BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Amihay Hanany (Imperial College London) DTSTART:20200514T090000Z DTEND:20200514T100000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/1 DESCRIPTION:Title: Higgs mechanism\, Hasse diagrams\, and Quiver subtractions\nby Amiha y Hanany (Imperial College London) as part of Rencontres Théoriciennes\n\ nLecture held in Zoom.\n\nAbstract\nThe Hasse diagram is a new way of thin king about moduli spaces of vacua which are hyperKahler cones (otherwise k nown as symplectic singularities) It incorporates the well established the ory behind the Higgs mechanism\, as put forward by Kibble 1967\, with geom etric notions from mathematics\, and modern notions from quiver gauge theo ries.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Tom Hartman (Resultados de la búsqueda Resultados web Cornell Un iversity) DTSTART:20200528T140000Z DTEND:20200528T150000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/2 DESCRIPTION:Title: Replica wormholes and the black hole information paradox\nby Tom Har tman (Resultados de la búsqueda Resultados web Cornell University) as pa rt of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincar é\, Room 314 unless specified otherwise.\n\nAbstract\nI will review recen t progress on the black hole information puzzle involving the appearance o f "islands" in the black hole interior. The islands arise from the replica trick used to calculate the entropy of Hawking radiation. This entropy re ceives large non-perturbative corrections from gravitational instantons ca lled replica wormholes\, which connect multiple copies of the black hole t hrough the interiors. In several toy models where these contributions can be calculated explicitly\, the resulting entropy is consistent with unitar y black hole evaporation.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Costas Bachas (École Normale Supérieure) DTSTART:20200625T090000Z DTEND:20200625T100000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/3 DESCRIPTION:Title: Coupling Holographic Universes\nby Costas Bachas (École Normale Sup érieure) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nHolog raphic duality describes coupled AdS Universes by the weak and/or local ized coupling of CFTs.\nAfter a brief introduction\, I will discuss two re cent results in this context:\n(1) the top down embedding of massive gr avity in string theory\, and (2) the transfer of energy across a conforma l interface.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Stephan Stieberger (MPP) DTSTART:20200618T090000Z DTEND:20200618T100000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/4 DESCRIPTION:Title: Symmetries of celestial amplitudes\nby Stephan Stieberger (MPP) as p art of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincar é\, Room 314 unless specified otherwise.\n\nAbstract\nAbstract: The celes tial sphere is the target space for the proposal of flat space holography in which four-dimensional physics is encoded in two-dimensional celestial conformal field theory (CCFT).\nAfter giving some motivations we introduce the concepts and properties of physics on the celestial sphere.\nWe shall discuss symmetries and properties of celestial amplitudes. After introduc ing the concept of soft theorems on the celestial sphere we shall give an explicit field realization of the operators generating superrotations and supertranslations. Finally we construct the full extended BMS Algebra of C CFT.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Anatoly Dymarsky (U. Kentucky & Skoltech) DTSTART:20200917T130000Z DTEND:20200917T140000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/5 DESCRIPTION:Title: Quantum codes\, lattices\, and conformal field theories\nby Anatoly Dymarsky (U. Kentucky & Skoltech) as part of Rencontres Théoriciennes\n\n Lecture held in online only.\n\nAbstract\nThere is a deep relation between classical error-correcting\ncodes\, Euclidean lattices\, and chiral 2d CF Ts. We show this relation\nextends to include quantum codes\, Lorentzian l attices\, and non-chiral\nCFTs. The relation to quantum codes provides a s imple way to solve\nmodular bootstrap constraints and identify interesting examples of\nconformal theories. In particular we construct many examples of\nphysically distinct isospectral theories\, examples of "would-be" CFT \npartition function -- non-holomorphic functions satisfying all\nconstrai nts of the modular bootstrap\, yet not associated with any\nknown CFT\, an d find theory with the maximal spectral gap among all\nNarain CFTs with th e central charge c=4. We also discuss averaging\nover the ensemble of all CFTs associated with quantum codes\, and its\npossible holographic interpr etation. The talk is based on\narXiv:2009.01236 and arXiv:2009.01244.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Juan Maldacena (IAS) DTSTART:20200924T130000Z DTEND:20200924T140000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/7 DESCRIPTION:Title: Humanly traversable wormholes\nby Juan Maldacena (IAS) as part of Re ncontres Théoriciennes\n\n\nAbstract\nWe will review the construction of traversable wormhole solutions in four dimensions. The simplest constructi on involves magnetic fields and charged massless fermions. These are ingre dients found in the Standard Model at very short distances\, giving us pos sible microscopic wormholes. One can have larger wormholes\, such as the o nes that would allow a person to travel\, by adding an extra "dark sector" with suitable massless matter. One particular example involves the Randal Sundrum II model.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Roberto Emparan (U. Barcelona) DTSTART:20201008T090000Z DTEND:20201008T100000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/9 DESCRIPTION:Title: Quantum BTZ black hole\nby Roberto Emparan (U. Barcelona) as part of Rencontres Théoriciennes\n\n\nAbstract\nI will begin by reviewing the fr amework of braneworld holography as a means of studying quantum effects on black holes including the gravitational backreaction of strongly-coupled conformal fields. Then I will describe a holographic construction of quant um rotating BTZ black holes (quBTZ) using an exact four-dimensional bulk s olution. Besides yielding the quantum-corrected geometry and the renormali zed stress tensor of quBTZ\, we use it to show that the quantum black hole entropy\, which includes the entanglement of the fields outside the horiz on\, rather non-trivially satisfies the first law of thermodynamics\, whil e the Bekenstein-Hawking-Wald entropy does not.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Céline Zwikel (TU Wien) DTSTART:20201001T090000Z DTEND:20201001T101500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/10 DESCRIPTION:Title: Symmetries at Null Boundaries\nby Céline Zwikel (TU Wien) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nI will present and moti vate a program establishing\, in full generality\, the symmetries and char ge analysis for gravitational theories near a generic null hypersurface wi thout specifying any boundary condition. I will illustrate the first step s of this program on three dimensional Einstein gravity. In this case\, th ere are three charges which are generic functions over the codimension one null surface. The integrability of the charges and the charge algebra dep end on the state-dependence of symmetry generators which is a priori not s pecified. I will establish the existence of infinitely many choices that r ender the surface charges integrable. Then\, I will argue that one expects this result to be valid for d > 3 when there is no Bondi news by developi ng some aspects of the four dimensional case. Finally\, I will put our res ults in the context of earlier constructions of near horizon symmetries.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Ben Craps (Vrije Universiteit Brussel) DTSTART:20201022T090000Z DTEND:20201022T101500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/11 DESCRIPTION:Title: Slow scrambling in extremal BTZ and microstate geometries\nby Ben C raps (Vrije Universiteit Brussel) as part of Rencontres Théoriciennes\n\n \nAbstract\nOut-of-time-order correlators (OTOCs) that capture maximally c haotic properties of a black hole are determined by scattering processes n ear the horizon. This prompts the question to what extent OTOCs display ch aotic behaviour in horizonless microstate geometries. This question is com plicated by the fact that Lyapunov growth of OTOCs requires nonzero temper ature\, whereas constructions of microstate geometries have been mostly re stricted to extremal black holes. \n\n\nWe compute OTOCs for a class of ex tremal black holes\, namely maximally rotating BTZ black holes\, and show that on average they display "slow scrambling"\, characterized by cubic (r ather than exponential) growth. Superposed on this average power-law growt h is a sawtooth pattern\, whose steep parts correspond to brief periods of Lyapunov growth associated to the nonzero temperature of the right-moving degrees of freedom in a dual conformal field theory. \n\n\nNext we study the extent to which these OTOCs are modified in certain "superstrata"\, ho rizonless microstate geometries corresponding to these black holes. Rather than an infinite throat ending on a horizon\, these geometries have a ver y deep but finite throat ending in a cap. We find that the superstrata dis play the same slow scrambling as maximally rotating BTZ black holes\, exce pt that for large enough time intervals the growth of the OTOC is cut off by effects related to the cap region\, some of which we evaluate explicitl y.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Andreas Braun (Durham University) DTSTART:20201105T100000Z DTEND:20201105T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/12 DESCRIPTION:Title: Adiabatic Fibrations\, String Dualities and Exceptional Holonomy\nb y Andreas Braun (Durham University) as part of Rencontres Théoriciennes\n \nLecture held in Institut Henri Poincaré\, Room 314 unless specified oth erwise.\n\nAbstract\nNew instances of dualities between string compactific ations can often be understood as a fibre-wise application of known dualit ies. After a review of classic results\, I will give an overview of new in stances of such dualities in the context of manifolds of exceptional holon omy - G2 and Spin(7) - as well as an introduction to the physics related t o such\ngeometries.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Francesco Benini (SISSA) DTSTART:20201126T100000Z DTEND:20201126T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/13 DESCRIPTION:Title: Superconformal index and gravitational path-integral\nby Francesco Benini (SISSA) as part of Rencontres Théoriciennes\n\nLecture held in Ins titut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\n AdS/CFT provides a consistent non-perturbative definition of quantum gravi ty in asymptotically AdS spacetimes. Black holes should correspond to ense mbles of states in the boundary field theory. By performing a careful anal ysis of the superconformal index of 4d N=4 SU(N) Super-Yang-Mills theory\, with the help of a Bethe Ansatz type formula\, we are able to exactly rep roduce the Bekenstein-Hawking entropy of BPS black holes in AdS5 x S5. The large N limit exhibits many competing contributions\, that we are able to identify with complex saddles of the (putative) gravitational path-integr al. Along the way we propose a necessary condition for complex saddles to contribute\, based on the size of their non-perturbative corrections. Such a prescription exactly matches the field theory analysis.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Pavel Kovtun (University of Victoria) DTSTART:20201029T150000Z DTEND:20201029T160000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/14 DESCRIPTION:by Pavel Kovtun (University of Victoria) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unl ess specified otherwise.\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/RENC-THEO/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Massimo Taronna (Naples university) DTSTART:20201210T140000Z DTEND:20201210T150000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/15 DESCRIPTION:by Massimo Taronna (Naples university) as part of Rencontres T héoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unles s specified otherwise.\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/RENC-THEO/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Nikolay Bobev (KU Leuven) DTSTART:20201112T100000Z DTEND:20201112T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/16 DESCRIPTION:Title: The unreasonable effectiveness of higher-derivative supergravity in AdS 4 holography\nby Nikolay Bobev (KU Leuven) as part of Rencontres Théo riciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless sp ecified otherwise.\n\nAbstract\nI will describe the four-derivative correc tions to four-dimensional N=2 minimal gauged supergravity and show that th ey are controlled by two constants. Interestingly\, the solutions of the e quations of motion in the two-derivative theory are not modified by the hi gher derivative corrections. I will use this to arrive at a general formul a for the regularized on shell action for any asymptotically locally AdS4 solution of the theory and show how the higher-derivative corrections affe ct black hole thermodynamic quantities in a universal way. I will employ t hese results in the context of holography to derive new explicit results f or the subleading corrections in the large N expansion of supersymmetric p artition functions on various compact manifolds for a large class of three -dimensional SCFTs arising from M2- and M5-branes. I will also briefly dis cuss possible extensions and generalizations of these results.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Ulf Danielsson (Uppsala University) DTSTART:20201119T100000Z DTEND:20201119T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/17 DESCRIPTION:Title: A journey out of the swamp riding a dark bubble\nby Ulf Danielsson (Uppsala University) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbst ract\nI will discuss how dark energy can be realized using unstable AdS\, with our universe riding an expanding bubble of true vacuum. I will also d iscuss how matter on the bubble is induced from hanging strings ending on the bubble. The construction provides a new way to understand the cosmolog ical horizon\, and there are also implications for particle physics and bl ack holes.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Rajesh Gopakumar (ICTS Bangalore) DTSTART:20210121T100000Z DTEND:20210121T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/18 DESCRIPTION:Title: From Symmetric Product CFTs to AdS$_3$\nby Rajesh Gopakumar (ICTS B angalore) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nHow e xactly do large N QFTs reassemble themselves into perturbative string theo ries? This talk will focus on an example which explicitly illustrates a ge neral program of how this can happen around a free field fixed point. Spec ifically\, we consider n-point correlators in the symmetric product orbifo ld theory\, dual to tensionless strings on AdS_3\, in a Gross-Mende like l imit of large conformal dimensions. These correlators are given in terms o f branched covering maps which we can exactly solve for in this limit\, vi a a map to a matrix model with a logarithmic potential. The spectral curve encoding the matrix model solution then naturally gives rise to an integr al over the dual string moduli space through a special (Strebel) parameter ization of the latter. This is a precise realisation of what was proposed as the underlying mechanism for gauge-string duality in weakly coupled QFT S. Finally\, the integrand on the moduli space can be cast in a number of striking forms including an action given by (the modulus of) the Schwarzia n of the covering map.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Eric Perlmutter (Caltech & IPhT) DTSTART:20210128T100000Z DTEND:20210128T111500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/19 DESCRIPTION:Title: A CFT Distance Conjecture\nby Eric Perlmutter (Caltech & IPhT) as p art of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincar é\, Room 314 unless specified otherwise.\n\nAbstract\nWe formulate a seri es of conjectures relating the geometry of conformal manifolds to the spec trum of local operators in conformal field theories in d>2 spacetime dimen sions. We focus on conformal manifolds with limiting points at infinite di stance with respect to the Zamolodchikov metric. Our central conjecture is that all theories at infinite distance possess an emergent higher-spin sy mmetry\, generated by an infinite tower of currents whose anomalous dimens ions vanish exponentially in the distance. Stated geometrically\, the diam eter of a non-compact conformal manifold must diverge logarithmically in t he higher-spin gap. Our conjectures are related to the Distance Conjecture in the swampland program. We discuss the supporting evidence\, their holo graphic interpretation\, and implications for superconformal field theorie s.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Justin Kaidi (SCGP Stony Brook) DTSTART:20201203T140000Z DTEND:20201203T151500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/20 DESCRIPTION:Title: Adventures in Non-Supersymmetric String Theory\nby Justin Kaidi (SC GP Stony Brook) as part of Rencontres Théoriciennes\n\n\nAbstract\nIt has long been known that there exist strings with supersymmetry on the world sheet\, but not in spacetime. These include the well-known Type 0 strings\ , as well as a series of seven heterotic strings\, all of which are obtain ed by imposing unconventional GSO projections. Besides these classic examp les though\, relatively little is known about the full space of non-SUSY t heories. One of the reasons why non-SUSY strings have remained understudie d is the fact that nearly all of them have closed string tachyons\, and he nce do not admit ten-dimensional flat space as a stable vacuum. The goal o f this talk is two-fold. First\, using recent advances in condensed matter theory\, we will reinterpret GSO projections in terms of topological phas es of matter\, thereby providing a framework for the classification of non -SUSY strings. Having done so\, we will show that for all non-SUSY theorie s in which a tachyon exists\, it can be condensed to give a stable lower-d imensional vacuum. In many cases\, these stable vacua will be two-dimensio nal string theories already known in the literature.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Gordon Semenoff (UBC) DTSTART:20201217T150000Z DTEND:20201217T161500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/21 DESCRIPTION:Title: Infrared information: an accelerated quark paradigm\nby Gordon Seme noff (UBC) as part of Rencontres Théoriciennes\n\nLecture held in Institu t Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nSome observations about the interplay of quantum information theoretic issues and the infrared problem in gauge field theories are reviewed. A simple m odel of a quantum amplitude computation for accelerated heavy quarks in N= 4 supersymmetric Yang-Mills theory is formulated and used to study the inf rared divergences which would arise at the leading order of weak coupling perturbation theory. It is argued that the answer to some fundamental que stions about the realization of global colour symmetry depend crucially on how the infrared problem is resolved. An extrapolation of some aspects of the discussion to strong coupling and large $N$ using AdS/CFT holography are explored.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Jan de Boer (Amsterdam) DTSTART:20210114T094500Z DTEND:20210114T110000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/22 DESCRIPTION:Title: Spacetime as a quantum circuit\nby Jan de Boer (Amsterdam) as part of Rencontres Théoriciennes\n\nLecture held in Zoom.\n\nAbstract\nI will review some recent work (arXiv:2101.01185) which proposes to identify the on-shell\ngravitational action for regions in spacetime with the complexit y of a suitable quantum circuit\, which significantly extends previous pro posals on path integral optimization and complexity.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Matthijs Hogervorst (EPFL) DTSTART:20210211T100000Z DTEND:20210211T114500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/23 DESCRIPTION:Title: Back to the future with the epsilon expansion\nby Matthijs Hogervor st (EPFL) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nThe e psilon expansion is a well-known framework in quantum field theory to cons truct weakly-coupled fixed points of the RG flow. Nevertheless\, little is known about the landscape of theories it describes\, beyond some well-kno wn CFTs like the Ising and the O(N) models. In this talk we revisit the pr oblem of classifying multiscalar fixed points\, in the process proving new results their spectra. Moreover\, we show that there is no weakly-coupled gauged fixed point with fewer than 183 flavors.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Yu-Tin Huang (National Taiwan University) DTSTART:20210225T090000Z DTEND:20210225T114500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/24 DESCRIPTION:Title: An EFT/CFT ``Duality": from the modular-hedron to the EFT-hedron\ nby Yu-Tin Huang (National Taiwan University) as part of Rencontres Théor iciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless spe cified otherwise.\n\nAbstract\nIn this talk we will show that the space of consistent EFTs and 2D CFTs are governed by the same geometry. For the fo rmer\, the theory space stems from a four-point S-matrix that is consisten t with having a crossing symmetric unitary and Lorentz invariant UV comple tion\, while the latter is deduced from modular invariant torus partition functions. We will show that in both cases\, the space is given by a produ ct geometry of convex hull of points on positive moment curves\, intersec ting with the subplane reflecting crossing/modular symmetry. We will provi de evidence that a particular vertex of the intersecting geometry gives th e extremal spectrum of the discretize (derivative expansion) bootstrap pro blem.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniele Dorigoni (Durham) DTSTART:20210311T100000Z DTEND:20210311T114500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/25 DESCRIPTION:Title: An exact integrated correlator in $N=4$ SU(N) SYM\nby Daniele Dorig oni (Durham) as part of Rencontres Théoriciennes\n\nLecture held in Insti tut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nBe tween all the magical properties of $\\mathcal{N} = 4$ SU(N) super Yang-Mi lls perhaps one of the most important is Montonen-Olive electric-magnetic $SL(2\,Z)$ duality.In particular this leads to the constraint that observa bles must be invariant under inversion of the complex YM coupling $\\tau$\ , i.e. under $\\tau \\to -1 / \\tau$. In this talk we will focus on one su ch physical quantity\, namely an integrated correlator of four super-confo rmal primaries of the stress-tensor multiplet. I will firstly review how t his correlator can be computed via supersymmetric localisation on $S^4$\, and then discuss how this quantity can be rewritten in a manifestly $SL(2\ ,Z)$ invariant way for any number of colours N\, and any value of the comp lex YM coupling \\tau. Thanks to this novel expression we can explore vari ous different regimes: perturbative SYM\, large-N supergravity approximati on\, large-N 't Hooft expansion. All of these regimes are connected via a remarkable Laplace-difference equation relating the SU(N) to the SU(N + 1) and SU(N −\; 1) correlators.\n\nOnline only. Zoom password=1234\n LOCATION:https://researchseminars.org/talk/RENC-THEO/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Guerrieri (Tel-Aviv) DTSTART:20210318T090000Z DTEND:20210318T093000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/26 DESCRIPTION:Title: Where is String Theory?\nby Andrea Guerrieri (Tel-Aviv) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Ro om 314 unless specified otherwise.\n\nAbstract\nIn the recent past the S-m atrix Bootstrap has provided precise quantitative bounds on the low energy Wilson coefficients compatible with causality\, crossing symmetry and uni tarity for some class of EFTs associated with the low energy QCD dynamics. In this talk I will discuss the first application of this formalism to qu antum gravity theories. I will focus on the first non universal correction to the flat space scattering amplitude of 10 dimensional supergravity par ticles\, and compare the results with the String Theory predictions.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Blaise Goutéraux (Ecole Polytechnique) DTSTART:20210325T100000Z DTEND:20210325T114500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/27 DESCRIPTION:Title: Hydrodynamic diffusion and its breakdown near AdS2 fixed points\nby Blaise Goutéraux (Ecole Polytechnique) as part of Rencontres Théoricien nes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specifie d otherwise.\n\nAbstract\nHydrodynamics provides a universal description o f interacting quantum field theories at sufficiently long times and wavele ngths\, but breaks down at scales dependent on microscopic details of the theory. We use gauge-gravity duality to investigate the breakdown of diffu sive hydrodynamics in two low temperature states dual to black holes with AdS$_2$ horizons. We find that the breakdown is characterized by a collisi on between the diffusive pole of the retarded Green's function with a pole associated to the AdS$_2$ region of the geometry\, such that the local eq uilibration time is set by infra-red properties of the theory. The absolut e values of the frequency and wavevector at the collision ($\\omega_{eq}$ and $k_{eq}$) provide a natural characterization of all the low temperatur e diffusivities $D$ of the states via $D=\\omega_{eq}/k_{eq}^2$ where $\\o mega_{eq}=2\\pi\\Delta T$ is set by the temperature $T$ and the scaling di mension $\\Delta$ of an infra-red operator. We confirm that these relation s are also satisfied in an SYK chain model in the limit of strong interact ions.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Rob Myers (Perimeter Institute) DTSTART:20210401T130000Z DTEND:20210401T141500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/28 DESCRIPTION:Title: Quantum Extremal Islands made easy\nby Rob Myers (Perimeter Institu te) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nWe illustra te the appearance of quantum extremal islands in holographic setups in hig her dimensions. We emphasize the close parallel with the behaviour of holo graphic entanglement entropy in more familiar settings.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Aninda Sinha (IISc) DTSTART:20210408T090000Z DTEND:20210408T101500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/29 DESCRIPTION:Title: Crossing symmetric dispersion relations for QFTs\nby Aninda Sinha ( IISc) as part of Rencontres Théoriciennes\n\nLecture held in Institut Hen ri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nI will co nsider fully crossing symmetric dispersion relations for 2-2 scattering of identical massive scalar scattering in QFT reviving certain old ideas in the 1970s. I will show how two sided bounds on Wilson coefficients can be derived using this dispersion relation by establishing the univalence of t he kernel. I will also discuss how a generalized Froissart bound arises fr om the same.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Simeon Hellerman (Tokyo University) DTSTART:20210506T080000Z DTEND:20210506T094500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/30 DESCRIPTION:Title: How Different Is More? : Precision correlators at large R-charge\nb y Simeon Hellerman (Tokyo University) as part of Rencontres Théoriciennes \n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified o therwise.\n\nAbstract\nBuilding up macroscopic physics from microscopic co nstituents is an idea as old as theoretical physics itself\, and has been a perennial theme in quantum theory beginning with Bohr's correspondence p rinciple and onward through the modern renormalization group. Recently th ere has been a semi-organized effort at applying this principle to strongl y coupled conformal field theory\, developing asymptotic series in inverse powers of a large quantum number as a systematic approximation scheme who se leading-order term is the familiar macroscopic limit. I will discuss t his idea in the case of N=2 superconformal gauge theory in four dimensions \, where it is possible to compute the large-quantum-number asymptotic ser ies to all orders and even a hyperasymptotic series for the exponentially small corrections to it that are associated with the leading qualitative b reakdown of the naive macroscopic picture. The results quite easily yield approximations accurate to 4-6 significant digits for quantum numbers of order 1\, to 15 significant digits or better for quantum numbers of order 100. I will discuss the implications for one's general picture of the lar ge-scale structure of theory space.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/30/ END:VEVENT BEGIN:VEVENT SUMMARY:Wolfgang Lerche (CERN) DTSTART:20210603T090000Z DTEND:20210603T103000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/32 DESCRIPTION:Title: Fluxes\, Holomorphic Anomalies and Elliptic Genera in $d=4$\nby Wol fgang Lerche (CERN) as part of Rencontres Théoriciennes\n\nLecture held i n Institut Henri Poincaré\, Room 314 unless specified otherwise.\n\nAbstr act\nMotivated by tests of Weak Gravity Conjectures\, we investigate prope rties of elliptic genera of string theories that arise in large distance l imits of the moduli space of F-theory compactifications. This allows for a non-perturbative definition of elliptic genera that goes beyond the ordin ary world-sheet description. While this construction has been known for si x-dimensional theories\, we find the four-dimensional variant to be surpri singly complex. The essential new ingredient is background fluxes\, and th ese lead to different sectors of the elliptic genus with different modular properties. Crucial is the appearance of derivatives which leads to novel modular (and hence\, holomorphic) anomalies that are worse than naively e xpected. We also give a physical interpretation of these phenomena.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Douglas Stanford (Stanford) DTSTART:20210415T150000Z DTEND:20210415T161500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/33 DESCRIPTION:Title: Wormholes without averaging\nby Douglas Stanford (Stanford) as part of Rencontres Théoriciennes\n\nLecture held in Institut Henri Poincaré\ , Room 314 unless specified otherwise.\n\nAbstract\nSpacetime wormholes ha ve contributed a lot to recent understanding of quantum black hole physics \, but they lead to puzzles. One way to resolve the puzzles is to interpre t the wormholes as computing an average over theories. But what happens if we don't average? Are the wormholes still there? We will discuss this in a very simple model\, a reduction of the SYK quantum mechanics model. Afte r averaging over couplings\, the collective field description contains "wo rmhole" solutions. We show that the wormhole solutions survive intact in t he non-averaged theory\, but there are also new "half wormhole" contributi ons from elsewhere in the integration space.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Marc Gillioz (SISSA) DTSTART:20210422T090000Z DTEND:20210422T101500Z DTSTAMP:20260422T225848Z UID:RENC-THEO/34 DESCRIPTION:Title: A scattering amplitude in conformal field theory\nby Marc Gillioz ( SISSA) as part of Rencontres Théoriciennes\n\nLecture held in Institut He nri Poincaré\, Room 314 unless specified otherwise.\n\nAbstract\nThere ar e no particles in conformal field theory\, but it is still possible to def ine scattering amplitudes using a conformal version of the LSZ reduction f ormalism\, which makes use of branch points instead of poles in correlatio n functions expressed in momentum space. These amplitudes have many famili ar properties\, including crossing symmetry and unitarity cuts. They match ordinary scattering amplitudes in perturbative examples\, but are truly n on-perturbative and can potentially be used as a new approach to bootstrap a theory.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/34/ END:VEVENT BEGIN:VEVENT SUMMARY:Thomas Grimm (Utrecht) DTSTART:20210916T080000Z DTEND:20210916T090000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/35 DESCRIPTION:Title: Asymptotic Flux Compactifications and the Tameness of the Landscape \nby Thomas Grimm (Utrecht) as part of Rencontres Théoriciennes\n\nLectur e held in Institut Henri Poincaré\, Room 314 in hybrid mode.\n\nAbstract\ nIt has only recently become possible to systematically study flux compact ifications in asymptotic regions of the field space without the necessity to construct specific geometric examples. I will explain some key insights about the structure of the complex structure moduli space\, its boundarie s and asymptotic regions\, that opened the door for this general approach. I will then argue that a long conjectured and very non-trivial finiteness result about flux vacua has now been proved. Motivated by these successes \, I will suggest that requiring finiteness properties on the coupling fun ctions of any effective theory could be key to generally uncover the struc ture of the string theory landscape. I will briefly introduce a concrete f ramework\, dealing with o-minimal structures and tame topology\, that auto matically implements finiteness properties.\n\nZoom code: 1234\n LOCATION:https://researchseminars.org/talk/RENC-THEO/35/ END:VEVENT BEGIN:VEVENT SUMMARY:Cyril Closset (Birmingham) DTSTART:20210916T093000Z DTEND:20210916T103000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/36 DESCRIPTION:Title: The Coulomb branch of 5d superconformal field theories on a circle\ nby Cyril Closset (Birmingham) as part of Rencontres Théoriciennes\n\nLec ture held in Institut Henri Poincaré\, Room 314 in hybrid mode.\n\nAbstra ct\nI will revisit the Seiberg-Witten description of the Coulomb branch of rank-one 4d N=2 supersymmetric QFTs\, including aspects of the global sym metry\, from the point of view of rational elliptic surfaces. This will in clude\, in particular\, a detailed study of the 5d superconformal field th eories with E_n symmetry\, compactified on a circle. I will also sketch ho w to derive BPS quivers from that perspective. Interesting modular propert ies of the SW geometries will play a key role.\n\nZoom code: 1234\n LOCATION:https://researchseminars.org/talk/RENC-THEO/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Leron Borsten (Heriot–Watt University\, Edinburgh) DTSTART:20211021T093000Z DTEND:20211021T103000Z DTSTAMP:20260422T225848Z UID:RENC-THEO/37 DESCRIPTION:Title: On colour-kinematic duality and the double copy\nby Leron Borsten ( Heriot–Watt University\, Edinburgh) as part of Rencontres Théoriciennes \n\nLecture held in Institut Henri Poincaré\, Room 314 unless specified o therwise.\n\nAbstract\nWe begin by reviewing the colour-kinematics duality of (super) Yang-Mills theory and its double copy into (super)gravity.\nWe then show that off-shell colour-kinematics duality can be made manifest i n the Yang—Mills Batalin–Vilkovisky action\, up to Jacobian counter-te rms. This\, in turn\, implies the validity of the double copy to all order s in perturbations theory.\nWe then describe the mathematical underpinning s of these observations in terms of Homotopy algebras. Figuratively\, colo ur-kinematics duality is a symmetry of Yang—Mills in the same sense that a mug is a donut.\nWe conclude by discussing generalisations to super Yan g-Mills theory\, where Sen’s formalism for self-dual field strengths eme rges automatically.\n LOCATION:https://researchseminars.org/talk/RENC-THEO/37/ END:VEVENT END:VCALENDAR