BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Luca Delacretaz (University of Chicago) DTSTART:20200430T150000Z DTEND:20200430T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/1 DESCRIPTION:Title: Hydrodynamic Fluctuations\nby Luca Delacretaz (University of C hicago) as part of HoloTube: Applied holography webinars\n\nAbstract: TBA\ n LOCATION:https://stable.researchseminars.org/talk/HoloTube/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Eric Mefford (École Polytechnique Paris) DTSTART:20200505T150000Z DTEND:20200505T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/3 DESCRIPTION:Title: Transport in clean quantum critical superfluids\nby Eric Meffo rd (École Polytechnique Paris) as part of HoloTube: Applied holography we binars\n\n\nAbstract\nThe hydrodynamic regime of superfluids in systems li ke 4He has been well understood since the seminal work of Landau and Tisza . A fundamental assumption in much subsequent work is the low-temperature dominance of the superfluid phonon which leads to universal behavior in tr ansport that is characterized by the phonon sound speed. I will discuss in vestigations of the two-fluid model of superfluids near an underlying quan tum critical phase and establish criteria for the breakdown of this assump tion which leads to novel transport behavior. A surprising result is the n on-vanishing of the charge density of the fluid’s normal component at ze ro temperature. I will illustrate these results with some holographic mode ls.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Chandan Setty (University of Florida) DTSTART:20200512T140000Z DTEND:20200512T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/4 DESCRIPTION:Title: Pairing instability on Luttinger Surfaces : SYK thermodynamics fro m a condensed matter perspective\nby Chandan Setty (University of Flor ida) as part of HoloTube: Applied holography webinars\n\n\nAbstract\nSuper conductivity results from an instability of the Fermi surface — contour of poles of the single particle propagator — to an infinitesimally small attractive inter-particle attraction. In this talk\, I will instead discu ss the analogous problem on a model Luttinger Surface — contour of zeros of the Green function. Unlike a Fermi surface\, in the presence of an a ttractive potential\, the model exhibits a quantum phase transition from a non-Fermi liquid to a superconducting state. Crucially\, pair-fluctuatio ns close to the transition resemble well-studied models with gravity duals such as SYK. I will discuss implications of this result to microscopic mo dels describing Mott physics.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Richard Davison (Heriot-Watt University) DTSTART:20200519T140000Z DTEND:20200519T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/5 DESCRIPTION:Title: Relations between transport and chaos in holographic theories\ nby Richard Davison (Heriot-Watt University) as part of HoloTube: Applied holography webinars\n\n\nAbstract\nI will describe recent work illustratin g general relations between the transport properties and chaotic propertie s of quantum field theories with holographic duals. I will firstly show ho w a simple analysis of near-horizon dynamics yields exact constraints on t he spectrum of collective excitations. I will then describe how this can b e exploited to identify a universal feature in the spectrum\, and its impl ications for the collective transport properties of strongly interacting f ield theories with gravity duals.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Rene Meyer (University of Wurzburg) DTSTART:20200602T140000Z DTEND:20200602T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/7 DESCRIPTION:Title: Strongly correlated Dirac materials\, electron hydrodynamics & AdS /CFT\nby Rene Meyer (University of Wurzburg) as part of HoloTube: Appl ied holography webinars\n\n\nAbstract\nA current challenge in condensed ma tter physics is the realization of strongly correlated\, viscous electron fluids. These fluids are not amenable to the perturbative methods of Fermi liquid theory\, but can be described by holography\, that is\, by mapping them onto a weakly curved gravitational theory via gauge/gravity duality. The canonical system considered for realizations has been graphene\, whic h possesses Dirac dispersions at low energies as well as significant Coulo mb interactions between the electrons. In this talk\, after introducing ba sic notions of hydrodynamics and holography\, I will discuss Kagome system s which\, with electron fillings adjusted to the Dirac nodes of their band structure\, provide a much more compelling platform for realizations of viscous electron fluids\, including non-linear effects such as turbulence. In particular\, in stoichiometric Scandium (Sc) Herbertsmithite\, the fin e-structure constant\, which measures the effective Coulomb interaction an d hence reflects the strength of the correlations\, is enhanced by a facto r of about 3.2 as compared to graphene. I will present a holographic model which includes the leading finite coupling corrections and allows to esti mate the ratio of shear viscosity over entropy density in Sc-Herbertsmithi te\, and find it about three times smaller than in graphene. These finding s put\, for the first time\, the turbulent flow regime described by hologr aphy within the reach of experiments.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Matteo Baggioli (host) (IFT Madrid) DTSTART:20200526T140000Z DTEND:20200526T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/8 DESCRIPTION:Title: Discussion about the applications of Holography\nby Matteo Bag gioli (host) (IFT Madrid) as part of HoloTube: Applied holography webinars \n\n\nAbstract\nPanelists: Luca Delacretaz (Chicago)\, Blaise Gouteraux (P aris)\, Saso Grozdanov (MIT & Ljubljana)\, Carlos Hoyos (Oviedo)\, Koenraa d Schalm (Leiden)\, Jan Zaanen (Leiden).\n\nAfter more than a Decade of ef fort into holography and its applications\, it is a perfect moment to put\ nourselves on trial. What did we learn? What are we doing? And\, most impo rtantly\, what are we going to do next? With the help of the top experts i n the community\, we will try to address all of the above questions in an interactive panel discussion. As a moderator\, I will propose specific and concrete questions about the last developments in the subject. All partic ipants are highly encouraged to bring\ntheir own questions and interact du ring the panel discussion.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Ayan Mukhopadhyay (Indian Institute Of Technology Madras) DTSTART:20200609T140000Z DTEND:20200609T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/9 DESCRIPTION:Title: SL(2\,R) lattices and networks as information mirrors and decoders \nby Ayan Mukhopadhyay (Indian Institute Of Technology Madras) as part of HoloTube: Applied holography webinars\n\n\nAbstract\nQuantum black hol es past their Page times are unique objects in terms of how they process q uantum information. Thinking of such black holes as quantum circuits\, it has been argued that while infalling information after Page time comes out quickly at the order of Hayden-Preskill time\, processing the information about the black hole interior will require timescales that are much large r than the evaporation time of the black hole in order to avoid informatio n paradoxes. Thus quantum black holes acts as information mirrors that rev eals the bits that fell in just after Page time first and its own formatio n later. Motivated by the fragmented horizon picture\, we construct a simp le model that can capture the essence of quantum black holes in terms of i ts information processing. Our model is a lattice of nearly two-dimensiona l anti-de Sitter spaces interacting with mobile quantum hair carrying grav itational charges. We will show that this model can realize the Hayden-Pre skill protocol while not encountering information paradoxes due to inheren t pseudorandomness and scrambling. Furthermore\, we will discuss well moti vated generalizations of this model that are analogous to tensor networks. We will argue these can provide computable “fragmented holographic” frameworks for general semi-local non-Fermi liquids and other strongly cor related systems.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Umut Gürsoy (University of Utrecht) DTSTART:20200616T140000Z DTEND:20200616T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/10 DESCRIPTION:Title: Holography of the spin current\nby Umut Gürsoy (University o f Utrecht) as part of HoloTube: Applied holography webinars\n\n\nAbstract\ nRecent developments both in high and low energy physics have increased th e importance of hydrodynamics of matter with correlated spin degrees of fr eedom. In particular\, Takahashi et al managed to create stable spin curre nts in liquid metals sourced by vorticity\, and the STAR collaboration at RHIC observed nontrivial polarization of hyperon particles in off-central heavy ion collisions. Theoretical understanding of these findings requires adding the spin current to (relativistic) hydrodynamics as a new degree o f freedom. In this talk — that will be based on arXiv:2004.05148 — I will describe how this can be done by sourcing the spin current by torsion . I will classify different types of torsion in 3+1 dimensions and develop the corresponding constitutive equations for the energy-momentum tensor a nd the spin current. We will then analyze the problem in a toy holographic model based on the 5D Lovelock-Chern-Simons theory. As a byproduct\, I wi ll introduce a number of previously unknown blackhole solutions to this t heory and map these solutions to hydrodynamics by the fluid-gravity corres pondence. The resulting energy-momentum and spin flow exhibits interesting features including a dynamical version of the Barnett effect and indicate various novel mechanisms through which spin currents may be generated in strongly correlated systems.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Sera Cremonini (University of Lehigh) DTSTART:20200623T140000Z DTEND:20200623T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/11 DESCRIPTION:Title: Constraining Non-Relativistic RG Flows with Holography\nby Se ra Cremonini (University of Lehigh) as part of HoloTube: Applied holograph y webinars\n\n\nAbstract\nThe basic question of how to organize the degree s of freedom of a quantum system as a function of energy scale has proven very difficult to address in a general context. The powerful c-theorems\, for example\, which provide a clear measure for the number of effective de grees of freedom through the existence of a monotonic c-function\, rely cr ucially on Lorentz invariance. In this talk I will discuss attempts to ide ntify potential generalizations of a c-function within the context of non- relativistic holographic RG flows. In particular\, I will examine Einstein -Maxwell-scalar theories that support geometries that are not Lorentz inva riant at all energy scales\, and identify several quantities that behave m onotonically along RG flow. While some results are completely generic in E instein-Maxwell-scalar theories\, others will only hold in Einstein-scalar theories.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Moshe Rozali (UBC Vancouver) DTSTART:20200630T140000Z DTEND:20200630T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/12 DESCRIPTION:Title: Effective Field Theory for Chaotic CFTs\nby Moshe Rozali (UBC Vancouver) as part of HoloTube: Applied holography webinars\n\n\nAbstract \nRelations between chaos and hydrodynamics are one of the unique feature of holographic CFTs. The early time Lyapunov regime can described by an ef fective field theory of a single mode\, which for maximally chaotic system s is an hydrodynamic mode. We describe that effective field theory for con formal field theories\, both in two dimensions and in higher dimensions\, and show how it captures maximal chaos and pole skipping. We discuss the r elation of the theory to other formulations of CFTs and show how it captur es interesting objects such as conformal blocks and partial waves. We spec ulate on what is needed to extend the discussion to non maximal chaos.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Rajeev Singh (Institute of Nuclear Physics Polish Academy of Scien ces) DTSTART:20200707T140000Z DTEND:20200707T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/13 DESCRIPTION:Title: A new hydrodynamics with spin formalism for the description of po larization effect of Lambda hyperons\nby Rajeev Singh (Institute of Nu clear Physics Polish Academy of Sciences) as part of HoloTube: Applied hol ography webinars\n\n\nAbstract\nMeasurements made recently by the STAR col laboration show that the Lambda hyperons produced in relativistic heavy-io n collisions are subject to global spin polarization with respect to an ax is coincident with the axis of rotation of the produced matter. Recently f ormulated formalism of relativistic hydrodynamics with spin\, which is a g eneralization of the standard hydrodynamics\, is a natural tool for descri bing the evolution of such systems. This approach is based on the conserva tion laws and the form of the energy-momentum tensor and spin tensor postu lated by de Groot\, van Leeuwen\, and van Weert (GLW). Using Bjorken symme try we show how this formalism may be used to determine observables descri bing the polarization of particles measured in the experiment.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Alexander Krikun (Nordita) DTSTART:20200714T140000Z DTEND:20200714T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/14 DESCRIPTION:Title: Coherent and incoherent transport in holographic models with spon taneously broken translations\nby Alexander Krikun (Nordita) as part o f HoloTube: Applied holography webinars\n\n\nAbstract\nIn holography it is relatively easy to construct the models which break translation symmetry either explicitly\, or spontaneously\, or both. AC transport in these mode ls has a few interesting features\, which were in focus for the past few y ears\, including the gapped “pseudo-Goldstone” mode\, the metal — Mo tt insulator transition\, the residual incoherent conductivity and the con tribution of the gapped coherent peak in DC conductivity due to “phase r elaxation”. It is particularly interesting to study these features in de tail\, since they might have a direct representation in the experimental d ata on cuprates and doped Mott insulators. I will overview the subject and present several recent observations in models with either helical or peri odic holographic lattices\, which shed some light on the physics behind th ese interesting features.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Kévin Nguyen (Harvard University) DTSTART:20200721T140000Z DTEND:20200721T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/15 DESCRIPTION:Title: Superluminal chaos after a quantum quench\nby Kévin Nguyen ( Harvard University) as part of HoloTube: Applied holography webinars\n\n\n Abstract\nI will present a formula to compute out-of-time-order correlator s (OTOC) in generic asymptotically AdS spacetimes\, based on the geodesic approximation to bulk propagators and the exchange of gravitational shock waves. In contrast to the standard method of Shenker and Stanford\, this f ormula does not require to work in Fourier space and is therefore better s uited when considering time-dependent holographic states. Applying this ne w method to the computation of OTOCs in quenched states dual to collapsing thin shells of matter (Vaidya spacetimes)\, we discover a transient super luminality in the butterfly velocity characterizing information scrambling in the system.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Mario Flory (Jagiellonian University) DTSTART:20200728T140000Z DTEND:20200728T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/16 DESCRIPTION:Title: Complexity and Conformal Field Theory\nby Mario Flory (Jagiel lonian University) as part of HoloTube: Applied holography webinars\n\n\nA bstract\nWe study circuit and state complexity in the universal setting of (1+1)-dimensional conformal ​ field theory and unitary transformations generated by the stress-energy tensor. We provide a unifi​ed view of ass igning a cost to circuits based on the Fubini-Study metric\, iteratively s olve the emerging integro-diff​erential equation for sample optimal circ uits and discuss the sectional curvature of the underlying geometry. We al so discuss the relation of our work to Euler-Arnold type equations such as the Korteweg-de Vries and Hunter-Saxton equations.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Jelle Hartong (University of Edinburgh) DTSTART:20200901T140000Z DTEND:20200901T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/17 DESCRIPTION:Title: Dynamics of Fluids without Boost Symmetries\nby Jelle Hartong (University of Edinburgh) as part of HoloTube: Applied holography webinar s\n\n\nAbstract\nStandard textbook treatments of fluid dynamics assume the presence of a boost symmetry. This is either a Galilean boost symmetry or a Lorentzian one and leads to the Navier-Stokes equations or their relati vistic counterpart. It is however not necessary to rely on a boost symmetr y as one can treat velocity as the chemical potential associated with mome ntum conservation. In fact for fluids moving through a medium one expects boost symmetries to be generically broken. This includes the case of scale invariant Lifshitz fluids. In this talk I will present the general treatm ent of fluid dynamics without boost symmetries and I will show that there can be 10 dissipative and 6 non-dissipative transport coefficients (of whi ch 2 are hydrostatic and 4 are not) for uncharged non-boost invariant flui d dynamics. I will end with some comments regarding holographic realisatio ns of non-boost invariant Lifshitz fluids.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/17/ END:VEVENT BEGIN:VEVENT SUMMARY:Danny Brattan (University of Genova) DTSTART:20200908T140000Z DTEND:20200908T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/18 DESCRIPTION:Title: Diffusion in a magnetic field\nby Danny Brattan (University o f Genova) as part of HoloTube: Applied holography webinars\n\n\nAbstract\n Even with the simplifying assumption of non-dynamical (external) electroma gnetic fields\, magnetohydrodynamics is a technically subtle framework for understanding the long wavelength and low frequency regime of interacting theories. One of these technicalities is that for many models of interdis ciplinary relevance the magnetic field is a constant in equilibrium. Intui tively however\, for momentum to be approximately conserved and enter the hydrodynamic description\, the magnetic field must vanish at leading order .\n\nIn this talk I will review recent work that sheds light on some of th e unique features of magnetohydrodynamics in (2+1)-dimensions\, with a par ticular emphasis on diffusion. I will show that there is a qualitative and quantitative improvement in matching holographic and hydrodynamic correla tors if one correctly accounts for the magnetic field being non-zero in th e background. Consequently\, I will give conclusive evidence that there is a non-zero incoherent Hall conductivity in the absence of parity violatio n that was missed in previous approaches. Finally\, I will discuss some wa ys in which this new approach can be applied to non-stringy systems.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Paul Romatschke (University of Colorado Boulder) DTSTART:20200915T140000Z DTEND:20200915T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/19 DESCRIPTION:Title: Hydrodynamics Off Equilibrium\nby Paul Romatschke (University of Colorado Boulder) as part of HoloTube: Applied holography webinars\n\n \nAbstract\nHaving a thermalized system is the textbook requirement for th e applicability of hydrodynamics. However\, there is mounting evidence tha t hydrodynamics offers a good quantitative description even in off-equilib rium situations. Recent applications of resurgence to relativistic fluid d ynamics in the context of conformal systems is able to put the new\, gener alized theory of off-equilibrium fluid dynamics on solid theoretical footi ng\, without requiring near local equilibrium or even isotropy. This offer s a tempting explanation for\nthe ‘unreasonable success’ of hydrodynam ics in describing experimental data for p+p and p+A collisions.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Aldo Cotrone (University of Firenze) DTSTART:20200922T140000Z DTEND:20200922T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/20 DESCRIPTION:Title: Holographic QCD and Gravitational Waves\nby Aldo Cotrone (Uni versity of Firenze) as part of HoloTube: Applied holography webinars\n\n\n Abstract\nI will first review basic properties of the Sakai-Sugimoto model \, the top-down holographic theory closest to QCD. Then\, in this model I will describe the process of nucleation of bubbles of true vacua in the ca se of two first-order transitions: the confinement/deconfinement and chira l symmetry breaking/restoration ones. Finally\, using these information\, I will present the calculation of the gravitational wave spectra generated in these transitions\, when the Sakai-Sugimoto model is employed as a dar k sector. Prospects of detection will be discussed.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/20/ END:VEVENT BEGIN:VEVENT SUMMARY:John McGreevy (University of California at San Diego) DTSTART:20200929T160000Z DTEND:20200929T170000Z DTSTAMP:20260404T111245Z UID:HoloTube/21 DESCRIPTION:Title: How right was Landau?\nby John McGreevy (University of Califo rnia at San Diego) as part of HoloTube: Applied holography webinars\n\n\nA bstract\nThe Landau paradigm for phases of matter and transitions between them has been very successful. It is even more successful if we extend it to include higher-form symmetries. I will discuss some applications of th is way of thinking about the world. This includes revisiting the idea that the 3d Ising model is a string theory.\n(Based on work with Nabil Iqbal.) \n LOCATION:https://stable.researchseminars.org/talk/HoloTube/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrei Starinets (University of Oxford) DTSTART:20201006T140000Z DTEND:20201006T150000Z DTSTAMP:20260404T111245Z UID:HoloTube/22 DESCRIPTION:by Andrei Starinets (University of Oxford) as part of HoloTube : Applied holography webinars\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Amoretti (University of Genoa) DTSTART:20201103T150000Z DTEND:20201103T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/23 DESCRIPTION:Title: Holography\, hydrodynamics and condensed matter experiments: a cr itical overview\nby Andrea Amoretti (University of Genoa) as part of H oloTube: Applied holography webinars\n\n\nAbstract\nIn this talk I will re view the progress that has been done in the last year in the description o f strongly coupled condensed matter electron systems by means of hydrodyna mic and holographic effective field theories\, focusing particularly on th e experimental results. Particular attention will be put on recent results on high temperature superconductors. In the final part of the talk I will try to emphasize open questions and possible future directions.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Cindy Keeler (Arizona State University) DTSTART:20201110T170000Z DTEND:20201110T180000Z DTSTAMP:20260404T111245Z UID:HoloTube/24 DESCRIPTION:Title: Towards a general map from Navier-Stokes to Maxwell via Einstein< /a>\nby Cindy Keeler (Arizona State University) as part of HoloTube: Appli ed holography webinars\n\n\nAbstract\nAfter a brief review of the cutoff-s urface formulation of fluid-gravity duality\, we explore the “square roo t” of the fluid-dual metrics via the classical-double copy\, highlightin g the constant vorticity flows and potential flows which have algebraicall y special Weyl double copy fields. We then present progress towards buildi ng the same map\, from fluid solutions to gravitational solutions to Maxwe ll solutions\, for generic fluids in 2+1 dimensions. This talk is based on JHEP 08 (2020) 147 published with ASU students Nikhil Monga and Tucker Ma nton\, and forthcoming work\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Ben Withers (University of Southampton) DTSTART:20201117T150000Z DTEND:20201117T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/25 DESCRIPTION:Title: Does the hydrodynamic expansion converge?\nby Ben Withers (Un iversity of Southampton) as part of HoloTube: Applied holography webinars\ n\n\nAbstract\nThis is one of the foundational questions in relativistic f luid mechanics\, and concerns the properties of a gradient expansion at la rge orders. Holographic theories provide the ideal testing ground for this question\, since hundreds of orders in the expansion can be obtained with relative ease. Famously\, the answer was found to be “No” for the Bjo rken flow\, an expanding plasma considered in position space. In this talk I will begin by reviewing earlier work\, in which I show that the answer is instead “Yes” for QNM dispersion relations in momentum space\, with a radius of convergence set by mode collisions in the complex momentum pl ane. I will then present recent work showing that these hitherto disjoint avenues of research are naturally unified\, and share a common underlying mechanism governing convergence.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Ya-Wen Sun (UCAS Beijing) DTSTART:20201124T150000Z DTEND:20201124T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/26 DESCRIPTION:Title: Topological modes in hydrodynamics and holography\nby Ya-Wen Sun (UCAS Beijing) as part of HoloTube: Applied holography webinars\n\n\nA bstract\nIn this talk I will show that gapless modes in relativistic hydro dynamics could become topologically nontrivial by weakly breaking the cons ervation of energy momentum tensor in a specific way. This system has topo logical semimetal-like crossing nodes in the spectrum of hydrodynamic mode s that require the protection of a special combination of translational an d boost symmetries in two spatial directions. One possible origin for the non-conservation terms of the energy momentum tensor is an external gravit ational field which could be generated by a specific coordinate transforma tion from the flat spacetime. This suggests that topologically trivial mod es could become topologically nontrivial by being observed in a special no n-inertial reference frame. Finally a holographic realization of this syst em will be introduced.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Glorioso\, Heller\, Kovtun\, Withers DTSTART:20201201T160000Z DTEND:20201201T170000Z DTSTAMP:20260404T111245Z UID:HoloTube/27 DESCRIPTION:Title: Panel on "Hydrodynamics\, out-of-equilibrium physics and holograp hy"\nby Glorioso\, Heller\, Kovtun\, Withers as part of HoloTube: Appl ied holography webinars\n\n\nAbstract\nHosts: Navid Abbasi and Matthias Ka minski (HoloTube Team)\n\nPanelists: Pavel Kovtun (University of Victoria) \, Michal Heller (Max Planck Institute for Gravitational Physics\, Postdam )\, Paolo Glorioso (Stanford)\, Ben Withers (Southampton University)\n\nTi tle: Discussion about Hydrodynamics\, Out-of-Equilibrium Physics and Holog raphy\n\nAbstract: In the recent two decades\, hydrodynamics has been syst ematically studied as a low energy effective field theory (EFT)\, which is an expansion into operators and their derivatives. This EFT has been exte nded in many directions by: including the effect of interactions\, examini ng the convergence of its dispersion relations\, re-summing the derivative expansion\, connecting it to gravity\, pushing it forward to far from equ ilibrium situations\, establishing its causality and stability conditions\ , and deriving it from a generating functional. In this panel discussion\, with four experts we assess the status and prospects of this field.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Jorge Noronha (University of Illinois) DTSTART:20201215T150000Z DTEND:20201215T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/28 DESCRIPTION:Title: Holography and the Quark-Gluon Plasma: The Next Decade\nby Jo rge Noronha (University of Illinois) as part of HoloTube: Applied holograp hy webinars\n\n\nAbstract\nIn this talk I will critically review the role played by holography in our current understanding of the quark-gluon plasm a (QGP) formed in heavy-ion collisions. Outstanding challenges regarding t he hydrodynamic behavior of the QGP will be presented\, considering the dy namical inclusion of critical phenomena and\, especially\, concerning the modeling of the collective behavior displayed by small collision systems s uch as proton-nucleus and proton-proton collisions. New opportunities to i mprove the holographic modeling of the QGP\, in and out-of-equilibrium\, w ill be discussed.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Sayantani Bhattacharyya (NISER\, India) DTSTART:20201208T150000Z DTEND:20201208T160000Z DTSTAMP:20260404T111245Z UID:HoloTube/29 DESCRIPTION:Title: Entropy current for higher derivative theories of gravity\nby Sayantani Bhattacharyya (NISER\, India) as part of HoloTube: Applied holo graphy webinars\n\n\nAbstract\nWe know that black holes could be viewed as thermodynamic ensemble of large number of microstates and therefore we co uld associate some entropy with these objects. For Einstein gravity\, the local area element around any point of the black hole horizon plays the ro le of entropy density\, that satisfies the second law of thermodynamics lo cally at every point on the horizon. However\, any UV complete theory of g ravity\, in its low energy limit\, will typically have higher derivative c orrections to Einstein gravity. Black holes continue to exist for such hig her derivative theories. In this talk\, we shall show that for such theori es we could still satisfy the second law locally on every point of the hor izon\, at least when the dynamics of the black hole is of small amplitude. To see this\, we need to add a spatial entropy current to the equilibrium construction of Wald entropy density. This method also fixes some of the ambiguities that arise in Wald’s construction\, for the entropy of a dyn amical black hole in higher derivative theories.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Glorioso\, Heller\, Kovtun\, Withers DTSTART:20201210T160000Z DTEND:20201210T180000Z DTSTAMP:20260404T111245Z UID:HoloTube/30 DESCRIPTION:Title: Panel on "Hydrodynamics\, out-of-equilibrium physics and holograp hy". Part II\nby Glorioso\, Heller\, Kovtun\, Withers as part of HoloT ube: Applied holography webinars\n\n\nAbstract\nHosts: Navid Abbasi and Ma tthias Kaminski (HoloTube Team)\n\nPanelists: Pavel Kovtun (University of Victoria)\, Michal Heller (Max Planck Institute for Gravitational Physics\ , Postdam)\, Paolo Glorioso (Stanford)\, Ben Withers (Southampton Universi ty)\n\nTitle: Discussion about Hydrodynamics\, Out-of-Equilibrium Physics and Holography\n\nAbstract: In the recent two decades\, hydrodynamics has been systematically studied as a low energy effective field theory (EFT)\, which is an expansion into operators and their derivatives. This EFT has been extended in many directions by: including the effect of interactions\ , examining the convergence of its dispersion relations\, re-summing the d erivative expansion\, connecting it to gravity\, pushing it forward to far from equilibrium situations\, establishing its causality and stability co nditions\, and deriving it from a generating functional. In this panel dis cussion\, with four experts we assess the status and prospects of this fie ld.\n LOCATION:https://stable.researchseminars.org/talk/HoloTube/30/ END:VEVENT END:VCALENDAR