Schedule

Per Sundell (UNAP)

Title: "Unfolding 4d QFT"

Abstract: We advertise the construction of second-quantised fields as operators in sigma models of AKSZ type with sources and targets unified in first-quantised noncommutative geometries naturally yielding 6d chiral, conformal bosons and 4d higher-spin gravities.

Ki-Seok Kim (POSTECH)

Title: "Emergent AdS$_{d+1}$ Geometry from Functional Renormalization Group"

Abstract: We present a holographic dual description for the O(N) vector model in d dimensional Euclidean space within the functional renormalization group (FRG) frame work. Byiterating Wilsonian renormalization group transformations, the extra-dimensional scale coordinate is identified as the radial direction of an emergent (d+1)-dimensional bulk spacetime. We construct a bidirectional holographic dictionary that maps non-perturbative fluctuations to the emergent bulk metric warping factors. Under the massless critical configuration, the emergent gravitational vacuum reduces to an Anti-de Sitter (AdS$_{d+1}$) geometry, satisfying the local energy conditions.

Miguel Pino (USACH)

Title: "Three-dimensional gravity and the Dym hierarchy of integrable equations"

Abstract: This talk reviews the construction of a family of boundary conditions for three-dimensional gravity with negative cosmological constant, for which the boundary dynamics are governed by the Dym hierarchy of integrable equations. The construction is based on an expansion of the boundary lapse and shift functions in negative powers of the Brown–Henneaux central charge, which plays a role analogous to that of a spectral parameter. The infinite tower of conserved quantities of the Dym hierarchy becomes a set of canonical generators of large gauge transformations, forming an abelian asymptotic symmetry algebra. In addition, the two compatible Hamiltonian structures of the hierarchy arise directly from the gravitational evolution equations.

Finally, a new family of stationary black-hole solutions associated with the first non-trivial member of the hierarchy is presented. By combining the holonomy conditions of the Chern–Simons formulation with periodic solutions of the stationary Dym equation, one obtains black holes that are generically non-axisymmetric and characterized by two continuous parameters, two integer modes, and a relative phase.

Omar Valdivia (UNAP)

Title: ""

Abstract: 

Coffee Break

Nelson Merino (UNAP)

Title: "The KBL regularization and its applications"

Abstract: The Katz boundary term provides a well-defined variational principle under Dirichlet boundary conditions and, when combined with a subtraction of the action evaluated on a background, known as the KBL regularization procedure, yields finite Noether charges and a finite on-shell action. This boundary term is constructed from the dynamical metric and the difference between the Christoffel symbols associated with the dynamical manifold and a reference background. So far, this method has been tested only for specific solutions. In this work (soon to be submitted for publication), using the Fefferman-Graham gauge, we show that the finiteness of conserved charges can be proven for families of asymptotically locally Anti–de Sitter spacetimes in general relativity. The finiteness of the charges can be established in arbitrary dimensions; however, the prescription for defining the background in this framework distinguishes between even and odd spacetime dimensions. Other possible applications and potential relations with the covariant phase space method will also be discussed. 

Hyun Seok Yang (GIST)

Title: "Three-dimensional Gravity and Thurston Geometry"

Abstract: We review the Chern-Simons gauge theory formulation of three-dimensional gravity. Thurston’s conjecture proved by Perelman states that three-manifolds with a given topology have a canonical decomposition into eight manifolds with high symmetry—the so-called Thurston geometries. We address how to formulate the Thurston geometries in terms of the Chern-Simons gauge theory and discuss their boundary conformal field theories.

Carlos Marat Reyes (UBB)

Title: "New constraints on modified gravity with dimension-six operators from gravitational waves"

Abstract: We study gravitational-wave propagation in the presence of dimension-6 higher-derivative operators that break spacetime symmetries within the gravitational Standard-Model Extension. After linearizing the theory, we derive modified dispersion relations and distinguish between nonbirefringent and birefringent sectors. Using multimessenger observations from GW170817/GRB170817A and the binary black-hole event GW150914, we place constraints on the corresponding dimension-6 coefficients, providing new tests of standard linearized gravity.

Spyros Sypsas (UBB)

Title: "Pushing the Primordial Frontier: Exact Linear Solutions in Multifield Inflation"

Abstract: We present exact analytic solutions for the linear dynamics of a two-field inflationary system. The solutions are valid for arbitrary values of masses and the dimensionless bilinear interaction strength, within a quasi-de Sitter background. They therefore provide analytic control over the strongly coupled regime in which the curvature perturbation interacts with light isocurvature fields, commonly associated with rapid-turn inflation. As a first application, we derive the amplitude of the primordial power spectrum in closed form, obtaining an expression that interpolates between the weakly coupled, strongly coupled, light-field, and heavy-field regimes. These results open the way to analytic studies of multifield observables beyond the power spectrum, including non-Gaussianity, particle production, and loop corrections.

Jorge Zanelli (CECs - USS)

Title: ""

[Abstract: TBA]

Break / Transition

Lunch

Daniele Bielli (APCTP)

Title: "The classical Yangian symmetry of Auxiliary Field Sigma Models"

Abstract: Yangian algebras are infinite-dimensional extensions of Lie algebras which often encode the hidden symmetries underlying integrable quantum field theories.

Classical counterparts of these structures have also been shown to arise in certain examples of classically integrable systems, such as 2d Principal Chiral and Symmetric-Space sigma models.

We discuss the emergence of classical Yangians in various infinite families of 2d sigma models deformed via auxiliary fields, by generalising the Brezin, Itzykson, Zinn-Justin, and Zuber (BIZZ) construction of non-local conserved charges and deriving necessary conditions for a broad class of associated current algebras to give rise to a Yangian.

Marco Biachi (USS)

Title: "Exact Results and New Computational Methods in Quantum Field Theory"

Abstract: I will review recent work on exact observables in supersymmetric quantum field theories, focusing on Wilson loops, localization, and holography. I will also discuss emerging computational approaches, including quantum algorithms and machine learning, for tackling increasingly complex calculations.

Poster session & Talk Refreshments