Iberian Strings 2019

Contribution List

5. The Generalized Supergravity Equations

Linus Wulff

23/01/2019, 09:15

I will review how requiring kappa symmetry for the Green-Schwarz string in a general background leads to a generalization of the usual equations of supergravity. These generalized supergravity equations can also be interpreted as scale invariance, as opposed to Weyl invariance, conditions for the string sigma model. Non-trivial solutions to these equations can be generated by anomalous...

6. Supersymmetric Action for Multiple D0-brane System

Igor Bandos

23/01/2019, 10:15

We present a complete action for the system of N D0-branes in flat 10D type IIA superspace. It is invariant under the rigid spacetime supersymmetry and local worldline supersymmetry (kappa--symmetry). This latter can be considered as supersymmetry of maximal 1d SU(N) SYM model which is made local by coupling to supergravity induced by embedding of the center of energy worldline into the target...

7. (Super) Maxwell Symmetries and Infinite Dimensional Algebras

Joaquim Gomis

23/01/2019, 11:15

The Poincaré algebra can be extended (non- centrally) to the Maxwell algebra and beyond. These extensions are relevant for describing particle dynamics in electro-magnetic backgrounds. They also appear in gravity theories. We establish the relation of this construction to Free Lie algebras. We will also consider the supersymmetric extension and the role of Free super Lie algebras and Borcherds...

8. Quantum Gravity from Timelike Liouville

Teresa Bautista Solans

23/01/2019, 11:45

The Euclidean path integral of quantum gravity has long resisted a proper definition because the kinetic term for the conformal factor of the metric comes with an additional minus sign. We propose a definition of two-dimensional quantum gravity with a cosmological constant based on the conformal bootstrap results of timelike Liouville theory coupled to matter. For the spectrum, we prove a...

9. CYBE/Gravity Correspondence: Vision & Reality

Eoin Ó Colgáin

23/01/2019, 12:15

Building on integrable deformations of sigma-models, we outline a map between deformations of generic supergravity solutions and solutions to the Classical Yang-Baxter Equation. Time permitting, we will touch upon TTbar deformations.

10. How to Build the Thermofield Double State

Diego Hofman

23/01/2019, 14:30

Given two copies of any quantum mechanical system, one may want to prepare them in the thermofield double state for the purpose of studying thermal physics or black holes. However, the thermofield double is a unique entangled pure state and may be difficult to prepare. We propose a local interacting Hamiltonian for the combined system whose ground state is approximately the thermofield double....

11. The Fate of Pseudo-Weyl Invariance

Raquel Santos

23/01/2019, 15:30

In the context of studying Unimodular Gravity (UG), it is useful to consider a more general scalar-tensor theory obtained from the General Relativity (GR) lagrangian by the process of group averaging. Such theory inherits the diffeomorphism invariance of GR but has a tautological Weyl invariance. This theory can reduce both to GR and UG depending on the gauge fixing choice for the conformal...

12. Recent Results on Alpha Prime Corrections of Stringy Black Holes

Tomás Ortín

23/01/2019, 16:30

I will review some recent results on the explicit computation of the first-order alpha prime corrections of static, supersymmetric 4- and 5-dimensional stringy black holes. We will use the framework of the Heterotic Superstring effective action and we will study the corrections to entropy of those black holes and we will compare it to the microscopic computations in the literature. We will...

13. The Small Black Hole Illusion

Pedro F. Ramirez

23/01/2019, 17:00

Small black holes in string theory are characterized by a classically singular horizon with vanishing Bekenstein-Hawking entropy. For decades, it was thought that higher-curvature corrections resolve the horizon and that the associated Wald entropy is in agreement with the microscopic degeneracy. In this talk I will argue that such resolution is an illusion, which involves a misidentification...

14. Exact results and microstate counting formulae for BPS black holes in the N=2 STU model

Gabriel Lopes Cardoso

23/01/2019, 17:30

We consider the N=2 STU model of Sen and Vafa. Using its exact duality symmetries, we determine the holomorphic function F that encodes the Wilsonian effective action of the model. We then evaluate the quantum entropy for dyonic BPS black holes in this model, in a certain region of moduli space. We propose a microstate counting formula based on a Siegel modular form of weight 2 as well as on a...

15. Probing typical black hole microstates

Kyriakos Papadodimas

24/01/2019, 09:15

Understanding the geometry of a typical microstate of a large AdS black hole remains an outstanding open problem, which is closely connected to the black hole information paradox. In this talk I will present a proposal for the bulk geometry of typical states. I will discuss how state-dependent perturbations of the CFT Hamiltonian can be used to implement a 1-sided analogue of the...

16. Quantum (Super)gravity from Conformal Field Theory

Francesco Aprile

24/01/2019, 10:15

Using knowledge about the spectrum of operator in N=4 SYM, consistency of OPE, and analytic bootstrap techniques, I will obtain loop corrections of IIB supergravity on AdS_5\timesS^5. Along the way, I will discuss a general formula for the leading anomalous dimension of all double trace operators in the supergravity regime.

17. A Quantum Mechanical Model for Holography

Troels Harmark

24/01/2019, 11:15

Talk about recent work done in 1810.05560 "Strings with non-relativistic conformal symmetry and Limits of the AdS/CFT correspondence."

18. Gravity and Holography Between Newton and Einstein

Niels Obers

24/01/2019, 11:45

Newton-Cartan geometry was introduced more than 90 years ago in order to find a geometric formulation of Newtonian gravity. This geometry (including a novel generalisation that includes torsion) has in recent years gained renewed interest as it appears in a variety of settings in modern theory involving gravity, string theory and holography. After a brief introduction, I will talk about recent...

19. A Geometric Dual of C-Extremization

Christopher Couzens

24/01/2019, 12:15

We consider a class of supersymmetric AdS_3 x Y_7 solutions of Type IIB supergravity holographically dual to 2d (0,2) SCFTs. We show that the R-symmetry and central charge may be computed by extremizing a certain functional depending on only global topological data. In particular, assuming such a solution exists, we may calculate its central charge without knowledge of an explicit metric. We...

20. Large Mass Hierarchies in Strongly Coupled Field Theories from Gauge-Gravity Duality

Daniel Elander

24/01/2019, 14:30

Strongly coupled theories exhibiting walking dynamics provide a scenario for beyond the Standard Model physics, in which electro-weak symmetry is broken dynamically and the large hierarchy between the electro-weak and Planck energy scales is naturally generated. Due to the spontaneous breaking of approximate scale invariance, a light dilaton can be expected to be present in the spectrum. In...

21. A Supersymmetric Color Superconductor from Holography

Javier Tarrio

24/01/2019, 15:00

N=4 SYM, and deformations thereof, is a model giving rise to a vast number of explicit examples of strong coupling phenomena via holography. In this talk I will consider probing the system with fundamental matter, focusing on a phase at finite isospin density and low temperatures. The ground state consists of a supersymmetric Higgsed phase with spontaneously broken global symmetries, which...

22. Phonon Emergence

Daniele Musso

24/01/2019, 16:00

Phonons are essential constituents of almost every condensed matter model, yet their dynamical origin is never described. The emergence of phonons from a spatially-modulated order parameter is arguably the best candidate mechanism to explain the anomalous resistivity of strongly-correlated electron systems. The description of the translation-breaking dynamics defines a novel type of...

23. The 10d Physics of the GPPZ Flow and Confinement in N=1* Super-Yang-Mills

Ben Niehoff

24/01/2019, 16:30

I will discuss the recent uplift to 10 dimensions of the 5d flow solution of Girardello, Petrini, Porrati, and Zaffaroni (GPPZ). By analyzing the 10d solution, I will show how the GPPZ singularity can be given a 10-dimensional interpretation in terms of 3-branes and 5-branes. Using this interpretation, I will make the connection to N=1* super-Yang-Mills and the Polchinski-Strassler vision of...

24. Anisotropic RG Flows, Black Holes and Holography

Juan Pedraza

24/01/2019, 17:00

In this talk, I will describe a new set of anisotropic, non-conformal and confining gauge theories that are holographically realized in gravity by Einstein-Axion-Dilaton systems. In the vacuum, the new solutions describe RG flows from a conformal field theory in the UV to generic scaling solutions in the IR with generic hyperscaling violation and dynamical exponents θ and z. At finite...

25. A Landscape of de Sitter Vacua?

Mariana Graña

25/01/2019, 09:15

The recent swampland conjectures have revived the long-standing debate about whether string theory supports a landscape of de Sitter vacua. After reviewing the KKLT construction of de Sitter solutions, which is at the core of the landscape paradigm, I will show in this talk the recent and not so recent ten-dimensional calculations pointing out problems in the string theory construction.

26. Low Energy Constraints from Quantum Gravity

Alvaro Herraez

25/01/2019, 10:15

The requirement that a theory can be consistently coupled to Quantum Gravity can have an impact on low energy physics. After a brief introduction to the so called Swampland Conjectures, which aim to determine the set of EFT that can be consistently completed into to a Quantum Gravity theory, we will focus on some implications of a refined version of the Weak Gravity Conjecture, which states...

27. Universality of Squashed-Sphere Partition Functions

Pablo Cano

25/01/2019, 11:15

According to the AdS/CFT correspondence, Conformal Field Theories on squashed spheres are dual to AdS-Taub-NUT geometries in the bulk. By studying novel Taub-NUT solutions in a broad family of higher-curvature gravities, we are able to derive universal relations for the partition function of these CFTs. First, we propose a new formula that automatically computes the free energy in terms of the...

28. M2- Brane on a Flux Background

Maria Pilar Garcia del Moral

25/01/2019, 11:45

I will present recent results about supermembrane theory formulated in the presence of constant three form subject to a Target space flux condition. I will show the discreteness of its spectrum that makes it to be well- defined at quantum level. I will discuss about the connection between Target space fluxes and worldvolume fluxes. I will also comment about the relation with matrix models on...

29. Collisions in AdS and the Quantum Null Energy Condition

Wilke van der Schee

25/01/2019, 12:15

In this talk I will give an introduction to the Quantum Null Energy Condition (QNEC), which is a unique local energy condition conjectured to be valid for any QFT. QNEC relates the normal null energy condition (NEC) with the second functional null derivative of the entanglement entropy and was inspired from the second law of black hole thermodynamics, even though it is valid in QFTs without...

30. Calibrated Entanglement Entropy

Nihat Sadik Deger

25/01/2019, 14:30

The Ryu-Takayanagi prescription reduces the problem of calculating entanglement entropy in CFTs to the determination of minimal surfaces in a dual anti-de Sitter geometry. For 3D gravity theories and BTZ black holes, we identify the minimal surfaces as special Lagrangian cycles calibrated by the real part of the holomorphic one-form of a spacelike hypersurface. We show that (generalised)...

31. Singularity Theorems and the Stability of Extra Dimensions

Jose M M Senovilla

25/01/2019, 15:00

New singularity theorems are derived for generic warped-product spacetimes of any dimension. The main purpose is to analyze the stability of (compact or large) extra dimensions, such as those arising in string theory, against dynamical perturbations. To that end, the base of the warped product is assumed to be our visible 4-dimensional world, while the extra dimensions define the fibers....

32. Black Hole Interiors and Modular Inclusions

Ro Jefferson

25/01/2019, 16:00

We argue that the traversable wormhole induced by a double-trace deformation of the thermofield double state can be understood as a modular inclusion of the algebras of operators. The effect of this deformation is the creation of a new region of spacetime deep in the bulk, corresponding to a non-trivial center between the left and right algebras. This set-up provides a precise framework for...

33. Geometric Inflation

Jose Edelstein

25/01/2019, 16:30

We argue that the presence of an inflationary epoch is a natural, almost unavoidable, consequence of the existence of a sensible effective action involving an infinite tower of higher-curvature corrections to the Einstein-Hilbert action. No additional fields besides the metric are required. We show that a family of such corrections giving rise to a well-posed cosmological evolution exists and...