light along the flow, using the Emergent String Conjecture and related taxonomy rules. Then, I will motivate and present a necessary condition for the UV viability of dynamical cobordism solutions by combining swampland insights (including EFT strings themselves) with the well-known Gubser and Maldacena-Nuñez criteria.

Charged black holes can, in general, explore regions of moduli space far from their asymptotic values, where a perturbative description is no longer valid. This could pose a problem for arguments used to prove the weak gravity conjecture, as this requires control of the black hole solutions throughout moduli space.

In the talk I will present sharp bounds on the moduli space excursion that black hole solutions satisfy when the charge function satisfies certain conditions. In particular, these apply to electrically charged NSNS black holes, thus closing a potential loophole in the derivation of the weak gravity conjecture in perturbative string theory.

The Black Hole-String Correspondence identifies the microstates of a minimal black hole with those of a highly excited string. In decompactification limits, where the light states are Kaluza-Klein modes, its proposed counterpart is the Black Hole-Tower Correspondence at the species scale. We study this correspondence for towers with string oscillators and Kaluza-Klein modes. We find that the thermodynamic matching survives the inclusion of gravitational backreaction, and ask whether the two sides can be continuously connected. While such an interpolation exists in the heterotic string, in type II it is perturbatively obstructed by a mismatch in the brane-charge lattices. We argue, motivated by the cobordism conjecture, that the transition must then occur through a non-perturbative process.

We present a modern interpretation of the problem of radiative corrections to vacuum energy from the point of view of (-1)-form global symmetries associated with continuous couplings. It is generally argued that quantum gravity does not admit any global symmetries. We point out that, in fact, general relativity with a cosmological constant term posesses two (-1)-form global symmetries: flat gauging one yields Henneaux-Teitelboim unimodular gravity; gauging both leads to local vacuum-energy sequester. While the latter is known to solve the problem of radiative corrections to vacuum energy, we propose a general diagnostic for determining whether a gravitational theory admits a cosmological constant problem. We also discuss parallels with the strong CP problem where topological susceptibility diagnoses the problem.

I will present an explicit non-susy string theory construction in which the particle physics contributions to the one-loop vacuum energy exactly cancel, whilst the gravitational contributions are suppressed in the size of one or two large extra dimensions, a.k.a "dark dimensions".  A moduli stabilisation scenario in which the final one-loop vacuum energy matches the observed Dark Energy scale, is also proposed.  I'll comment on higher loops.  Based on 2512.20570 in collaboration with Emilian Dudas and Marco Serra.

Different approaches to quantum gravity may admit very different microscopic descriptions, yet at sufficiently low energies they must all confront the same effective-field-theory questions.

In this talk, I will use EFT as a common language to explore the interplay between asymptotically safe quantum gravity and swampland ideas. After briefly reviewing the asymptotic safety program, I will explain how its underlying UV completion—an interacting fixed point of the gravitational RG flow—selects a restricted landscape of infrared theories and imposes correlations among their Wilson coefficients. I will discuss how this landscape can be computed from renormalization-group flows and confronted with independent consistency criteria, including positivity bounds and some swampland conjectures. Finally, I will comment on the broader question of whether a fundamental field-theoretic description of gravity can be compatible with the principles underlying the swampland program and whether, alternatively, asymptotic safety could emerge as an effective description bridging EFT and a more fundamental theory.

I will discuss a new consistency condition for the compatibility of a gravitational effective field theory in AdS with a dual holographic description in terms of a family of large-N CFTs. Using large-N factorisation of correlation functions combined with a properly defined notion of single- and multi-particle operators, I will argue that the cubic scalar bulk couplings for fields dual to operators with extremal arrangements of the conformal dimensions, i.e. Δi=Δj+Δk, should vanish. Finally, I will apply this criterion to the 4d  effective supergravity theory describing the DGKT AdS4 vacua in type IIA string theory, and show that the constraint is satisfied if and only if the compactification manifold is rigid.

Supersymmetry and extra dimensions play central roles in several proposals that extend beyond the Standard Model and General Relativity. Yet, there is still no experimental evidence for either. Is this merely a coincidence, or could it reflect fundamental properties of quantum gravity? In this talk, I will discuss how insights from the Swampland program can shed light on the interplay between supersymmetry breaking and extra dimensions, and on possible links between their characteristic scales and observable physics.

An expanding bubble in AdS₅ has a dS₄ geometry; the dark bubble scenario explores whether this can be our Universe. I will describe new realizations of this idea in M-theory. The most interesting one has a flag manifold as internal space. The effective cosmological constant can be tuned to small values. As one does so, the extra dimensions grow, but slowly: R ∼ Λ₄^(−1/4), getting intriguingly close to current data for extra dimensions.

Flux compactifications across all five ten-dimensional superstring theories seem to give rise to AdS vacua in d = 2, 3, 4 dimensions, for which the AdS length scale can be parametrically larger than the KK length scale of the internal space. In this parametric limit string-loop and higher-order α′ corrections are parametrically suppressed, so that a supergravity analysis should be applicable, at least away from the localized sources that in many constructions are treated in the smeared approximation. However, for none of these vacua do we understand the putative dual CFT. In this talk I will discuss the latest constructions of scale-separated AdS vacua for d = 2, 3, as well as the current status of trying to understand their dual CFTs in d − 1 dimensions.