# THE STRING THEORY UNIVERSE - 22nd European string workshop and Final COST MP1210 Conference

Europe/Rome
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#### Other Institutes

Università degli Studi di Milano - Bicocca INFN Sezione Milano - Bicocca Piazza della Scienza 3 - U2 20126 Milan Italy
Description

This is the final conference of the COST Action MP1210 The String Theory Universe. It will also continue the long-standing tradition of the annual European Workshop in String Theory and related topics, coinciding with the "XXII European Workshop on String Theory''. The scientific content will reflect the research activities of EU groups participating in the Action, which have been organized in Working Groups. Main subjects will cover gauge/gravity correspondence (fundaments and applications), string phenomenology and black holes, quantum gravity and quantum information. The Conference will provide an overview on the main recent developments in these subjects together with the main results, achievements and innovative mathematical tools that have been developed in the four-year duration of the Action.

Overview and discussion sessions will be organized, led by the Working Group leaders

Johanna Erdmenger (Max-Planck-Institut für Physik, Munich) - WG1

Michela Petrini (Sorbonne Universites UPMC Paris 06) - WG2

Roberto Emparan (ICREA & Universitat de Barcelona) - WG3

A special session led by WG5 leader Marian Lledò will be devoted to the discussion of the effectiveness of gender activities already organized by the Action and future perspectives.

Among invited speakers

Ofer Aharony (Department of Particle Physics and Astrophysics, Weizmann Institute)

Gianguido Dall’Agata (Dipartimento di Fisica, Università di Padova)

Jan de Boer (Institute of Physics, Universiteit van Amsterdam)

Geoffrey Compère (Département de Physique, ULB)

Simone Giombi (Physics Department, Princeton University)

Chris Hull (Blackett Laboratory, Imperial College)

Romuald A. Janik (Institute of Physics, Jagiellonian University)

Jan Louis (Institut für Theoretische Physik, Universität Hamburg)

Sameer Murthy (Department of Mathematics, King’s College)

Alessandro Naga(Institut des Hautes Études Scientifiques, Bures-sur-Yvette)

Henning Samtleben (Laboratoire de Physique, University of Lion)

Sakura Schafer-Nameki (Mathematical Institute, Oxford University)

Marika Taylor (STAG and Mathematical Sciences, University of Southampton)

Local organizers: Dietmar Klemm (Unimi), Andrea Mauri, Sara Pasquetti, Silvia Penati, Paul Richmond, Alberto Santambrogio (INFN - Milano), Alessandro Tomasiello, Alberto Zaffaroni

Scientific committee: Micha Berkooz, Anna Ceresole, Roberto Emparan,  Johanna Erdmenger, Matthias Gaberdiel, Jerome Gauntlett, Gabriele Honecker, Marian Lledò, Yolanda Lozano, Michela Petrini, Antoine Van Proeyen.

Payment info:

Account holder: Università degli Studi di Milano - Bicocca (UNIMIB)

IBAN account number: IT87 K056 9601 6280 0000 0200 X71

Bank SWIFT/BIC code: POSOIT22XXX

Bank name: Banca Popolare di Sondrio

in the reason for payment please insert the code MP1210 and your name.

Participants
• Abhiram Mamandur Kidambi
• Achilleas Passias
• Aldo Cotrone
• Alessandra Gnecchi
• Alessandro Nagar
• Alessandro Torrielli
• Alessio Marrani
• Ali Seraj
• Ana Achucarro
• Andre Coimbra
• Andrea Campoleoni
• Andrea Galliani
• Andrea Legramandi
• Andrea Marini
• Andrea Marzolla
• Andrea Mauri
• Anna Ceresole
• Anthony Ashmore
• Antoine Van Proeyen
• Anton Nedelin
• Antonio Amariti
• Arash Ranjbar
• Bianca Letizia Cerchiai
• Binaya Kumar Bishi
• Bivudutta Mishra
• Blagoje Oblak
• Carlos Shahbazi
• Carolina Valeria Gomez
• Charles Strickland-Constable
• chiara toldo
• Chris Blair
• Chris Hull
• Christian Ecker
• Damian Galante
• Daniel Fernandez
• Daniel Junghans
• Daniela Herschmann
• Daniël Prins
• David Rodríguez
• David Turton
• Davide Cassani
• Debajyoti Sarkar
• Dieter Lüst
• Dieter Van den Bleeken
• Dmitri Sorokin
• Domenico Seminara
• Dujin Ahn
• Edoardo Lauria
• Eirik Eik Svanes
• Emanuel Malek
• Emine Seyma Kutluk
• Erik Plauschinn
• Fabio Apruzzi
• federica crespi
• Flavio Porri
• Fotis Farakos
• Francesca Ferrari
• Francesco Azzurli
• Francesco Bigazzi
• Francisco Pena-Benitez
• Frederic Brünner
• Gabriel Cardoso
• Gabriele Honecker
• Gabriele Lo Monaco
• Gabriele Tartaglino Mazzucchelli
• Gautier Solard
• Geoffrey Compere
• Georgios Linardopoulos
• Gianguido Dall'Agata
• Gianluca Grignani
• Gianluca Inverso
• Giuseppe Bruno De Luca
• Gustavo Lucena Gómez
• Henning Samtleben
• Hyun-Sik Jeong
• Jan de Boer
• Jan Louis
• Javier Tarrio
• Jay Armas
• Jerome Gauntlett
• Jesus Montero
• Jia-ju Zhang
• Jie Ren
• Johanna Erdmenger
• Joseph Novak
• Kiril Hristov
• Laura Andrianopoli
• Lilia Anguelova
• Lorenzo Menculini
• Luca Cassia
• Luca Griguolo
• Lucrezia Ravera
• Magdalena Larfors
• Mahdis Ghodrati
• Manus Visser
• Marco Fazzi
• marco rabbiosi
• Marco Sanchioni
• Marco Scalisi
• Marek Szydlowski
• Maria A Lledo
• Maria Pilar Garcia del Moral
• Marialuisa Frau
• Marika Taylor
• Massimo Taronna
• Matteo Bertolini
• Matthias Gaberdiel
• Micha Berkooz
• Michela Petrini
• Miguel Costa
• Mikel Berasaluce González
• Natalia Pinzani Fokeeva
• Niall Macpherson
• Niccolò Cribiori
• Nicolo' Piazzalunga
• Nicolò Petri
• Niels Obers
• Ofer Aharony
• Oscar de Felice
• Oscar Lasso Andino
• Pablo Antonio Cano
• Pablo Bueno
• Panagiota Kanti
• Panagiotis Betzios
• PARBATI SAHOO
• PARBATI SAHOO
• Paul Richmond
• Pedro F. Ramirez
• Pierre Corvilain
• Pietro Antonio Grassi
• Pietro Benetti Genolini
• Pietro Longhi
• Pil-Jong Jung
• Praxitelis Ntokos
• Raffaele Marotta
• Riccardo Argurio
• Roberto Emparan
• Rodrigo Olea
• Romuald Janik
• Sakura Schafer-Nameki
• Sameer Murthy
• Samuele Chimento
• Sara Bonansea
• Sayantan Choudhury
• Sayantan Choudhury
• Sergio Benvenuti
• Sergio Camilo Vargas Avila
• Seyed Morteza Hosseini
• Silvia Penati
• Simone Giacomelli
• Simone Giombi
• Souvik Dutta
• Spyridon Talaganis
• Stanislav Schmidt
• Stefan Prohazka
• Stefan Vandoren
• Stefano Baiguera
• Stefano Speziali
• Stephane Detournay
• Svetlana Pacheva
• Tassos Petkou
• Thomas Van Riet
• Timm Wrase
• Tobias Zingg
• Tomás Ortín
• Tuna Demircik
• Valentin Reys
• Valentina Forini
• Victor Lekeu
• Wataru Ichinose
• Yegor Korovin
• Yolanda Lozano
• YongJun Ahn
• Yun-Long Zhang
• Monday, February 20
• Registration
• 1
WELCOME
• 2
PLENARY TALK 1 - Ofer Aharony

Loops in AdS from conformal field theory

"Gauge/gravity duality is often used to compare classical results on the gravity side to leading large-N results in quantum field theory. At higher orders,perturbative loop corrections to the classical gravity results map to 1/Ncorrections to the field theory. We show how crossing symmetry constrains thismapping, and allows a direct conformal field theory computation of loop diagramsin anti-de Sitter space."

• 10:20 AM
Coffee break
• 3
INVITED TALK 1: Jerome Gauntlett

Title: Black Holes and Thermoelectric Transport

In seeking possible applications of holography to real materials the thermoelectric conductivity is an important observable to study. Like the entropy we explain how the DC conductivity can be obtained in terms of the behaviour of black hole spacetimes purely at the horizon. More precisely, we show that the DC conductivity can be obtained by solving a generalised set of Navier-Stokes equations for a fluid living on the black hole horizon. Unlike other connections between fluids and black holes, this is an exact result. We discuss the new extension from two derivative theories of gravity to higher derivative theories.?We also show that CFTs (not just holographic) with spatially periodic temperature gradients and strains can exhibit the novel phenomenon of thermal backflow, in which heat currents locally flow in the opposite direction to that of an applied DC source.

• 4
Talk 1: Natalia Pinzani Fokeeva

Title: Dissipative hydrodynamics from effective field theory

I will provide a first principle formulation of an effective field theory for hydrodynamics. The key feature is the underlying Schwinger-Keldysh partition function and its symmetries which can be implemented using superspace techniques. I will also show how a conserved entropy current arises naturally in this formalism.

• 5

Title: AdS_2 holography and non-extremal black holes

I will present aspects of AdS_2 holography for a specific Einstein-Maxwell-Dilaton model that is obtained by Kaluza-Klein reduction from pure AdS_3 gravity with negative cosmological constant. In particular, I will derive the one-dimensional holographic dual for both running and constant dilaton solutions, and I will discuss the connection with the Sachdev-Ye-Kitaev model. Finally, I will explain how this dilaton gravity model provides a holographic description for four-dimensional asymptotically conformally AdS_2 x S^2 non-extremal black holes. The talk is based on the recent paper https://arxiv.org/abs/1608.07018. NOTE: Topic of talk may change

• 6

Title: Thermalisation of holographic Schwinger-Keldysh correlation functions

Although time-dependence of one-point functions such as the energy-momentum tensor (eg. evolution towards hydrodynamic behavior) is well studied in holography, much less is known about nonequilibrium time-evolution of n-point holographic correlations. We will present simple methods for studying the time-evolution of unequal-time commutators and anti-commutators of local operators (i.e. study their dependence on their average time coordinate) in holography for arbitrary nonequilibrium states. Thermalisation is defined as evolution towards satisfaction of fluctuation-dissipation relation between the Wigner transformed commutator and the anti-commutator, both of which are measurable separately in solid-state and ultracold atomic systems. We will provide evidence that patterns of holographic thermalisation of two-point Schwinger-Keldysh correlations can be classified using parameters analogous to the Reynolds' number used in case of hydrodynamic flows. In a simple example, we will explicitly show that by changing the quenching rate we obtain three different qualitative evolutions. Finally, we will discuss how we can develop quantum kinetic theory at strong coupling from our results using standard methods and propose new experiments.

• Question time
• 12:45 PM
Lunch
• 7
INVITED TALK 2: Matthias Gaberdiel

Title: BPS states in AdS_3 x S^3 x S^3 x S^1

The BPS spectrum of string theory on AdS_3 x S^3 x S^3 x S^1 is determined using a world-sheet description in terms of WZW models. It is found that the theory only has BPS states with j^+ = j^- where j^{\pm} refer to the spins of the two su(2) algebras of the large N=4 superconformal algebra. We then re-examine the BPS spectrum of the corresponding supergravity and find that, in contradistinction to previous claims in the literature, also in supergravity only the states with j^+=j^- are BPS. This resolves a number of long-standing puzzles regarding the BPS spectrum of string theory and supergravity in this background. [This is based on joint work with Lorenz Eberhardt, Rajesh Gopakumar and Wei Li.]

• 8
INVITED TALK 3: Romuald Janik

Title: The String Field Theory vertex, gluing and wrapping

I will review recent work done on the string field theory vertex from integrability emphasizing the relation of the decompactified case to the exact finite volume answer in the case of the pp-wave. I will show parallels with other observables in integrable field theories.

• 3:25 PM
Coffee break
• 9
WG1 OVERVIEW - Johanna Erdmenger

prova

• 10
WG1 Discussion - Chair Johanna Erdmenger
• Tuesday, February 21
• 11
PLENARY TALK 2: Chris Hull

Title: Strings, Fields and Geometry

• 10:20 AM
Coffee break
• 12
INVITED TALK 4: Yolanda Lozano

Title: Linear quivers and non-Abelian T-duals

Non-Abelian T-duality has been very successfully applied in recent years as a solution generating technique in the AdS/CFT context. Its realization in the CFT side of the correspondence remains however still poorly understood. In this talk we will propose linear quivers realized in known brane set-ups as field theory duals of certain AdS backgrounds constructed through non-Abelian T-duality

• 13
Talk 4: Simone Giacomelli

Title: T-branes, monopole operators and S-duality

T-branes are exotic bound states of D-branes, characterized by mutually non-commuting vacuum expectation values for the worldvolume scalars. We study T-branes in M-theory by probing the geometry with an M2-brane, finding that the effect of a T-brane is to deform the membrane worldvolume superpotential with monopole operators. The dynamics of the resulting theory can be studied using a dual description involving conventional superpotential terms and (the dimensional reduction of) class S trinion theories. The S-dual description of N=2 SU(N) SQCD with 2N flavors in four dimensions plays a crucial role in our construction.

• 14
Talk 5: Fabio Apruzzi

Title: 2D theories from F-theory and 6D SCFTs

Compactifications of the physical superstring to two dimensions provide a general template for realizing 2D conformal field theories coupled to worldsheet gravity, i.e. non-critical string theories. Motivated by this, I will describe how to determine the 2D (0,2) theory upon compactification of Heterotic and Type I on a Calabi-Yau fourfold and F-theory on an elliptically fibered Calabi-Yau fivefold. From another point of view, I will also illustrate the 2D theories obtained by 6D SCFTs compactified on a four-manifold, which can be seen as coming from F-theory on a particular class of Calabi-Yau fivefolds. Doing so, one generates a large class of novel 2D quantum field theories. This new prospective will allow us to describe the interacting Largangian and non-Lagrangian sectors of the theory (DGLSM).

• 15

Title: Double Field Theory at SL(2) angles

In this talk I will present an extended field theory that captures the full SL(2) x O(6,6+n) duality group of N=4 supergravity in four dimensions. Making use of the SL(2) structure, I will show how to generate gaugings at SL(2) angles via generalised Scherk-Schwarz ansätze. Such gaugings allow for moduli stabilisation including the SL(2) dilaton.

• Question time
• 12:45 PM
Lunch
• 16
General interest talk - Alessandro Nagar

Title: "Gravitational waves from coalescing compact binaries: interfacing analytical and numerical approaches"

"The direct detection by the LIGO detectors of the gravitational waves emitted by a coalescing black hole binaries (GW150914 and GW151226) has marked the beginning of gravitational wave (GW) astronomy. In the first part of the talk, I will review the recent experimental result and remind the basics elements of gravitational wave theory, focusing on the qualitative structure of the GW signal emitted by a coalescing binary (either made by two black holes or two neutron stars). In the second part of the talk, I will introduce the state-of-the-art analytical effective-one-body (EOB) approach to the general-relativistic two-body dynamics, its completion using numerical relativity (NR) simulations of (spinning) coalescing black hole binaries and its necessity to compute the (thousands of) analytical waveform templates needed for the actual data analysis of GW events like GW150914 and GW151226. Such theoretical interplay between analytical methods and numerical simulations is the key ingredient behind our interpretation of these events as a binary black hole coalescences."

• 17
PLENARY TALK 3: Marika Taylor

Title: New results on non-AdS holography

• 3:55 PM
Coffee break
• 18
INVITED TALK 5: Henning Samtleben

Title: Exceptional field theories and what we can do with them

Exceptional field theories are the manifestly duality covariant formulations of supergravity that have proven powerful in addressing various problems in supergravity theories. I review the framework and the construction of these theories. Among their applications I discuss consistent truncations of (super)gravity, higher dimensional origins of dyonic gauged supergravities, and generalised type II supergravity.

• 19
Gongshow
• Reception - Poster Session
• Wednesday, February 22
• 20
PLENARY TALK 4: Simone Giombi

Title: On the spectrum of CFTs with weakly broken higher-spin symmetry

I will overview some recent results in conformal field theories whose spectrum includes towers of nearly conserved higher spin operators. Examples are bosonic and fermionic vector models in the large N or epsilon expansions. Such models are AdS/CFT dual to higher-spin gravity theories in AdS where the higher-spin symmetry is broken by quantum effects.

• 10:20 AM
Coffee break & Poster Session
• 21
INVITED TALK 6: Jan de Boer

Title: Comments on the spectrum of conformal field theories in d>2

• 22
WG3 OVERVIEW - Roberto Emparan
• 23
WG3 Discussion - Chair Roberto Emparan
• 1:00 PM
Lunch & Posters
• 24
FREE AFTERNOON - Soccer game & Brera Museum visit
• MC MEETING: Meeting reserved to COST MC Members
• Thursday, February 23
• 25
PLENARY TALK 5: Sakura Schafer-Nameki

Title: M5-branes and N=4 with varying Coupling

• 10:20 AM
Coffee break
• 26
INVITED TALK 7: Gabriele Honecker

Title: Deformations, Moduli Stabilisation and Loop-Corrected Gauge Couplings for Particle Physics on D-Branes

MSSM and GUT spectra on D-branes in toroidal orbifold backgrounds provide a class of string vacua, where geometric properties and their effects on physical couplings can be studied in detail. I will discuss how twisted deformation moduli are stabilised by the mere presence of D-branes, while others appear as flat directions, on which tree-level gauge couplings can depend. Their effects have to be weighted against the one-loop threshold corrections to gauge couplings, whose size in turn depends on Kähler moduli, which under certain conditions can give rise to LARGE volumes.

• 27
Talk 7: Magdalena Larfors

Title: Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

I will describe the infinitesimal moduli space of pairs (Y,V) where Y is a manifold with G2 holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. I will show that the presence of V restricts the geometric deformations of Y to lie in the kernel of a G2 Atiyah map", a concept I will explain. I will comment on the resemblance with the holomorphic Atiyah algebroid that arises in heterotic N=1 compactifications, and connect the story to physics, in particular to heterotic compactifications on (Y,V) when α′=0.

• 28
Talk 8: Erik Plauschinn

Title: Partial SUSY Breaking for Asymmetric Gepner Models and Non-geometric Flux Vacua

Asymmetric Gepner models of type IIB string theory with N=1 space-time supersymmetry are constructed. The combinatorics of the massless sector suggests, that these classical Minkowski vacua provide fully backreacted solutions corresponding to N=1 minima of N=2 gauged supergravity. They include, in particular, Calabi-Yau compactifications with so-called non-geometric fluxes.

• 29
Talk 9: Pietro Longhi

Title: Wall Crossing Invariants from Spectral Networks

New relations between wall crossing invariants, such as the BPS monodromy, and various limits of superconformal indices of 4d N=2 theories have been recently proposed. For theories of class S on their Coulomb branches, spectral networks provide a way to compute BPS monodromies directly, in a neighborhood of the superconformal point. Several new results on BPS monodromies can be obtained in this way, bringing new insights into these correspondences.

• Question time
• 12:45 PM
Lunch
• 30
WG2 Discussion - Chair Michela Petrini
• 3:00 PM
Coffee break
• 31
Gongshow
• Poster Session
• 32
WG5 OVERVIEW - Marian Lledò
• WG5 ACTIVITY: Surprise
• WG5 ACTIVITY: Open Discussion
• 33
Social Dinner
• Friday, February 24
• 34
PLENARY TALK 6: Gianguido Dall'Agata

Title: Non-linear realizations of local supersymmetry

I will review recent developments on the construction of supergravity theories where supersymmetry is non-linearly realized and their use in inflationary cosmology.

• 10:20 AM
Coffee break
• 35
INVITED TALK 8: Geoffrey Compère

Title: The E7 black hole entropy

I will first review the construction of the most general non-extremal single center black hole of N=8 supergravity. Its seed is a black hole with 5 independent electromagnetic charges. The appropriate setting to describe the seed solution is the STU model with SO(4,4) hidden symmetries. Some properties of the black hole will be described such as the existence of two regular extremal limits, the presence of a conformal Killing tensor and a mysterious entropy product formula. I will then describe the construction of an E7 invariant which allows to express the black hole entropy.

• 36
Talk 10: Alessandra Gnecchi

Title: BPS black holes in gauged Supergravity: electric-magnetic duality and thermodynamic properties

After reviewing the properties of BPS black holes in Supergravity I will discuss how the requirement of Anti de Sitter asymptotics modify the supersymmetric flow, in relation to their electric and magnetic charges. I will then describe the holographic renormalization needed to construct physical quantities for black holes in AdS at generic temperature in presence of scalar and vector fields, and thus conclude with the discussion of their thermodynamics.

• 37
Talk 11: David Turton

Title: Smooth horizonless geometries deep inside the black-hole regime

The study of black hole microstates in string theory is an important problem, which offers the potential to resolve the information paradox. I will present the first family of horizonless supergravity solutions that have the same mass, charges and angular momenta as general supersymmetric rotating D1-D5-P black holes in five dimensions. This family includes solutions with arbitrarily small angular momenta, deep within the regime of quantum numbers and couplings for which a large classical black hole exists. These geometries are well-approximated by the black hole solution, and in particular exhibit the same near-horizon throat. I will also discuss the physics of an observer falling into a black hole.

• 38
Talk 12: Chiara Toldo

Title: Black holes with halos

I will discuss the features of a class of newly discovered AdS4 black hole solutions solutions arising from M-theory on 7d Sasaki-Einstein coset manifolds. Such thermal black holes are characterized in particular by charged scalars and a massive vector field halo. The analysis of the stability of probes in such a background gives insight on the possible existence of stable of multi-center black holes in anti-de Sitter, relevant for the holographic description of the glass phase transition. (suitable either for gong show or talk)

• Question time
• 12:45 PM
Lunch
• 39
PLENARY TALK 7: Sameer Murthy

Title: Quantum black holes: from macroscopics to microscopics in string theory.

• 40
PLENARY TALK 8: Jan Louis

Title: Supersymmetric AdS backgrounds and their moduli spaces

• 41
COST Closure