BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Kiryl Pakrouski (Princeton University) DTSTART:20200724T174500Z DTEND:20200724T190000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/1 DESCRIPTION:Title: Many body scars as a group invariant sector of Hilbert space\nby Kiryl Pakrouski (Princeton University) as part of IA S High Energy Theory Friday Seminars\n\n\nAbstract\nWe present a class of Hamiltonians H for which a sector of the Hilbert space invariant under a L ie group G\, which is not a symmetry of H\, possesses the essential proper ties of many-body scar states. These include the absence of thermalization and the non-decaying “revivals” of special initial states in time ev olution. Some of the scar states found in earlier work may be viewed as sp ecial cases of our construction. A particular class of examples concerns i nteracting spin-1/2 fermions on a lattice consisting of N sites (Fermi-Hub bard model as a special case)\, and we show that it contains two families of N+1 scar states. One of these families\, which was found in recent lite rature\, is comprised of the well-known eta-pairing states that have been linked to superconductivity. We find another family of scar states which i s U(N) invariant.\n\nBoth families and most of the group-invariant scar st ates produced by our construction in general\, give rise to the off-diagon al long range order which survives at high temperatures and is insensitive to the details of the dynamics. Such states could be used for reliable qu antum information processing because the information is stored non-locally \, and thus cannot be easily erased by local perturbations. This talk will be based on arXiv:2007.00845.\n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Lorenz Eberhardt (Institute for Advanced Study) DTSTART:20200828T174500Z DTEND:20200828T190000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/2 DESCRIPTION:Title: Partition functions of the tensionless string\nby Lorenz Eberhardt (Institute for Advanced Study) as part of IAS High Energy Theory Friday Seminars\n\n\nAbstract\nI discuss string theory on A dS3xS3xT4 in the tensionless limit\, with one unit of NS-NS flux. This the ory is conjectured to be dual to the symmetric product orbifold CFT. I sho w how to compute the full string partition function on various locally AdS 3 backgrounds\, such as thermal AdS3\, the BTZ black and conical defects\, and find that it is independent of the actual background\, but only depen ds on the boundary geometry. Consequently\, reproducing the boundary parti tion function does not require a sum over bulk geometries\, but rather agr ees with the string partition function on any bulk geometry with the appro priate boundary. I argue that the same mechanism shows the factorization o f the bulk partition function when geometries with disconnected boundaries are considered.\n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Aidan Herderschee (Institute for Advanced Study) DTSTART:20230915T150000Z DTEND:20230915T160000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/3 DESCRIPTION:Title: The Next-to-Leading Order Scattering Waveform f rom Amplitudes\nby Aidan Herderschee (Institute for Advanced Study) as part of IAS High Energy Theory Friday Seminars\n\n\nAbstract\nI will show case the computation of the next-to-leading order scattering waveform in c lassical gravity using amplitude techniques. I will first give an overview of how to compute generic classical observables in gravity using scatteri ng amplitude techniques in the KMOC formalism. In particular\, I will focu s on how classical physics systematically emerges from quantum amplitudes and how calculations simplify in the classical limit. I will then sketch t he computation of the sub-leading contribution to the classical waveform\, an out-of-time-order observable which roughly corresponds to the 1-loop 5 -point amplitude. I will conclude with a discussion of different aspects o f the waveform\, such as the memory effect and an IR divergent phase\, alo ng with future directions.\n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Borinsky (ETH Zurich) DTSTART:20231006T150000Z DTEND:20231006T160000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/4 DESCRIPTION:Title: The Dark-Matter Problem of the Moduli Space of Curves and its (partial) Tropical Solution\nby Michael Borinsky (ETH Z urich) as part of IAS High Energy Theory Friday Seminars\n\n\nAbstract\nTh e moduli space of curves\, M_g\, is an object of pivotal interest in mathe matics and theoretical physics. Even though it has been studied with treme ndous effort\, little is known about its topology. For instance\, the tota l dimension of the cohomology of M_g grows quickly with g\, but the known constructions for cohomology classes only account for a negligibly small p art of this growth. The known existence of huge amounts of cohomology and the lack of explanation for it\, is dubbed the 'dark-matter problem' of M_ g. In this talk\, I will review the state-of-the-art and a recent breakthr ough by Chan-Galatius-Payne who used a tropicalization of the moduli space of curves to construct a new source of cohomology in M_g which quickly dr afts all previously known sources. Eventually\, I will present new result s which show that this new source still only accounts for a small part of the total cohomology. The proof makes use of QFT inspired path-integrals. \n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Nikita Sopenko (Institute for Advanced Study) DTSTART:20231020T150000Z DTEND:20231020T160000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/5 DESCRIPTION:Title: Equivariant Higher Berry Classes for Quantum Ma ny-Body Systems\nby Nikita Sopenko (Institute for Advanced Study) as p art of IAS High Energy Theory Friday Seminars\n\n\nAbstract\nI will talk a bout the invariants of topologically ordered states of quantum lattice sys tems that generalize Berry classes and can be defined for any gapped state in any dimension. The equivariant version of such invariants unifies and generalizes the Hall conductance and the Thouless pump. I will also discus s the construction of 2d chiral states for which these invariants can be c omputed exactly providing evidence that these states realize topological o rder associated with an arbitrary unitary rational vertex operator algebra .\n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Qianshu Lu (Institute for Advanced Study) DTSTART:20231208T160000Z DTEND:20231208T170000Z DTSTAMP:20260404T094801Z UID:IAS_HighEnergyTheory_Friday/6 DESCRIPTION:by Qianshu Lu (Institute for Advanced Study) as part of IAS Hi gh Energy Theory Friday Seminars\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IAS_HighEnergyTheory_Fri day/6/ END:VEVENT END:VCALENDAR