Tuesday 23rd May
- Eric Perlmutter - Bootstrapping String Theory
I will review some elements of how CFT correlation functions and symmetries thereof are being more deeply understood, and harnessed to compute string scattering amplitudes, both for holographic CFTs in general and four-dimensional N=4 super Yang-Mills in particular.
https://indico.in2p3.fr/event/28620/attachments/75537/113310/Perlemuter.pdf
- Valentin Reys - Recent advances in precision holography
I will present ongoing efforts to probe the AdS4/CFT3 correspondence beyond the strict large N limit. On the gauge theory side, I will summarize some recent conjectures for the partition functions of 3d SCFTs preserving at least N=2 supersymmetry on various compact Euclidean 3-manifolds. The proposed expressions are perturbatively exact in 1/N, and they are supported by consistency with available analytic results as well as detailed numerical studies. On the gravity side, I will explain how higher-derivative corrections and loop effects account for subleading terms in the large N expansion of boundary observables. Such precision tests of AdS/CFT have important consequences for our understanding of M-theory and quantum aspects of AdS black holes, which I will highlight.
https://indico.in2p3.fr/event/28620/attachments/75537/113313/Reys.pdf
- Alexander Tumanov - Integrability and form factors
Form factors of local operators in N = 4 SYM theory admit a dual description in terms of periodic null-polygonal Wilson loops. Based on this description, we establish an operator product expansion for these objects, which allows us to compute them non-perturbatively in the near-collinear regime. These result exhibit certain unexpected properties, such as the emergence of a non-standard, “tilted”, Bessel kernel. With the use of the perturbative bootstrap approach we promote these the near-collinear results to general kinematics for up to five loop orders in the perturbative expansion.
- Gong-Show
Sangmin Choi - Singular supertranslations and Chern-Simons theory on the black hole horizon
Gabriele Di Ubaldo - 3D Gravity Revitalized
Bastien Duboeuf - Kaluza-Klein spectrometry on the squashed S^7
Felipe Figueroa - Towards new tree-level S-matrices
Baptiste Filoche - Little String Instanton Partition Functions and Scalar Propagators
Bernardo Fraiman - Cosmological Constant Extrema in the O(16)xO(16) Heterotic String
Victor Godet - The Hilbert space of de Sitter quantum gravity
Anthony Guillen - Moduli stabilisation and de Sitter vacuum (?)
Ludwig Horer - Negative scalar potentials and the swampland
Nat Levine - Bootstrapping bulk locality
Hynek Paul - Exact Large Charge in N=4 SYM and Semiclassical String Theory
Yann Proto - Heterotic flux backgrounds and (0,2) linear models
Yilu Shao - Orthosymplectic superinstanton counting
Yihong Wang - Scattering Amplitudes as Bilinear Forms
Vaios Ziogas - U(1) quasi-hydrodynamics: Schwinger-Keldysh effective field theory and holography
https://indico.in2p3.fr/event/28620/attachments/75537/113312/gongshow-FSM-2023.pdf
Wednesday 24th May
- Severin Lüst - Realistic vacua in the String Theory Landscape
This review talk aims to outline the progress and challenges in obtaining realistic vacua within string theory, specifically focusing on vacua with low or fully broken supersymmetry and/or a positive cosmological constant.
https://indico.in2p3.fr/event/28620/attachments/75537/113387/severinlust.pdf
- George Tringas - On/off scale separation
We discuss three-dimensional N=1 AdS flux vacua obtained from compactifications of massive type IIA on G2 holonomy spaces with O2/O6 planes. Similar AdS flux vacuum solutions with parametric scale separation and moduli stabilization have been studied before, however in this new solution, considering a different flux/brane ansatz we show that configurations that are scale-separated can be within finite distance from non-scale-separated ones, while both remain at large volume and weak coupling. More specifically, the transition from non-scale to scale-separated vacua is achieved with the use of a D4-brane modulus, which allows the F4 flux to jump, and has an effective potential always accessible to the three-dimensional low-energy theory. Finally, we show that our analysis allows us to check the distance conjecture, as we can track explicitly the masses of the KK modes.
https://indico.in2p3.fr/event/28620/attachments/75537/113388/tringas.pdf
- Nafiz Ishtiaque - The 4d Chern-Simons perspective of integrability in gauge theories
4d Chern-Simons (CS) theory is a holomorphic-topological theory in four dimensions where line operators form representations of integrable spin chains. I will give an overview of the project relating these spin chains to various supersymmetric gauge theories. We can construct the 4d CS theory and its line operators using branes in string theory and then map the Bethe eigenstates and various spin chain operators to gauge theory observables. I will also explain how these constructions explain various known links between spin chains and gauge theories such as the Bethe/Gauge correspondence, the relation between Yangian algebras and monopole operators, etc.
https://indico.in2p3.fr/event/28620/attachments/75537/113389/NafizIshtiaque.pdf
- Nejc Ceplak - The Correspondence Between Rotating Black Holes and Fundamental Strings
Black holes have a large entropy and it is natural to ask whether this entropy has a statistical interpretation. A possible microscopic picture is given by the correspondence principle, which links black holes and fundamental objects within string theory. The central idea is that the black hole description is valid at large string coupling, but if this coupling is sufficiently decreased, the black hole gets resolved into highly excited string states. If the entropy is held fixed as the coupling is changed, one obtains a microscopic description of black hole entropy. In this talk I will review the correspondence between static black holes and fundamental strings and then describe novel features that appear once one considers the correspondence between rotating black holes and rotating fundamental strings.
https://indico.in2p3.fr/event/28620/attachments/75537/113406/CeplakAnnecy2023PausesFinal.pdf
- Paul Marconnet - Universal accelerating cosmologies from 10d supergravity
Constructing solutions of string theory or supergravity which exhibit accelerated expansion for the 4d spacetime - such as de Sitter vacua - and are free of the various possible pathologies has proven a notoriously difficult problem over the last decades. In this talk, I will present some recent progress made in that direction: I will discuss several 4d FLRW cosmologies obtained from time-dependent compactifications of Type IIA 10d supergravity on various classes of 6d manifolds. The latter cosmologies are dubbed universal in that they do not depend on the detailed features of the compact manifold. Some of them feature eternal or semi-eternal acceleration, whereas others allow for a parametric control on the number of e-foldings. I will also discuss solutions with an infinite number of alternating periods of accelerated and decelerated expansions, that may also be used to build models of inflation.
https://indico.in2p3.fr/event/28620/attachments/75537/113408/Marconnet.pdf
- Sucheta Majumdar - Residual gauge symmetries in the front form
Of the three forms of relativistic dynamics proposed by Dirac, the front form offers a unique framework for studying symmetries of null hypersurfaces. The goal of this talk is to discuss residual gauge symmetries in electromagnetism and gravity in Dirac's front form. Working in the light-cone gauge, I will demonstrate how the large gauge transformations and BMS supertranslations may be obtained from residual gauge invariance of the Hamiltonian action. The residual gauge symmetries in the front form share some striking similarities with the asymptotic symmetries found in the conventional (3+1) Hamiltonian or instant form approach. I will illustrate how the the zero modes play a crucial role in the front form akin to boundary degrees of freedom in the asymptotic analysis at spatial infinity.
https://indico.in2p3.fr/event/28620/attachments/75537/113407/SuchetaMajumdar.pdf
- Mikel Sanchez-Garitaonandia - Large D holographic collisions
The AdS/CFT duality has proven to be an useful tool in understanding properties of strongly coupled QFTs. However, the computational cost in performing real time evolutions in gravitational theories is generally expensive. In this talk I will use a large D effective theory to drastically simplify the study of collisions of Gaussian mass-density, as a model for holographic heavy ion collisions. I will study several collision scenarios identifying regimes of constant entropy growth and comment on its possible relation to chaos.
https://indico.in2p3.fr/event/28620/attachments/75537/113409/Mikel%20Sanchez.pdf
- Blagoje Oblak - Gyroscopic Memory Effects in Gravity and Electrodynamics
This talk is devoted to the net change of orientation, caused by gravitational or electromagnetic waves, on gyroscopes or magnetic dipoles. In both cases, I show that the detector's precession rate involves (gravito-)magnetic data at null infinity, leading to simple memory formulas for finite bursts of radiation. The result is notably related to dual asymptotic symmetries and involves celestially local generators of electric-magnetic duality. As I explain, the effect is certainly observable in electrodynamics, but may also be accessible in gravitational experiments by using distant pulsars as gyroscopes. Based on arXiv:2112.04535, 2203.16216, 2304.12348 with Ali Seraj.
https://indico.in2p3.fr/event/28620/attachments/75537/113410/Oblak.pdf
Thursday 25th May
- Yifei He - Review on S-matrix bootstrap
The S-matrix framework provides a non-perturbative formulation of massive QFTs through scattering amplitudes which satisfy consistency conditions of symmetries, analyticity, crossing and unitarity. The recently revived S-matrix bootstrap program combines these constraints with convex optimization techniques to explore the space of all consistent QFTs, and identify special extremal theories. I will review aspects of the modern S-matrix bootstrap program.
https://indico.in2p3.fr/event/28620/attachments/75537/113461/YifeiHe.pdf
- Taro Kimura - Branes and vertex operators in eight dimensions
In the context of string theory, vertex operators play a role of the creation/annihilation operator of the string states. In this talk, I’ll present a simple vertex operator formalism that describes creation/annihilation of D0/D4/D8 branes on C^4 and its orbifold. In particular, I’ll show (1) how the geometric (orbifold) data appear in the vertex operators, and (2) how the partition function is concisely obtained as a conformal block of the corresponding vertex operators. This talk is based on https://arxiv.org/abs/2212.03870.
https://indico.in2p3.fr/event/28620/attachments/75537/113458/Kimura.pdf
- Yegor Goncharov - Ambient-space variational calculus for gauge fields on constant-curvature spacetimes
We propose a systematic generating procedure to construct free Lagrangians for massive, massless and partially massless, totally-symmetric tensor fields on AdS_{d+1} spacetime starting from the BRST Lagrangian description of massless fields in the flat ambient space R^{2,d}. A novelty is that the Lagrangian is described by a (d + 1)-form on the ambient space whose pullback to the embedding AdS_{d+1} inside R^{2,d} gives the genuine Lagrangian defined on anti-de Sitter spacetime. Our derivation uses the triplet formulation originating from the first-quantized BRST approach, where the action principle is determined by the BRST operator and the inner product of a first-quantised system. In this way we build, in a manifestly so(2,d)-covariant manner, a unifying action principle for the three types of fields mentioned above. In particular, our derivation justifies the form of some actions proposed earlier for massless fields on AdS. We also give a general setup for ambient Lagrangians in terms of the respective jet-bundles and variational bi-complexes. In particular we introduce a suitable ambient-space Euler-Lagrange differential which allows one to derive the equations of motion ambiently, i.e. without the need to explicitly derive the respective spacetime Lagrangian.
https://indico.in2p3.fr/event/28620/attachments/75537/113457/Goncharov.pdf
- Bruno Le Floch - BPS Dendroscopy on Local P2
The spectrum of BPS states in D=4 supersymmetric field theories famously jumps across codimension-one walls in vector multiplet moduli space. The Split Attractor Flow Conjecture posits that the BPS index Ω_z(γ) for given charge γ and moduli z is a finite sum, over attractor flow trees rooted at z and ending at “attractor points”, of combinations of “attractor indices” Ω_*(γ_i) that count BPS states at these points. When it applies, this conjecture provides a classification (or dendroscopy) of the BPS spectrum into different topologies of nested BPS bound states, each having a simple chamber structure. The conjecture is known to hold for quiver quantum mechanics descriptions valid near orbifold-like points in moduli space. Combining this with large-volume results, we proved the conjecture for the whole moduli space of IIA strings compactified on KP2 (the canonical bundle over the projective plane P2). I will present this proof and the resulting dendroscopy, with numerous figures. This is joint work with Pierrick Bousseau, Pierre Descombes, and Boris Pioline.
https://indico.in2p3.fr/event/28620/attachments/75537/113459/LeFloch.pdf
