About

This workshop will explore recent developments in holographic duality, ranging from the original AdS/CFT correspondence to ongoing efforts in extending holography to flat and de Sitter spacetimes. The event aims to bring together leading experts, early-career researchers, and students to foster discussion and collaboration, with the goal of deepening our understanding of holography across diverse settings. The program will feature a balanced mix of pedagogical review lectures, in-depth technical talks, interactive discussion sessions, and a gong show.

Programme

Tuesday
16th September		 Wednesday
17th September		 Thursday
18th September		 Friday
19th September
9:30 - 9:55 Registration
9:55 - 10:00 Opening
10:00-11:15 Shiraz Minwalla Romain Ruzziconi Kostas Skenderis Dionysios Anninos
11:15-11:45 Break
11:45-12:45 Discussion Jakob Salzer Vasileios Letsios Kamran Salehi Vaziri
12:45-14:30 Lunch End of workshop
Lunch at Küçüksu
14:30-15:30 Olga Papadoulaki
(14:00-15:00) 		Panos Betzios Andrea Campoleoni
15:30-16:30 Discussion
(Riccardo Ciccone)
(15:00-16:00) 		GONG SHOW GONG SHOW
16:30-17:00 Boat Ride Break
17:00-18:00 Discussion
(Lorenzo Iacobacci) 		Umut Gürsoy Memorial


REVIEW TALKS

SPEAKER INSTITUTE TOPIC
Dionysios Anninos King's College London
Theory targets for quantum de Sitter We discuss recent avenues attacking the problem of de Sitter space at the quantum level. We discuss Lorentzian and Euclidean methods, as well as (time permitting) quasi-global and quasi-local.
Shiraz Minwalla Tata Institute
AdS Review Abstract
Romain Ruzziconi Harvard University
Towards a Flat Space Hologram from AdS/CFT I will review the current status of flat space holography, focusing on the relation between Carrollian and celestial amplitudes. I will explain how this framework emerges from AdS/CFT through a correspondence between the flat space limit in the bulk and the Carrollian limit at the boundary. I will argue that this perspective could help us construct flat space holograms.
Kostas Skenderis University of Southampton
From AdS to cosmology and flat space I will review the computation of AdS amplitudes and discuss how to obtain cosmological in-in correlators by analytic continuation from AdS and how to obtain flat space scattering amplitudes s by taking a suitable limit of AdS amplitudes.


TECHNICAL TALKS

SPEAKER INSTITUTE TOPIC
Panos Betzios Ghent University
Microscopic models of Cosmology: The case of (A)dS2 I will describe some recent progress in developing microscopic models of two-dimensional cosmologies, emphasizing which desired characteristics they should possess. Then I will focus in the two-dimensional gravitational (compact) Sine-Gordon model that contains (A)dS2 as well as more complicated wineglass and oscillatory wormhole saddles. This model admits a putative microscopic normal matrix model description that allows an in principle non-perturbative description of the physics. I will discuss some recent progress towards establishing and developing this duality.
Andrea Campoleoni UMONS
Flat from AdS, for any spin, and in any dimension The spaces of solutions to the equations of motion of generic gauge theories, including gravity and higher-spin theories, look very different depending on whether the background is flat or (A)dS. Even so, we will show how the solutions of the linearized equations of motion for fields of any spin in Minkowski space can be obtained as a limit of the corresponding solutions in AdS in any even space-time dimension. We will also discuss how this flat-space limit reflects itself in the Flato Fronsdal theorem, which is a cornerstone of higher-spin holography in AdS.
Vasileios A. Letsios UMONS
Unitary Rigid Supersymmetry for the Chiral Graviton and Chiral Gravitino in de Sitter Spacetime It is commonly believed that a unitary supersymmetric quantum field theory (QFT) involving graviton and gravitino fields on fixed 4-dimensional de Sitter spacetime (dS4 ) cannot exist due to known challenges associated with supersymmetry (SUSY) on spaces with positive cosmological constant. In this talk, we contradict this expectation by presenting a new unitary supersymmetric QFT on fixed dS4 : the free supersymmetric theory of the chiral graviton and chiral gravitino fields. The theory overcomes the known obstacles to unitary global SUSY on de Sitter because the commutator between two SUSY transformations closes on the conformal algebra so(4,2) rather than the de Sitter algebra so(4,1). Crucially, the so(4,2) symmetry is realised through unconventional conformal-like transformations. Based on joint work with Atsushi Higuchi: https://arxiv.org/abs/2503.04515
Olga Papadoulaki Ecole Polytechnique
An inflationary cosmology from Anti-de-Sitter wormholes There are various proposals as to what initial state can give rise to an inflationary cosmology. The two most popular ones are the no boundary (Hartle-Hawking) and the tunneling (Vilenkin) proposals. Both of them explain only part of the observations and lead to some paradoxes. I will review these proposals and I will propose a novel initial state (wavefunction) of the universe which in the far past has asymptotically AdS boundary conditions. In the semiclassical limit it is a Euclidean wormhole solution that can give rise to an expanding universe upon analytic continuation to Lorentzian signature. This proposal evades some of the issues that plagued the no boundary and the tunneling proposals. Moreover, the asymptotic AdS conditions in the Euclidean past could in principle allow for the description of inflationary cosmologies and their perturbations within the context of holography, leading to microscopic models.
Jakob Salzer ULB and International Solvay Institutes
Quantizing Carrollian Field Theories Carrollian field theories have recently emerged as a candidate dual to flat space quantum gravity. In this talk, I will discuss the quantization of generic two-derivative electric and magnetic Carrollian theories, highlighting some of the subtleties involved in this process.
As another concrete application, I will discuss the quantization of a two-dimensional BMS3-invariant field theory, which captures the boundary degrees of freedom of three-dimensional flat space gravity.
I will conclude with potential lessons for the program of flat space holography from the carrollian point of view.
Kamran Salehi Vaziri University of Amsterdam
Non-perturbative construction of the de Sitter boundary In this talk, I will review some of the recent progress in non-perturbative quantum field theory in de Sitter such as Kallen-Lehmann and partial wave expansion. I will start by explaining why we are interested in de Sitter and pointing out some of the differences and similarities between anti-de Sitter and de Sitter spacetimes. With the goal of bootstrapping de Sitter's conformal boundary, I will propose a de Sitter-specific bulk-to-boundary expansion, with a continuous family of boundary operators. In the end, I will derive an inversion formula for the bulk-to-boundary expansion, where, given a bulk theory, the boundary operator content is constructed as an integral of the bulk operator times the bulk-to-boundary propagator. These boundary operators exhibit two-point functions that include contact terms alongside standard CFT two-point functions.




DISCUSSION SESSIONS

CONVENER INSTITUTE TOPIC
Lorenzo Iacobacci The Galileo Galilei Institute For Theoretical Physics
Celestial holography from EAdS space We analyse the framework of Celestial holography through the lens of group theory, developing a systematic approach based on Euclidean AdS correlators as fundamental building blocks. These correlators are intrinsically tied to a non-flat foliation of Minkowski spacetime—referred to as the hyperbolic foliation—in which the spacetime is foliated into Euclidean AdS (EAdS) slices inside the light cone and dS slices outside. Employing this foliation, we demonstrate that each contribution to massive Celestial correlators can be reformulated as a linear combination of contributions to corresponding massive Witten correlators in EAdS. We explicitly establish this result for both contact diagrams and the four-point exchange diagram in Celestial holography, and it potentially extends to all orders in perturbation theory by leveraging the bootstrapping properties of the Celestial CFT.
Riccardo Ciccone University of Haifa
QFT in AdS Putting strongly coupled Quantum Field Theories on a rigid Anti-de Sitter background can provide considerable advantages with respect to flat space, a feature first realized by Callan and Wilczek (1989). Such background cures infrared divergences in a way that does not forbid spontaneous symmetry breaking or phase transitions. Moreover, it contains as a natural subsector asymptotic observables which behave like correlators in a conformal theory. The latter feature provides powerful tools to analyze such theories. In this discussion session, I will review this construction and apply it to the foremost example of strongly coupled theories, that is Yang-Mills theories in four spacetime dimensions, both without and with matter. Such approach allows to study the problem of confinement in a more controlled scenario, phrasing it as statement about the (non) existence of certain boundary conditions in the flat space limit. We will also discuss the implications for the endpoint of the conformal window in the presence of matter.




GONG SHOW

SPEAKER INSTITUTE TOPIC
Silvia Georgescu King's College London
Non-linear asymptotic symmetries in warped AdS3 holography Abstract
Samuel Paul Brian King's College London
Features of the Partition Function of a Λ > 0 Universe Abstract
Arvind Shekar University of Southampton
Momentum space Carrollian correlators and Carrollian dual to massive flat scattering Abstract
Radu Moga University of Southampton
Spin-1 Fields in AdS Abstract
Safae Tariq Mohammed V University
Reconstruction of Bulk Operators via Petz Map Abstract
Altay Etkin University of Southampton
Unimodular Jackiw-Teitelboim gravity and de Sitter quantum cosmology Abstract
Stavros Christodoulou University of Cyprus
Subleading soft dressings of asymptotic states in explicit QED processes Abstract



PARTICIPANTS (In person)

NAME INSTITUTE
Ravi Singh IIT-ISM Dhanbad
Mohamed amin Rbah University Mohamed v Rabat
Mohamed Ali Seridi Constantine Mentouri University
Silvia Georgescu King's College London
Kamran Salehi Vaziri University of Amsterdam
Loukas Grimanellis Ruđer Bošković Institute
Emine Seyma Kutluk Scuola Normale Superiore
Lorenzo Iacobacci The Galileo Galilei Institute For Theoretical Physics
Panos Betzios Ghent University
Romain Ruzziconi University of Oxford
Tomáš Procházka CEICO - FZÚ
Joris Raeymaekers CEICO - FZÚ
Rajat Raj TIFR
Umut Can Akça Bogazici University
Mustafa Mullahasanoglu Bogazici University
Samuel Paul Brian King's College London
Arvind Shekar University of Southampton
Akash Singh IISER Mohali
Radu Moga University of Southampton
Roza Mercan Eskin Istanbul Technical University
İsmail Deniz Gün Boğaziçi University
Dharil Shah Ludwig Maximilian University of Munich
Safae Tariq Mohammed V University
Altay Etkin University of Southampton
Eren Akdeniz odtü
Başar Deniz Sevinç Bologna University
Weam Abou Hamdan King's College London
Mohammed Charkaoui Faculty of Sciences, Mohammed V university, Rabat
Ashik H ICTS-TIFR
Sylvain Thomée University of Mons
Saikat Ghosh International Center for Theoretical Sciences Bengaluru
Çağdaş Ulus Ağca Middle East Technical University
Fabrizio Aramini SISSA
Vatsal - University of Cambridge
Pietro Moroni SISSA (Scuola Internazionale Superiore di Studi Avanzati)
Arpan Kundu The Institute of Mathematical Sciences
Elif Büşra Güraksın Boğaziçi Üniversitesi
Andrea De Marco FZU - Prague
Paolo Rossi CEICO
Manizheh Botshekananfard Boğaziçi University
Marzieh Shekari Tousi University of Tehran
Narmin Nasibova Physics Institute of Ministry of Science and Education of Azerbaijan
Pushkar Soni Indian Institute of technology Kanpur
Meysam Hassandoust Sharif University of Technology
Arundhati Goldar Indian Institute of Technology Mandi, India
Sami Mezal Almohammad University of Thi-Qar
Deep Mazumdar Indian Institute of Science Education and Research, Pune
Riccardo Ciccone University of Haifa
Stavros Christodoulou University of Cyprus
Emir Baysazan Istanbul Technical University
Sagnik Misra NISER,Bhubaneshwar
Matheus da Luz Cravo Institute of Theoretical Physics (IFT-UNESP)
Rohit Bhattarai Tribhuvan University, Nepal

REGISTRATION

Registration is now closed.

Only in person participation is possible.



Venue and Accommodation

    The workshop will take place at the Feza Gürsey Center for Mathematics and Physics, Boğaziçi University, Kandilli Campus, İstanbul, Türkiye.

    How to Reach the Conference Venue from Aşiyan via Küçüksu

  • Take the ring boat from Aşiyan → Küçüksu (second stop, ride time: ~15 minutes). This boat follows the Anadolu Hisarı – Küçüksu – Aşiyan line. The official webpage for the boat lines is here.
  • At Küçüksu Pier, go to the Küçüksu bus stop across the road. The link for the timetable for the bus can be found here.
  • Ride for 8 stops and get off at Yalnız Selvi Caddesi
  • After getting off, walk back in the direction the bus came from for about 2 minutes.
  • You’ll see the entrance to Boğaziçi University Kandilli Campus on your left.
  • The main lecture hall is located inside the glass-walled building that will appear right in front you once you enter the campus.

    • How to Reach the Conference Venue from Kadıköy

  • Go to Kadiköy Rıhtım bus stop (this is where you will find many bus stops)
  • Take Bus 14R Küçüksu Kasrı (direction: Kadıköy → Rasathane) from here . The link for the timetable for the bus can be found here.
  • Ride for 38 stops and get off at Yalnız Selvi Caddesi (do not get off at stop called Boğaziçi Üniversitesi Anadolu Hisarı Kampüsü)
  • After getting off, walk in the same direction the bus came from for about 3 minutes
  • You’ll see the entrance to Boğaziçi University Kandilli Campus on your left

    • How to Reach the Conference Venue from Üsküdar

  • Go to Üsküdar Sahil bus stop (this is where you will find many bus stops)
  • Take Bus 15R Rasathane Ortaokulu (direction: Kadıköy → Rasathane) from Üsküdar Camii Önü . The link for the timetable for the bus can be found here.
  • Ride for 25 stops and get off at Yalnız Selvi Caddesi.
  • After getting off, walk in the same direction the bus came from for about 3 minutes
  • You’ll see the entrance to Boğaziçi University Kandilli Campus on your left

ORGANISING COMMITTEE

LOCAL ORGANISING COMMITTEE

  • Ergin Çenebaşı
  • Roza Mercan Eskin
  • Mustafa Mollahasanoğlu
  • Paolo Rossi

SPONSOR

  • TÜBİTAK BİDEB 2232-B 121C138