TALKS
Luis Guajardo
Title: Black string spectrum of shift-symmetric Horndeski theories
Abstract: In the present work, we study four-dimensional black strings in Horndeski models with translation invariance. Imposing that the scalar field depends on the string-generator coordinate, the Klein-Gordon equation admits a linear profile as a solution. This relaxation allows finding rotating, asymptotically AdS$_3\times \mathbb{R}$ black strings, dressed with an effective cosmological constant. In this regard, we show that in the full spectrum of shift-symmetric Horndeski theories with Einstein limit, the scalar charge needs to be fixed in terms of the parameter space. This method is employed to concrete examples to illustrate the scheme we go along with. Regarding the conserved charges, we compute them via the Euclidean method and show the fulfillment of the associated Smarr Law. Finally, we exhibit that our AdS strings are locally and globally stable under small fluctuations around the equilibrium.
Ricardo Stuardo
Title: Dualities of 3D N=1 SQCD from Branes and non-SUSY deformations
Abstract: We study the dynamics of an 'electric' N=1 3D U(Nc) level (k,k+Nc/2) SQCD theory. By embedding the theory in string theory, we propose that the theory admits a 'magnetic' dual and analyse the low energy dynamics of the theory using its dual. When Nf≥Nc−2k the IR dynamics is described by either a TQFT for large quark masses, or a Grassmanian and a Wess-Zumino (WZ) term for small masses. We also consider non-supersymmetric mass deformations and RG flows in the vicinity of the SUSY point and find agreement between the IR of the electric and its magnetic dual. When Nf<Nc−2k supersymmetry is broken and the IR dynamics is a described by a TQFT accompanied by a Goldstino. We also discuss SQCD theories based on SO/USp gauge groups.
Felipe Díaz-Jaramillo
Title: Gauge Independent Kinematic Algebra of Self-Dual Yang-Mills
Abstract: In this talk, I will discuss certain topics relevant to a relation between Yang-Mills theory and gravity called the double copy, which was first formulated in the context of scattering amplitudes. Scattering amplitudes in Yang-Mills theory contain information about color in the form of color factors constructed with elements of a color Lie algebra, and information about kinematics encoded in so-called kinematic numerators that depend on polarization vectors and momenta. The double copy states that, provided that certain algebraic conditions are met, exchanging the color information by kinematic information in Yang-Mills scattering amplitudes leads to amplitudes in gravity. The algebraic considerations involved in the double copy suggest that there is a so-called kinematic algebra underlying the kinematics of Yang-Mills, analogous to how color is encoded in a Lie algebra. In particular, the first explicit realization of a kinematic algebra was found for the self-dual sector of Yang-Mills after imposing a light-cone gauge condition and partially solving the field equations. The kinematic algebra in this case was found to be the Lie algebra of area-preserving diffeomorphisms. In this talk, I will show that, before gauge fixing and partially solving the field equations, there exists a larger kinematic algebra in the self-dual sector of Yang-Mills that is not a Lie algebra, but rather a special type of homotopy algebra. This algebra is independent of the choice of gauge and, upon imposing light-cone gauge, one recovers the Lie algebra of area-preserving diffeomorphisms. This type of kinematic homotopy algebras has also been found in pure Yang-Mills and Chern-Simons theories.
Valentin Benedetti
Title: Generalized Symmetries and Noether currents
Abstract: We will study how the presence of generalized symmetries in a theory is related, from a local QFT point of view to the emergence of Haag duality violating (HDV) operator classes. In this context, we explain that if the non-local operators associated with the generalized symmetries transform under the action of a continuous global symmetry group then there cannot be a well-defined Noether current for such a group. Furthermore, if generalized symmetries are charged under such a continuous global symmetry, they must be generated by a continuous of non-commuting dual HDV classes. If the HDV classes form a non-compact group, then we find that a theory with an unbroken non-compact higher-form symmetry is necessarily massless and free. However, if the HDV group is compact, the presence of charged classes seems compatible with an interacting QFT. The prototypical example is the chiral symmetry in QFT violated by the presence of the Adler-Bell-Jackiw anomaly. We will show how to understand the anomaly as a full abelian U(1) symmetry generated by a non-gauge-invariant Noether current. This entails the construction of the U(1) symmetry transformations for arbitrary, topologically non-trivial, spacetime regions, and showing they can transform the non-local charges.
César Díaz
Title: Complexity of magnetization and magnetic simplification
Abstract: We use the Complexity=Volume (CV) prescription to study the effect of a magnetic field on the holographic complexity of formation for states in the gauge theories dual to two different gravitational models. In one of these theories the complexity increases with the intensity of the magnetic field, while in the other a more interesting behavior is discovered, resulting in a phenomenon that we term magnetic simplification. The relevant difference between the two theories is that the content of the second includes a scalar operator with a non-vanishing vacuum expectation value. This leads us to conclude that the direct impact of the magnetic field is to increase the complexity of formation of a state, but it can indirectly lower it by diminishing the complexity associated to additional degrees of freedom when these do not vanish across the space.
Mairym Busnego-Barrientos
Title: Conformal Renormalization of scalar-tensor theories
Abstract: We study a conformally coupled scalar-tensor theory with a quartic potential possessing local conformal symmetry up to a boundary term. We show that requiring the restoration of the full local conformal symmetry fixes the counterterms that render the on-shell action finite. The building block of the resulting action is a conformally covariant tensor which is constructed out of the metric and the scalar field and it has the same conformal weight as the Weyl tensor. This allows us to obtain the counterterms for the scalar-tensor sector in a closed form. The finiteness of the conformally complete version of the action is suggestive on the validity of the \emph{Conformal Renormalization} prescription. We extend this theory by adding the Conformal Gravity action and also the Einstein-AdS action written in MacDowell-Mansouri form. Even though the latter breaks the conformal symmetry, we find that the action is still renormalized provided a suitable falloff of the scalar field when considering asymptotically locally anti-de Sitter solutions. Black hole solutions in these theories are studied, for which the Hawking temperature and the partition function to first order in the saddle-point approximation are calculated, providing a concrete example of this renormalization scheme.
Anthonny Freddy Canazas Garay
Title: Interpolating Wilson loops in ABJM, boundary conditions on AdS2 and 1D conformal symmetry
Abstract: Motivated by the existing supersymmetric ABJM Wilson loops one-parameter family that interpolates between the 1/2-BPS fermionic and the 1/6-BPS bosonic ones, we look at the string excitations around an AdS2 ⊂ AdS4 × CP3 worldsheet. In this way, we obtain correlators of operators inserted along a 1D defect. Considering two kinds of boundary conditions for massless scalars on AdS2 that interpolate between the Dirichlet and Neumann cases while preserving scale invariance, these 2- and 4-point correlators are computed holographically.
GONG SHOW
Maximiliano Gabriel Ferro
Title: Correlators on ABJ(M) line-defects from string worldsheet on AdS4 × CP3: The role of Kalb-Ramond background
Abstract: One of the two prototypical examples of the AdS/CFT correspondence is the ABJM model which establishes the equivalence between N = 6 super Chern-Simons with gauge group U(N) x U(N) with type IIA string theory in the AdS4 x CP3. This model admits a simple and interesting generalization known as the ABJ model where the gauge group in the Chern-Simons theory is taken to be U(M) x U(N). The dual string theory description must include a flat Kalb-Ramond field, having a non-trivial holonomy on a non-contractible cycle CP1 ⊂ CP3. In every gauge theory, Wilson Loops are interesting observables useful for characterizing many features of the theory. In supersymmetric theories, there are available generalizations of this kind of non-local observables, namely BPS-Wilson Loops, which preserve some amount of supercharges. In some cases, the vacuum expectation value of these operators is protected from quantum corrections by supersymmetry. Such BPS-Wilson operators provide interesting one-dimensional defect CFTs supported on the three-dimensional theory. At strong coupling, the defect CFT1 is encoded into the degrees of freedom of a semiclassical open string, when a gauge/gravity description is available, as in our case. We study the ⅙ BPS Wilson Line in ABJ theory, which corresponds to AdS2 string worldsheet with Neumann boundary conditions on a CP1 subspace of the CP3 geometry. In this case, the open string is coupled to the B-field, changing the boundary conditions over the AdS2 fields and leading to modified propagators. From non-perturbative arguments, the scale invariance on this line defect is guaranteed, but from a perturbative point of view, the full conformal invariance is far from obvious. In this context, we try to check the conformal invariance of 4-point correlators on this line-defect explicitly from Witten diagrams at 2-loops.
Rodrigo González Quaglia
Title: Reheating constraints to Starobinsky Inflation
Abstract: The Starobinsky model for inflation has been widely studied both for its simplicity and great agreement with experimental data. In this talk we plan to further study this model by employing the slow roll methodology without any further approximation. Expressions relating the cosmological quantities like the number of e-fold of inflation with measurable quantities like the spectral index and the tensor to scalar ratio are found. Furthermore, by linking the reheating epoch with the inflationary one, we show how to impose new bounds for the Starobinsky's inflation observables using the previously found relations.
Marcelo Oyarzo
Title: An holographic perspective of a (1+1) confining field theory
Abstract: This talk is about the holographic point of view of a field theory on the intersection of two stacks of D5 branes. The holographic dual background has an IR singularity. We solve this singularity by compactifiying the theory on a circle, preserving 4 supercharges. Various aspects of the QFT are studied such as: confinement, symmetry breaking, entanglement entropy, among others. I will also discuss a black hole solution obtained by a double wick rotation of the original configuration.
Juan Ramos
Title: Wilson lines construction of sl3 toroidal conformal blocks.
Abstract: In this talk we will talk about W3 toroidal conformal blocks for degenerate primary fields in AdS/CFT context. In the large central charge limit W3 algebra reduces to sl3 algebra and sl3 blocks are defined as contributions to W3 blocks coming from the generators of sl3 subalgebra. We consider the construction of sl3 toroidal blocks in terms of Wilson lines operators of 3D Chern-Simons gravity in the thermal AdS3 space-time. According to the correspondence, degenerate primary fields are associated with Wilson lines operators acting in the corresponding finite-dimensional sl3 representations. We verify this dual construction for one-point toroidal block using sl3 tensor technique in the bulk theory and an algorithm based on AGT correspondence in the boundary CFT. The talk is based on the work: arxiv: 2301.04575.
Francisco Reyes Zurita
Title: 1/c deformations of AdS3 boundary conditions
Abstract: The novel connection between the asymptotic dynamics of 2+1 dimensional General Relativity with integrable systems has been studied recently due the possibility to explore holography beyond conformal symmetry. In this regard, we construct a set of suitable boundary conditions for the gravitational field which deforms those of Brown-Henneaux using negative powers of the central charge. Through a recursive method, we construct a novel infinite tower of conserved charges in involution under Poisson bracket. The boundary dynamics corresponds to equations belonging to the Harry Dym hierarchy.
Matías Nicolás Sempé
Title: The language of de Sitter: Group theory
Abstract: In this talk we will discuss how SO(D,1) group properties help us characterize the behavior of gauge fields in de Sitter and what do we see in future infinity where the CFT should be.
Luis Fernando Temoche
Title: Love Numbers for Rotating 5D Black Holes
Abstract: We introduce the concepts of static response coefficients and scalar tidal Love Numbers for black holes. In 4 dimensions, Love Numbers are known to vanish regardless of the mass and spin of the black hole. Is this still true in higher dimensions? As an initial exploration, we focus on the 5D cases and present our results obtained for both the Myers-Perry and Black Ring solutions. Finally, we address the relations found with lower dimensional cases known in the literature.