BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Alejandro Cabo-Bizet (King's College) DTSTART:20200604T140000Z DTEND:20200604T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/1 DESCRIPTION:Title: On the large N limit of the 4d N=1 superconformal index\nby Alej andro Cabo-Bizet (King's College) as part of HEP seminars TU Wien (Vienna) \n\n\nAbstract\nThe large N limit of the 4d N=1 superconformal index is\na rgued to be determined by competition among complex eigenvalue\nconfigurat ions. At least some of these configurations correspond to\nembeddings of a belian discrete groups of order N upon a 2-torus. Via\nthe principles of A dS/CFT correspondence one of these configurations\nmaps to a regular Wick- rotated section of a supersymmetric rotating and\nelectrically charged Lor entzian AdS5 black hole. After an introduction\nto the problem\, that will include a survey over the analytic frame that\nallows us to quantify the competition among elements of a sub-family of\nthese complex eigenvalue co nfigurations\, I will end with an\ninterpretation of our results for SU(N) N=4 SYM\, and a comparison with\nrecently reported numerical studies.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Miguel Montero (Harvard U.) DTSTART:20200618T140000Z DTEND:20200618T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/2 DESCRIPTION:Title: Nothing is certain in string compactifications\nby Miguel Monter o (Harvard U.) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nA b ubble of nothing is a spacetime instability where a compact dimension coll apses. After nucleation\, it expands at the speed of light\, leaving "noth ing" behind. There are a couple of robust mechanisms that can prevent the existence of a bubble: Either it is not energetically favourable to produ ce them\, or there is a topological obstruction to their existence. The la tter is often the case with SUSY-preserving boundary conditions. I will e xplain how to understand the topological obstruction in detail using bordi sm\, which will show that it is very generically absent even for a SUSY-co mpatible spin structure. As a proof of principle\, we construct and embed in string theory an explicit bubble of nothing for a T3 with completely pe riodic (SUSY-compatible) spin structure. There is a dynamical obstruction due to a positive energy theorem which is circumvented by higher-derivat ive corrections. Our model can be embedded in string theory. Our techniqu es can be used to construct a plethora of bubbles of nothing for spaces of interest like CY6's\, G2 manifolds\, or Sasaki-Einstein manifolds. We wil l explain how to study and circumvent the topological and dynamical obstru ction in these cases. Avoiding the dynamical obstruction means avoiding a modified energy condition which might be related to the Weak Gravity Conje cture. Our results lend support to the conjecture that any \nnon-supersym metric vacuum of quantum gravity is ultimately unstable.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Charles Marteau DTSTART:20200625T140000Z DTEND:20200625T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/3 DESCRIPTION:Title: New boundary conditions for AdS2\nby Charles Marteau as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nWe describe new boundary cond itions for AdS2 in Jackiw-Teitelboim gravity. The asymptotic symmetry grou p is enhanced to Diff(S1)⋉C∞(S1) whose breaking to SL(2\,R)×U(1) cont rols the near-AdS2 dynamics. The action reduces to a boundary term which i s a generalization of the Schwarzian theory. It can be interpreted as the coadjoint action of the warped Virasoro group. We show that this theory is holographically dual to the complex SYK model. We compute the Euclidean p ath integral and derive its relation to the random matrix ensemble of Saad \, Shenker and Stanford. We study the flat space version of this action\, and show that the corresponding path integral also gives an ensemble avera ge\, but of a much simpler nature. We explore some applications to near-ex tremal black holes.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Hiroshi Ooguri (Caltech & Kavli IPMU) DTSTART:20200709T140000Z DTEND:20200709T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/5 DESCRIPTION:Title: Testing Swampland Conjectures\nby Hiroshi Ooguri (Caltech & Kavl i IPMU) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nOver the l ast fourteen years\, a variety of swampland conditions have been proposed with various degrees of rigor. In this talk\, I will discuss tests of some of these conjectures that do not rely on specific string theory construct ions. They include constraints on symmetry\, strength of gravitational cou plings\, cobordism between theories\, and issues with lower dimensional th eories.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Paul Steinhardt (Princeton) DTSTART:20201105T150000Z DTEND:20201105T160000Z DTSTAMP:20260404T095653Z UID:HEPTUW/6 DESCRIPTION:Title: Smoothing and Flattening the Universe\nby Paul Steinhardt (Princ eton) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nThe most sal ient feature of the observable universe is that it is homogeneous and spat ially flat on large scales. This talk will argue why this may only be expl ained by replacing the big bang with a big bounce preceded by a period of slow contraction\, a conclusion which has profound implications for cosmol ogy and fundamental physics.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Kévin Nguyen (King's College) DTSTART:20201008T140000Z DTEND:20201008T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/7 DESCRIPTION:Title: The effective action of superrotation modes\nby Kévin Nguyen (K ing's College) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nSta rting from an analysis of four-dimensional asymptotically flat gravity in first order formulation\, we show that superrotation reparametrization mod es are governed by an Alekseev--Shatashvili action on the celestial sphere . This two-dimensional conformal theory describes spontaneous symmetry bre aking of Virasoro superrotations together with the explicit symmetry break ing of more general Diff(S2) superrotations. We arrive at this result by f irst reformulating the asymptotic field equations and symmetries of the ra diative vacuum sector in terms of a Chern--Simons theory at null infinity\ , and subsequently performing a Hamiltonian reduction of this theory onto the celestial sphere.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Arthur Hebecker (U. Heidelberg\, ITP) DTSTART:20201015T130000Z DTEND:20201015T140000Z DTSTAMP:20260404T095653Z UID:HEPTUW/8 DESCRIPTION:Title: De Sitter from String Theory: Control Issues of KKLT\nby Arthur Hebecker (U. Heidelberg\, ITP) as part of HEP seminars TU Wien (Vienna)\n\ n\nAbstract\nAfter a brief introduction to the problem of realising de Sit ter space in string compactifications\, I will describe the specific propo sal of Kachru\, Kallosh\, Linde and Trivedi (KKLT)\, including some of its criticism. I will then explain why\, according our recent analysis\, exte nded singularities in the bulk of the compact space appear to generically threaten the construction. Possible escape routes from this "bulk singular ity problem" will also be discussed.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Shubham Maheshwari (Groningen) DTSTART:20201022T140000Z DTEND:20201022T150000Z DTSTAMP:20260404T095653Z UID:HEPTUW/9 DESCRIPTION:Title: Stable\, ghost-free solutions in UV non-local gravity\nby Shubha m Maheshwari (Groningen) as part of HEP seminars TU Wien (Vienna)\n\n\nAbs tract\nI consider higher derivative\, UV modifications to GR. In particula r\, I will focus on a specific kind of string theory-inspired higher deriv ative gravity where one includes derivatives to all orders in the action. First\, I will discuss how such a non-local theory of gravity admits stabl e\, non-singular bouncing solutions in the absence of matter. Moreover\, a round this bouncing background\, there exists only one propagating (and gh ost-free) scalar mode\, and no vector or tensor modes. Next\, I will discu ss the general analysis of scalar-vector-tensor perturbations in non-local gravity - in particular\, I will show how non-local gravity is ghost-free around (A)dS and certain non-maximally symmetric backgrounds\, and how ce rtain (A)dS backgrounds have special physical spectra in that the propagat ing degrees of freedom are different from usual expectations.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Bret Underwood (Pacific Lutheran University) DTSTART:20201029T150000Z DTEND:20201029T160000Z DTSTAMP:20260404T095653Z UID:HEPTUW/10 DESCRIPTION:Title: Cosmological Chaos\, Complexity\, and the OTOC\nby Bret Underwo od (Pacific Lutheran University) as part of HEP seminars TU Wien (Vienna)\ n\n\nAbstract\nSeveral approaches to investigating quantum chaos have rece ntly emerged\, including quantum circuit complexity and the out-of-time-or der correlator (OTOC). In this talk\, I will briefly introduce these ideas and apply them to squeezed states\, including the squeezed state descript ion of cosmological perturbations on a variety of cosmological backgrounds \, such as de Sitter accelerated expansion. Some intriguing results from t his investigation include a bound on the growth rate of cosmological compl exity reminiscent of a similar bound on the quantum Lyapunov exponent\, an d the observation that among all cosmological backgrounds\, only de Sitter space leads to the exponential growth of the OTOC that is a signature of quantum chaos.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Ashish Shukla (Perimeter) DTSTART:20201119T150000Z DTEND:20201119T160000Z DTSTAMP:20260404T095653Z UID:HEPTUW/11 DESCRIPTION:Title: The Effective Field Theory for Hydrodynamics and its Analytic Prope rties\nby Ashish Shukla (Perimeter) as part of HEP seminars TU Wien (V ienna)\n\n\nAbstract\nHydrodynamics provides an effective description for many-body systems near thermal equilibrium. The success of the paradigm re sts on the idea that the dynamics of such near-equilibrium systems can be captured by a very small number of parameters\, such as the temperature an d fluid velocity\, and their derivatives. For instance\, relativistic hydr odynamics\, which is applicable to systems which respect the Lorentz symme try\, has been immensely successful in understanding the properties of the Quark-Gluon plasma that is produced in heavy-ion collisions at RHIC and C ERN. In this talk\, I will start by reviewing the construction of hydrodyn amics in terms of a derivative expansion\, followed by a discussion of the equilibrium generating functional and its properties. Interestingly\, tho ugh the standard formulation of hydrodynamics captures the dissipative asp ects of the system quite well\, it does not take into account the effects of the underlying thermal fluctuations efficiently. One can remedy the sit uation to some extent by using the stochastic approach\, where one can int roduce random Gaussian fluctuations and derive an effective action. Howeve r\, this approach has its limitations\, as the structure of the interactio n terms in the effective action is quite restricted. Recently\, an effecti ve field theory (EFT) approach based on the Schwinger-Keldysh (SK) formali sm has been proposed\, which systematically captures the effects of the un derlying fluctuations\, making use of symmetries. In the second part of th e talk\, I will review the construction of the stochastic as well as the S K effective actions for a theory of charge diffusion. I will then discuss a simplifying limit of the SK diffusive EFT\, where the sound modes effect ively decouple from the dynamics. I will discuss one-loop corrections to t he retarded and symmetric correlators in this model\, with special emphasi s on the role played by the KMS symmetry in ensuring the correct analytic structure for the theory as required by the limit of thermal equilibrium\, providing a strong consistency check on the EFT framework.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Francesco Alessio (Naples) DTSTART:20201126T150000Z DTEND:20201126T160000Z DTSTAMP:20260404T095653Z UID:HEPTUW/12 DESCRIPTION:Title: Weyl symmetry and anomaly in asymptotically locally AdS_3\nby F rancesco Alessio (Naples) as part of HEP seminars TU Wien (Vienna)\n\n\nAb stract\nI will discuss an enhancement of Brown-Henneaux boundary condition s in 3d AdS General Relativity to encompass Weyl transformations of the bo undary metric. The consequences on the asymptotic symmetry algebra and the dual theory of imposing a conformally flat boundary condition are explore d. In particular\, I will show that the corresponding asymptotic symmetrie s include a new sector of Weyl rescalings with integrable but not conserve d surface charges. The holographic counterpart of this result can be consi stently described by an anomalous Ward-Takahashi identity in the boundary. \n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Juan Margalef-Bentabol (UCM) DTSTART:20201203T153000Z DTEND:20201203T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/13 DESCRIPTION:Title: Geometric formulation of covariant phase methods with boundary\ nby Juan Margalef-Bentabol (UCM) as part of HEP seminars TU Wien (Vienna)\ n\n\nAbstract\nIn physics\, one standard way to study and understand a the ory is through its dynamical formulation. Whenever possible\, this is obta ined by considering some initial conditions and evolving them through the dynamical equations of the theory. One gets then a curve over the space of initial conditions which codifies the evolution. This approach is useful in many settings\, including General Relativity (ADM\, numerical relativit y\, gravitational waves...)\, however\, it also has some limitations. Name ly\, to understand some non-local concepts such as black holes and their p roperties (e.g. spin\, energy\, or entropy) one runs into some complicatio ns. Another approach is to study the space of solutions where each point r epresents a whole solution of the theory. For well-posed problems\, this s pace is equivalent to the space of initial conditions (each initial condit ion gives rise to one and only one solution) although in general there wou ld be some gauge degeneracy (the solution is determined up to some gauge t ransformation). In this talk\, I will present this latter approach in what is known as the Covariant Phase Space methods. In particular\, I will sho w how to construct a presymplectic structure over the space of solutions c anonically associated with the action of the theory. The novelty of our wo rk is that we consider the manifold with boundary\, which adds several dif ficulties that had not been solved before.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Roberto Valandro (Trieste U.) DTSTART:20201217T153000Z DTEND:20201217T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/14 DESCRIPTION:Title: De Sitter vacua from anti-D3-branes in type IIB LVS compactificatio ns\nby Roberto Valandro (Trieste U.) as part of HEP seminars TU Wien ( Vienna)\n\n\nAbstract\nWe will begin with an introduction on moduli stabil isation in type IIB compactifications on CY orientifolds\, with de Sitter uplift due to an anti-D3 brane. We consider a concrete setup where an anti D3-brane sits at the tip of a warped throat and the stabilised volume is exponentially large as in the large volume scenario (LVS). We analyse the conditions on the parameters of the EFT such that they are in the region o f validity. We illustrate our results with an explicit choice of Calabi-Ya u manifold and D-brane configuration\, where moduli stabilisation gives ri se to a de Sitter minimum.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Pedro Aniceto (IST Lisbon) DTSTART:20210114T153000Z DTEND:20210114T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/15 DESCRIPTION:Title: R^2 corrected AdS_2 holography\nby Pedro Aniceto (IST Lisbon) a s part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nWe approach the pro blem of constructing the holographic dictionary for AdS_2/CFT_1 in the con text of higher derivative gravitational actions in AdS_2. We focus on S_2 reductions of four-dimensional N=2 Wilsonian effective actions with Weyl s quared interactions restricted to constant scalar backgrounds. BPS black h ole near-horizon spacetimes fall into this class of backgrounds and\, by i dentifying the boundary operators dual to the bulk fields\, we explicitly show how the Wald entropy of the BPS black hole is holographically encoded in the anomalous transformation of the operator dual to a composite bulk field. Additionally\, using a 2d/3d lift\, we show that the CFT holographi cally dual to AdS_2 is naturally embedded in the chiral half of the CFT_2 dual to the AdS_3 spacetime\, and we identify the specific CFT_1 operator that encodes the chiral central charge of the CFT_2.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Jakob Salzer (Harvard) DTSTART:20210128T153000Z DTEND:20210128T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/17 DESCRIPTION:Title: Limits of JT gravity\nby Jakob Salzer (Harvard) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nJackiw—Teitelboim (JT) gravity is a model of two-dimensional dilaton gravity that has been central to man y interesting developments (e.g.\, SYK model\, random matrix models\, isla nd proposal) in the last couple of years. In this talk I will discuss vari ous limits of JT gravity\, including Newton—Cartan (non-relativistic) an d Carrollian (ultra-relativistic) versions of two-dimensional dilaton grav ity. After defining suitable boundary conditions\, I will then discuss the issue of constructing boundary actions that capture the non-trivial dynam ics at the boundary of these models.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Sukruti Bansal (Chulangkorn University\, Bangkok) DTSTART:20210304T153000Z DTEND:20210304T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/18 DESCRIPTION:Title: Unimodular vs Nilpotent Superfield Approach to Pure dS Supergravity \nby Sukruti Bansal (Chulangkorn University\, Bangkok) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nRecent progress in understanding de Sitter spacetime in supergravity and string theory has led to the devel opment of a 4D supergravity with spontaneously broken supersymmetry allowi ng for de Sitter vacua\, also called de Sitter supergravity. One approach makes use of constrained (nilpotent) superfields\, while an alternative o ne couples supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action. These two approaches have been shown to gi ve rise to the same 4D action.\nA novel approach to de Sitter vacua in sup ergravity involves the generalisation of unimodular gravity to supergravi ty using a super-Stückelberg mechanism. We make a connection between this new approach and the previous two. We show that upon appropriate field re definitions\, the 4D actions match up to the cubic order in the fields. Th is points at the possible existence of a more general framework to obtain de Sitter spacetimes from high-energy theories.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Jakob Moritz (Cornell) DTSTART:20210311T153000Z DTEND:20210311T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/19 DESCRIPTION:Title: Resolving spacetime singularities in flux compactifications and KKL T\nby Jakob Moritz (Cornell) as part of HEP seminars TU Wien (Vienna)\ n\n\nAbstract\nI explain how string theory resolves ubiquitous singulariti es in type IIB flux compactifications (and eventually KKLT de Sitter vacua ) via effects that are non-perturbative in the \\alpha' expansion of strin g theory. I will show that these can be understood in detail by mapping th em to well known gauge instanton effects in pure 4d N=2 Yang-Mills theory. A perhaps surprising consequence is that the naively 'elementary' D7 bran e of type IIB string theory is properly thought of as a bound state of two mutually non-local cosmic defects in six dimensions upon compactification on a curved 4-manifold. Finally\, I will argue that the resolution descri bed indicates that KKLT de Sitter vacua can be controlled by a small flux superpotential although the K\\"ahler potential may in general receive lar ge corrections which are difficult to compute.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Kirill Boguslavski (TU Wien) DTSTART:20210325T153000Z DTEND:20210325T163000Z DTSTAMP:20260404T095653Z UID:HEPTUW/20 DESCRIPTION:by Kirill Boguslavski (TU Wien) as part of HEP seminars TU Wie n (Vienna)\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Angel Uranga (IFT Madrid) DTSTART:20210415T143000Z DTEND:20210415T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/21 DESCRIPTION:Title: Rolling down to the end of the world\nby Angel Uranga (IFT Madr id) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nWe discuss str ing theory configurations sitting on the slope of scalar potentials (aka t adpoles) and discuss properties of their spacetime dependent solutions. We argue that these solutions can extend only a finite distance away in the spacetime dimensions\, scaling as \\Delta^{-n}\\sim {\\cal T} with the str ength of the tadpole {\\cal T}. We show that naive singularities arising a t this distance scale are physically replaced by ends of spacetime\, relat ed to the cobordism defects of the swampland cobordism conjecture. We illu strate these phenomena in large classes of examples\, including susy and n on-susy 10 string theories and a 6d string model whose tadpole triggers sp ontaneous compactification to a semirealistic 3-family MSSM-like particle physics model.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Sucheta Majumdar (Université Libre de Bruxelles) DTSTART:20210422T143000Z DTEND:20210422T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/22 DESCRIPTION:Title: BMS symmetry in light-cone gravity\nby Sucheta Majumdar (Univer sité Libre de Bruxelles) as part of HEP seminars TU Wien (Vienna)\n\n\nAb stract\nThe aim of this talk is to discuss how the BMS symmetry appears in gravity in the light-cone gauge\, a formulation where all unphysical degr ees of freedom are integrated out. By checking the invariance of\nthe ligh t-cone Hamiltonian\, we obtain a set of residual gauge transformations tha t satisfy the BMS algebra realized on the two physical fields in the theor y. Hence\, the BMS algebra appears as a consequence of residual gauge inva riance in the bulk without any reference to asymptotic limits. Alternative ly\, one can also obtain the\nBMS algebra as a local extension of the Poin caré symmetry in light-cone gravity in four dimensions. In the light-cone formalism\, the dynamical part of the Poincaré algebra is enhanced to ac commodate the supertranslations\, yielding the infinite-dimensional BMS al gebra.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Kirill Boguslavski (TU Wien) DTSTART:20210429T143000Z DTEND:20210429T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/23 DESCRIPTION:Title: The imaginary part of the heavy-quark potential from real-time Yang -Mills dynamics\nby Kirill Boguslavski (TU Wien) as part of HEP semina rs TU Wien (Vienna)\n\n\nAbstract\nThe suppression of heavy quark-antiquar k bound states like bottomonium in heavy-ion collisions is an important ob servable for the quark-gluon plasma state. Theoretically\, this can be qua ntified by the heavy-quark potential. In this talk\, I will present our re sults on extracting its imaginary part using classical-statistical simulat ions of real-time Yang-Mills dynamics in classical thermal equilibrium. We compare our results to perturbation theory calculations in hard thermal l oop formalisms. We find that\, when considered as a function of m_D r\, wh ere m_D is the soft scale\, the imaginary part of the heavy-quark potentia l becomes independent of the lattice spacing at sufficiently small r and a grees well with perturbative results. We finally relate the short-distance behavior of the potential to the heavy-quark transport coefficient κ\, p roviding an estimate of the latter.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Anthony Ashmore (Chicago U. & Paris LPTHE) DTSTART:20210520T143000Z DTEND:20210520T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/24 DESCRIPTION:Title: Calabi-Yau metrics: what are they good for?\nby Anthony Ashmore (Chicago U. & Paris LPTHE) as part of HEP seminars TU Wien (Vienna)\n\n\n Abstract\nCalabi-Yau manifolds have played a key role in both mathematics and physics\, and are particularly important for deriving realistic models of particle physics from string theory. Unfortunately\, very little is kn own about the explicit metrics on these spaces\, leaving us unable\, for e xample\, to compute particle masses or couplings in these models. I will r eview recent progress in this direction on using numerical approximations to compute the metric and the (p\,q)-form Laplacian on these spaces. I wil l finish with some examples of what one can do with this new "data".\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Irene Valenzuela (Harvard) DTSTART:20210610T143000Z DTEND:20210610T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/25 DESCRIPTION:Title: Light Fermions and the Swampland\nby Irene Valenzuela (Harvard) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nQuantum gravity c an have important implications for Particle Physics and Cosmology. We cons ider constraints on D-dimensional theories in Minkowski\, dS and AdS backg rounds in the light of AdS swampland conjectures as applied to their compa ctication in a circle. In particular\, we consider the non-SUSY AdS instab ility conjecture and the AdS distance conjecture. For Minkowski and dS vac ua the results may be summarized by a light fermion conjecture which state s that in theories with a positive first non-vanishing supertrace $(-1)^{k +1}Str(M^{2k}) > 0$\, a surplus of light fermions with mass $m_f < \\Lambd a_D^{1/D}$ must be present\, where $\\Lambda_D$ is the cosmological consta nt. The case of AdS can be made consistent with the mild but not the stron g version of the AdS Distance conjecture. I will also apply the above cons traints to the Standard Model of particle physics\, obtaining that it woul d be inconsistent in Minkowski space but consistent in dS if the lightest neutrino is Dirac and lighter than the cosmological constant scale. This m ay shed some light into the naturalness issues observed in our universe.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Matthew Walters (EPF Lausanne) DTSTART:20210617T143000Z DTEND:20210617T153000Z DTSTAMP:20260404T095653Z UID:HEPTUW/26 DESCRIPTION:Title: Thermalization and Hydrodynamics in 2d QFTs\nby Matthew Walters (EPF Lausanne) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nI will discuss the finite-temperature behavior of general 2d QFTs (obtained as relevant deformations of CFTs). At long timescales (t >> 1/T)\, these t heories all have an effective hydrodynamic description governed by the KPZ universality class. Using KPZ universality and causality\, I will derive a lower bound on the timescale characterizing the onset of this hydrodynam ic behavior. The resulting bound is typically much longer than the expecte d quantum equilibration time of 1/T. I will also show how causality can be used to define a new thermodynamic C-function for 2d QFTs\, as well as co nstrain the sign of the "T-Tbar" term in EFTs.\n LOCATION:https://stable.researchseminars.org/talk/HEPTUW/26/ END:VEVENT END:VCALENDAR