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Tim Adamo is a proleptic Lecturer in the School of Mathematics at the University of Edinburgh. He received his BSc from the University of Pittsburgh in 2009 and his PhD from the University of Oxford in 2013. Following junior research fellowships at the University of Cambridge and Imperial College London, he moved to Edinburgh as a Royal Society University Research Fellow in 2019. His work deals with finding geometric formulations of classical and quantum field theories and their observables, using tools from twistor theory and string theory.

With his collaborators, he has developed worldsheet descriptions of gauge theory and gravity, shed light on the connection between chiral symmetry algebras and integrable systems, applied twistor methods to higher-spin theories, and pioneered new approaches to scattering amplitudes in strong background fields.

Kevin Costello holds the Krembil Foundation Hamilton Chair in Mathematical Physics at the Perimeter Institute. He is a mathematical physicist who has worked on a range of topics in topological field theory, quantum field theory, and string theory. In recent years, he developed twisted holography, which is a mathematically well-defined version of the AdS/CFT correspondence; and 4d Chern-Simons theory, which provides a unified theory for two-dimensional integrable systems. His current research focuses on applications of twisted holography to the study of four-dimensional self-dual systems.

Kevin Costello obtained his PhD from Cambridge University under the supervision of Ian Grojnowski in 2003. After postdoctoral appointments at Imperial College London and the University of Chicago, he was a professor at Northwestern University before joining the Perimeter Institute. He is a fellow of the Royal Society, an honorary member of the Royal Irish Academy, and has been awarded the Eisenbud Prize of the American Mathematical Society and the Synge Prize of the Royal Society of Canada.

Laurent Freidel is current faculty Chair at Perimeter Institute. He is a uniquely broad and creative mathematical physicist and a recognized leader in the field of quantum gravity. He has pioneered many influential concepts in quantum gravity such as the notion of relative locality, and developed the theory of spin foam models and group field theory models. Recently he introduced the concept of local holography and corner symmetry that unify non-perturbative quantum gravity with celestial holography. He also provided a direct link between asymptotic gravitational dynamics and the presence of asymptotic *w*-infinity symmetries.

Natalie Paquette is an Assistant Professor of Physics at the University of Washington, Seattle. She has broad interests in string theory, quantum field theory, and mathematical physics, and is particularly interested in work at the intersection of fundamental physics and modern mathematics. Her recent areas of focus include holographic correspondences in asymptotically AdS and flat spacetimes, and their connections to a mathematical notion from homological algebra called Koszul duality, leveraging “twists” of supersymmetric string theoretic dualities (dubbed twisted holography). Paquette obtained her BSc from Cornell University and her PhD from Stanford University. She joined the faculty at the University of Washington after postdoctoral appointments at Caltech as a Burke Institute Fellow, and at the Institute for Advanced Study in Princeton. She is currently a DOE Early Career Research Fellow and a Visiting Fellow at the Perimeter Institute.

Andrea Puhm is an Associate Professor at the University of Amsterdam. Her interests include quantum gravity, string theory and black holes. She received her PhD from the Université Pierre et Marie Curie and IPhT-CEA/Saclay, after which she held postdoctoral positions at UC Santa Barbara and at Harvard University as a Black Hole Initiative Fellow. Prior to joining the University of Amsterdam, she held a tenured research position at the CNRS at Ecole Polytechnique in France. Her research centers around aspects of quantum gravity related to the dynamics and microscopic structure of black hole horizons and the holographic encoding of information in our universe. Her current focus is on formulating a holographic principle for asymptotically flat spacetimes in the form of celestial holography, where she has done influential work on the connection between asymptotic symmetries, conformally soft theorems, and conserved operators in celestial CFT. She is a 2019 laureate of the ERC Starting grant and a Visiting Fellow at the Perimeter Institute.

Tomasz Robert Taylor is a Professor at Northeastern University in Boston and a Visiting Professor at the University of Warsaw in Warsaw, Poland.

He obtained his PhD degree from the University of Warsaw in 1981. He is known for his discovery, with Stephen Parke, of Parke–Taylor amplitudes, also known as maximally helicity violating (MHV) amplitudes; his pioneering use of supersymmetry for computing scattering amplitudes in quantum chromodynamics; his seminal work on topological string amplitudes; his formulation of the first four-dimensional quantum field theory with partial supersymmetry breaking; his extensive studies of superstring scattering amplitudes.

His ongoing work on celestial holography aims to understand the dynamics of gauge theories using holographic methods at both perturbative and non-perturbative levels

Nima Arkani-Hamed is a theorist with wide interests in all aspects of fundamental physics, from quantum field theory and string theory to cosmology and collider physics. His contributions include the paradigm of large extra dimensions, dimensional deconstruction and little Higgs theories, ghost condensation, split supersymmetry, a new framework for dark matter, cosmological collider physics, and the cosmological bootstrap. A motif of his work since the mid-2000’s has been the discovery of deep connections between positivity and fundamental physics, beginning with the derivation of universal positivity constraints on effective field theories, and the “weak gravity conjecture” in quantum gravity.

Over the past decade, he has found a more primary role for positivity in the “amplituhedron program” for at-space holography, discovering scattering amplitudes in a wide range of theories as being determined by new mathematical structures in kinematic space, connecting total positivity, combinatorics, algebra and twistor geometry. His recent work has led to a deeper understanding of the UV/IR connection in celestial holography.

Jordan Cotler is a Junior Fellow at the Harvard Society of Fellows, specializing in quantum gravity, quantum information, and their interconnections. He has developed non-perturbative methods to study the microstructure of black holes, as well as non-perturbative mechanisms for the emergence of time in de Sitter cosmologies. He has invented numerous quantum machine learning algorithms for learning properties of natural systems, some of which have been implemented on Google’s quantum computer. His current interests include bridging methods in quantum gravity and quantum information to advance de Sitter and celestial holography.

Lionel Mason has led many key developments and applications of twistor theory. In mathematics these include constructions of conformally invariant operators, the development of Zoll and Zollfrei manifolds and the classifications of integrable systems. In physics, he introduced twistor actions, applying them to the formulation and proof of the supersymmetric amplitude/Wilson-loop correspondence. He also developed the momentum-twistor Grassmannian and the ambitwistor strings and elucidated their fundamental role in celestial holography.

Sabrina Gonzalez Pasterski (PhD Harvard University, 2019) is a high energy theorist who joined the Perimeter Institute faculty in 2021 after completing a Postdoctoral Fellowship at the Princeton Center for Theoretical Science. She is a young leader in recent efforts to understand the holographic nature of asymptotically flat spacetimes. She has seminal contributions elucidating the imprint of asymptotic symmetries in the dual celestial formulation of gravity, discovering infinite dimensional symmetry enhancements of the S-matrix, a new observable memory effect in gravity, a framework for generalizing these IR features to other theories, and a systematic method to recast S-matrix elements as co-dimension 2 CFT correlators. As the founder and principal investigator of Perimeter’s Celestial Holography Initiative, she is leading a team of amplitudes, mathematical physics, and quantum gravity researchers to jointly tackle this problem of encoding our universe as a hologram. She is excited to serve as one of the deputy directors of the Simons Collaboration on Celestial Holography.

David Skinner is well known for his work on twistors in quantum field theory. He discovered the twistor string for Einstein gravity and provided a new, explicit formulation of the classical gravitational S-matrix. He proved that the *S*-matrix of planar *N* = 4 SYM is dual to a holomorphic Wilson loop in twistor space and developed the twistor description of quantum self-dual Einstein gravity.

Andrew Strominger serves as the Collaboration Director. His interests include quantum gravity, string theory, general relativity, and black holes. In string theory, his contributions include the discovery of Calabi-Yau compactifications, flux compactifications, p-branes, and the microscopic computation of the Bekenstein-Hawking black hole entropy through the construction of a holographically dual 2D CFT. In black hole physics, he solved the CGHS model for 2D black hole evaporation and proposed the measurement of photon ring critical exponents via a space-based extension of the Event Horizon Telescope. In mathematics, he discovered the Strominger system of PDEs for non-Kahler geometry and formulated the SYZ conjecture for mirror symmetry and the OSV conjecture relating Donaldson-Thomas and Gromov-Witten invariants. In bottom-up holography, he proposed the dS/CFT correspondence and the Kerr/CFT correspondence. He defined and demonstrated the BMS invariance of gravitational scattering and its equivalence to the soft graviton theorem and the gravitational memory effect. These have led to a renewed understanding of asymptotic symmetries of gravity along with QED and Yang-Mills theory, as well as observational predictions for new memory effects. Recently he showed that *w*-infinity is an asymptotic symmetry of nature and proposed celestial holography.

Adam Ball is a postdoctoral fellow at Perimeter Institute’s Celestial Holography Initiative. He received his PhD from Harvard in 2022. His research aims to understand the physics at boundaries of various kinds. This includes the celestial hologram at the asymptotic boundary of flat space, the dynamics of edge modes in gauge theory, and the thermodynamics of horizons. Within celestial holography, he has done innovative work characterizing the obstructions to the existence of celestial soft current algebras.

Sangmin Choi is currently a postdoctoral researcher at the University of Amsterdam. He received his PhD in theoretical physics at the University of Michigan in 2021. His research interest spans topics related to the asymptotic symmetries of gauge and gravitational theories and the infrared structure of quantum field theories. This includes BMS symmetries and large gauge transformations, their relation to soft theorems and dressed scattering states, celestial holography, memory effect, JT gravity and Schwarzian mechanics.

He is funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 852386).

Daniel Kapec is a postdoctoral scholar at the Harvard Center of Mathematical Sciences and Applications. He received his PhD in theoretical physics from Harvard University in 2018 and was a postdoctoral scholar at the Institute for Advanced Study from 2018-2021. His interests span a broad range of topics in quantum field theory, general relativity, string theory and quantum gravity. His recent work focuses on classical and quantum mechanical aspects of black hole physics as well as quantum gravity and holography in asymptotically flat spacetimes. He played an instrumental role in establishing the surprising relations between soft theorems for scattering amplitudes, infinite-dimensional asymptotic symmetry groups, and physically measurable memory effects, and more recently has elucidated many of the universal aspects of Celestial Holography

Sruthi Narayanan is currently a postdoctoral fellow at the Perimeter Institute for Theoretical Physics. She received her PhD from Harvard in May 2023. Most of her work thus far has been focused in the area of celestial holography. In particular, she has worked on aspects of the bulk to boundary mapping as well as possible ways to interpret the holographic symmetry algebras present on the celestial sphere. She is interested in extending what we have learned about celestial conformal field theories to certain aspects of non-Abelian gauge theories (i.e. QCD) in an effort to make connections to closely related fields of research like the physics of conformal colliders. Beyond this, she would like to explore ways to understand critical phenomena of the bulk theory from a boundary perspective.

Atul Sharma is a postdoctoral fellow at the Black Hole Initiative, Harvard. He received his PhD in Mathematics from the University of Oxford in 2022. His research interests include scattering amplitudes, twistor theory and twisted holography. Using these tools, he has made key contributions to both bottom-up and top-down constructions in celestial holography. The most striking highlight of his work has been the discovery of Burns holography, the first-ever example of a top-down celestial hologram where the celestial CFT is explicitly obtained.

Bin Zhu is a postdoctoral research associate in the School of Mathematics and Maxwell Institute at the University of Edinburgh. He received his PhD in physics from Northeastern University in 2022. During his PhD, he worked on several topics in celestial CFT. His current research focuses on celestial holography in more general non-trivial backgrounds and the relation between Yang-Mill amplitudes and Liouville CFT correlators. He is also interested in exploring the interplay between scattering amplitudes and twistor theory.

Eduardo Casali has been a postdoctoral researcher at Harvard University since 2021. He received his PhD from the University of Cambridge in 2015, was a postdoctoral researcher at the Mathematical Institute in Oxford University between 2015-2018, and at QMAP in UC Davis from 2018-2021. His work focuses on understanding novel structures in quantum field theory and quantum gravity using tools from twistors and string theory.

He has done pioneering work on ambitwistor strings and their relation to conventional and null strings, as well as on scattering on curved backgrounds. He has given novel worldsheet descriptions of gauge theory and gravity, has found all-loop relations in string theory amplitudes and, more recently, extended well-known structures in conventional amplitudes to celestial correlators.

Luca Ciambelli has been a Postdoctoral Researcher at the Perimeter Institute since 2022. He obtained his PhD from École Polytechnique in 2019, with a thesis focused on the AdS/CFT correspondence, black holes, and their applications. Luca began his postdoctoral career with an appointment at Université Libre de Bruxelles from 2019 to 2022, during which he explored a wide range of topics, including the theory of asymptotic symmetries.

His primary research focus delves into quantum gravity, and the physics of null hypersurfaces, with a particular emphasis on gravity, geometry, and gauge theories. Luca is widely recognized for his expertise in symplectic analysis and the covariant phase space. Notably, he has played a pivotal role in advancing the field of Carrollian holography and has significantly contributed to the development of the “corner proposal” in the realm of quantum gravity.

Prahar Mitra is a postdoctoral scholar at the Institute of Physics at the University of Amsterdam. He received his PhD in theoretical physics from Harvard University in 2017 and was previously a postdoctoral scholar at the School of Natural Sciences at the Institute for Advanced Study (2017-2020) and the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge (2020-2023). His research primarily focuses on classical and quantum aspects of gravity in asymptotically flat and anti-de Sitter spacetimes, though his interests span a wider range of topics in quantum field theory, general relativity, and string theory. He has done pioneering work on the remarkable connection between asymptotic symmetries in asymptotically flat spacetimes and soft theorems in quantum field theory which laid the foundation for the modern development of flat holography. He has also been instrumental in the development of celestial holography in spacetime dimensions greater than four.

Romain Ruzziconi is a Titchmarsh Research Fellow in Mathematical Physics at the University of Oxford. His work focuses on theoretical aspects of classical and quantum gravity, employing methods of asymptotic symmetries, holography, and scattering amplitudes. During his PhD, he worked on the various extensions and avatars of the BMS group in asymptotically flat and (anti-)de Sitter spacetimes and developed covariant phase space methods for systems with leaky boundary conditions. Currently, his work concentrates on flat space holography and exploring the interplay between celestial amplitudes, Carrollian physics, and twistor theory. He is also investigating how symmetries and phase space at null infinity relate with the scattering problem in flat space and loop corrections to soft theorems.

Akshay Yelleshpur is currently a postdoctoral research fellow at the University of Oxford. He received his PhD from Princeton University in 2020 and was a postdoctoral research fellow at Brown University from 2023 – 2023. He is interested in understanding quantum field theory and quantum gravity via their scattering amplitudes. He has worked on various topics including positive geometries in the context of N=4 super Yang-Mills, the mathematics of the singularity structure of scattering amplitudes and Feynman integrals and celestial holography. Within celestial holography, his recent work has focused on exploiting the singularity structure of scattering amplitudes to further our understanding of the 2D dual description.

Erin is a PhD candidate and NSERC scholar at Harvard University. She is broadly interested in celestial holography, scattering amplitudes, and black holes. In her research, she has extended the celestial dictionary to include a correspondence between the Hilbert spaces of the bulk and boundary theories. She has also drawn precise connections between black hole spacetimes and scattering amplitudes, furnishing a realization of bulk self-dual black hole spacetimes in the boundary celestial theory. She is excited about the future prospects of celestial holography to find connections to new subfields and enhance our understanding of the universe.

Iustin is a graduate student at The University of Edinburgh. He is using twistor theory techniques to derive and understand CCFT data at tree-level and beyond, as well as exploring connections between twisted holography and twistors to gain insight into relevant top-down models of celestial holography.

Tianli is a graduate student at Harvard. She is interested in studying flat-space holography via both top-down and bottom-up approaches. From the former aspect, she applied tools recently developed in the context of celestial holography to the BFSS matrix model, an explicit example of flat holography, and clarified its IR structure. From the latter aspect, she is interested in constructing smooth celestial amplitudes by breaking bulk translation invariance, which potentially leads to more realistic CCFT duals. In addition, she is interested in the emergence of bulk Minkowski space from the entanglement between CCFTs.

Walker is an NSF Graduate Research Fellow at Harvard. His work focuses on celestial holography, with a particular focus on understanding the two-dimensional conformal field theory structure of scattering amplitudes in a conformal basis, relating celestial amplitudes to simple structures in the AdS/CFT correspondence, and understanding the importance of 4D translation invariance in constructing realistic celestial duals. Beyond this, he is interested in the construction of explicit 4D/2D holographic dualities and celestial holography as a tool for studying realistic bulk physics.

Yorgo is a graduate student at Ecole Polytechnique in France. He is interested in the symmetries of an asymptotically flat spacetime and their realization on the celestial sphere. Using soft theorems and conformal field theory methods, he has shown that not all BMS symmetries are realized in the celestial CFT which hints towards a necessity for an infinite-dimensional geometry of theories. He is currently working on a well-defined formulation of celestial amplitudes as Mellin transforms of tempered distributions, as well as the implications of the 4D BMS group on the gravitational phase space through the classification of its coadjoint orbits.

Adam is an NSF graduate research fellow at Harvard. Using the connection between soft theorems and asymptotic symmetries, he has demonstrated that the BFSS matrix model enjoys the 11d Lorentz symmetry of flat-space M-theory (indeed, the full asymptotic symmetry group) in its large N limit, supplying a proof for this long-anticipated conjecture. Beyond this, he is interested in non-perturbative aspects of celestial holography: from exact models of CCFT in 0-dimensions to quantities protected by supersymmetry.