BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Michele Del Zotto (Uppsala) DTSTART:20220308T150000Z DTEND:20220308T160000Z DTSTAMP:20260422T225702Z UID:SymSem/1 DESCRIPTION:Title: G lobal structures from the infrared\nby Michele Del Zotto (Uppsala) as part of Symmetry Seminar\n\n\nAbstract\nQuantum field theories with identi cal local dynamics can admit different choices of global structure\, leadi ng to different partition functions and spectra of extended operators. Rec ent work has determined the structure of such choices via stringy geometri c methods for various classes of Lagrangian and non-Lagrangian theories. I n this talk I will discuss a purely field theoretical counterpart of this analysis\, showing that global structures can be captured from a careful a nalysis of the infrared Coulomb-like phases. Our results confirm and exten d the many results obtained within geometric engineering about the global structures of Argyres-Douglas theories\, 5d SCFTs and 6d SCFTs.\n LOCATION:https://researchseminars.org/talk/SymSem/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Justin Kaidi (SCGP) DTSTART:20220315T140000Z DTEND:20220315T150000Z DTSTAMP:20260422T225702Z UID:SymSem/2 DESCRIPTION:Title: K ramers-Wannier-like duality defects in (3+1)d gauge theories\nby Justi n Kaidi (SCGP) as part of Symmetry Seminar\n\n\nAbstract\nI will introduce a class of non-invertible topological defects in (3+1)d gauge theories wh ose fusion rules are the higher-dimensional analogs of those of the Kramer s-Wannier defect in the (1+1)d critical Ising model. As in the lower-dimen sional case\, the presence of such non-invertible defects implies self-dua lity under a particular gauging of the discrete (higher-form) symmetries. I will illustrate this by means of the examples of SO(3) Yang-Mills at θ= π\, as well as SU(2)N=4 SYM at τ=i.\n LOCATION:https://researchseminars.org/talk/SymSem/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Ho Tat Lam (MIT) DTSTART:20220412T150000Z DTEND:20220412T160000Z DTSTAMP:20260422T225702Z UID:SymSem/3 DESCRIPTION:Title: N on-invertible Condensation\, Duality and Triality Defects in 3+1d\nby Ho Tat Lam (MIT) as part of Symmetry Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/SymSem/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Du Pei (Harvard) DTSTART:20220419T150000Z DTEND:20220419T160000Z DTSTAMP:20260422T225702Z UID:SymSem/4 DESCRIPTION:Title: O n Symmetries of 2d TQFTs and the Equivariant Verlinde Formula\nby Du P ei (Harvard) as part of Symmetry Seminar\n\n\nAbstract\nIn this talk\, we will discuss (generalized) symmetries of 2d semisimple TQFTs. We will show that\, in a special basis\, the 0-form symmetries always act as permutati ons while 1-form symmetries act by phases. This leads to an explicit descr iption of the gauging of these symmetries. These results can be used to be tter understand compactifications of 6d (2\,0) theories. In particular\, w e will use it to generalize the equivariant Verlinde formula to the case o f general Lie groups\, which leads to many predictions for the geometry of Hitchin moduli spaces.\n LOCATION:https://researchseminars.org/talk/SymSem/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Ibrahima Bah (JHU) DTSTART:20220322T150000Z DTEND:20220322T160000Z DTSTAMP:20260422T225702Z UID:SymSem/5 DESCRIPTION:by Ibrahima Bah (JHU) as part of Symmetry Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/SymSem/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Ibou Bah (JHU) DTSTART:20220405T150000Z DTEND:20220405T160000Z DTSTAMP:20260422T225702Z UID:SymSem/6 DESCRIPTION:Title: G eometry of decoupled fields\nby Ibou Bah (JHU) as part of Symmetry Sem inar\n\n\nAbstract\nAbstract: In this talk I will discuss aspects of flipp ed fields that appear in the engineering of 4d SCFTs from compactification s of 6d (1\,0) SCFTs of A_(N-1) type. By studying various ways of constru cting the anomaly polynomial for the 4d theory\, it is possible to account for flipped fields when the 6d SCFT is compactified on a Riemann surface. I will also discuss their geometric origin and their role along the RG f low.\n LOCATION:https://researchseminars.org/talk/SymSem/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Apoorv Tiwari (KTH) DTSTART:20220426T150000Z DTEND:20220426T160000Z DTSTAMP:20260422T225702Z UID:SymSem/7 DESCRIPTION:Title: T opological Holography: Unifying Conventional and Unconventional Quantum Ph ase Transitions\nby Apoorv Tiwari (KTH) as part of Symmetry Seminar\n\ n\nAbstract\nIn this talk\, I will describe an approach that uses an auxil iary D+1-dimensional topological order\, typically a topological gauge the ory\, to extract non-perturbative statements about the quantum phases and phase transitions realized in D-dimensional quantum systems with a fixed g lobal symmetry structure. I will exemplify this approach for D=1 and for t he case where the symmetry structure corresponds to a finite Abelian group .\n LOCATION:https://researchseminars.org/talk/SymSem/7/ END:VEVENT BEGIN:VEVENT SUMMARY:Lorenzo di Pietro (Trieste) DTSTART:20220503T150000Z DTEND:20220503T160000Z DTSTAMP:20260422T225702Z UID:SymSem/8 DESCRIPTION:Title: F actorization and Global symmetry in holography\nby Lorenzo di Pietro ( Trieste) as part of Symmetry Seminar\n\n\nAbstract\nBased on 2203.09537. I n the context of toy models of holography arising from 3d Chern-Simons the ory\, I will describe an approach in which\, rather than summing over bulk geometries\, one gauges a one-form global symmetry of the bulk theory. Th is ensures that the bulk theory has no global symmetries\, and it makes th e partition function on spacetimes with boundaries coincide with that of a modular-invariant 2d CFT on the boundary. In particular\, on wormhole geo metries one finds a factorized answer for the partition function\n LOCATION:https://researchseminars.org/talk/SymSem/8/ END:VEVENT BEGIN:VEVENT SUMMARY:Dongmin Gang (Seoul) DTSTART:20220510T150000Z DTEND:20220510T160000Z DTSTAMP:20260422T225702Z UID:SymSem/9 DESCRIPTION:Title: I nfrared phases of 3D class R theories\nby Dongmin Gang (Seoul) as part of Symmetry Seminar\n\n\nAbstract\nWe study IR phases of 3D class R theor y associated to closed non-hyperbolic 3-manifolds. Non-hyperbolic 3-manifo lds can be obtained by performing Dehn fillings on 1-cusped hyperbolic 3- manifolds along exceptional slopes. In 3D-3D correspondence\, the `excepti onal' Dehn filling corresponds to the gauging of an SU(2) flavor symmetry in a superconformal field theory associated to a 1-cusped 3-manifold with `small' Chern-Simons levels. With several explicit examples\, we analyze various interesting non-perturbative IR phenomena (such as spontaneous SU SY breaking\, generation of mass gap and supersymmetry enhancement) from the `exceptional' gaugings. Interestingly\, distinguished features of t he IR phases can be captured by simple topological properties of non-hyper bolic 3-manifolds. We also find that 3D class R theories associated to cer tain classes of atoroidal non-hyperbolic manifolds always exhibit supersym metry enhancement at low energy and actually flow to 3D rank 0 N=4 SCFTs with trivial vacuum moduli space.\n LOCATION:https://researchseminars.org/talk/SymSem/9/ END:VEVENT BEGIN:VEVENT SUMMARY:Ben Gripaios (Cambridge) DTSTART:20220726T150000Z DTEND:20220726T160000Z DTSTAMP:20260422T225702Z UID:SymSem/10 DESCRIPTION:Title: Generalized symmetries of topological field theories\nby Ben Gripaios (Cambridge) as part of Symmetry Seminar\n\n\nAbstract\nI describe joint wo rk\, with Oscar Randal-Williams and Joseph Tooby-Smith\, studying generali zed symmetries in a simplified arena in which the usual quantum field theo ries of physics are replaced with topological field theories and the smoot h structure with which the symmetry groups of physics are usually endowed is forgotten. Doing so allows many questions of physical interest to be an swered using the tools of homotopy theory. We study both global and gauge symmetries\, as well as two types of `t Hooft anomaly. Our approach also a llows some insight into earlier work on symmetries (generalized or not) of topological field theories.\n LOCATION:https://researchseminars.org/talk/SymSem/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Yunqin Zheng (IPMU) DTSTART:20220621T150000Z DTEND:20220621T160000Z DTSTAMP:20260422T225702Z UID:SymSem/11 DESCRIPTION:by Yunqin Zheng (IPMU) as part of Symmetry Seminar\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/SymSem/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Craig Lawrie (DESY) DTSTART:20220517T150000Z DTEND:20220517T160000Z DTSTAMP:20260422T225702Z UID:SymSem/12 DESCRIPTION:Title: Global Structures in 6d (1\,0) SCFTs and Their Implications for 4d\nby Craig Lawrie (DESY) as part of Symmetry Seminar\n\n\nAbstract\nWe explore the global structure of the global symmetry group across the vast landsca pe of 6d (1\,0) SCFTs. Many of the known 6d SCFTs fall into families relat ed by Higgs branch deformations\, where the deformations are associated to either a nilpotent orbit\, or a homomorphism from a finite group into E_8 \; we determine how the flavor group can be written simply in terms of thi s data. A large class of novel 4d N=2 SCFTs can be obtained by compactifyi ng these 6d (1\,0) SCFTs with non-simply-connected flavor group on a torus in the presence of a topologically non-trivial flat flavor bundle charact erized by a 't Hooft magnetic flux. We explore the properties of the resul ting 4d theories and highlight where there is overlap with previously stud ied constructions\, such as class S and the N=2 S-folds.\n LOCATION:https://researchseminars.org/talk/SymSem/12/ END:VEVENT BEGIN:VEVENT SUMMARY:Yichul Choi (Stony Brook) DTSTART:20220531T150000Z DTEND:20220531T160000Z DTSTAMP:20260422T225702Z UID:SymSem/13 DESCRIPTION:Title: Higher Berry Phase of Free Dirac Fermions\nby Yichul Choi (Stony Brook ) as part of Symmetry Seminar\n\n\nAbstract\nThe infrared fixed point of a trivially gapped quantum field theory is described by an invertible field theory\, which captures its response to various external background field s. The set of background fields can include spacetime-dependent coupling c onstants\, in which case we call the corresponding invertible theory a par ameterized invertible field theory. The partition function of a parameteri zed invertible field theory is called a higher Berry phase\, as it capture s the response of the theory to the adiabatic variation of the coupling co nstants across spacetime. I'll discuss a class of such parameterized inver tible field theories arising from free Dirac fermions with spacetime-depen dent mass parameters. The universal form of the higher Berry curvature wil l be derived using the APS index theorem\, and an example of a nontrivial parameterized invertible theory with a vanishing Berry curvature will be e xplained.\n LOCATION:https://researchseminars.org/talk/SymSem/13/ END:VEVENT BEGIN:VEVENT SUMMARY:Irene Valenzuela (CERN) DTSTART:20220628T140000Z DTEND:20220628T150000Z DTSTAMP:20260422T225702Z UID:SymSem/14 DESCRIPTION:Title: What can we learn from the absence of global symmetries?\nby Irene Val enzuela (CERN) as part of Symmetry Seminar\n\n\nAbstract\nIn this talk I w ill explain some of the implications that the absence of global symmetries can have for the dynamics of the theory. I will review the reasoning behi nd the absence of global symmetries in quantum gravity\, which is equivale nt to requiring the absence of non-trivial topologocial operators. I will then explain how many string theory features can be derived from this stat ement\, including completeness of the charge spectra\, the existence of lo calised worldvolume degrees of freedom on defects and the presence of axio ns.\n LOCATION:https://researchseminars.org/talk/SymSem/14/ END:VEVENT BEGIN:VEVENT SUMMARY:Theo Johnson-Freyd (Perimeter) DTSTART:20221004T140000Z DTEND:20221004T150000Z DTSTAMP:20260422T225702Z UID:SymSem/15 DESCRIPTION:Title: A 4D TQFT which is not (quite) a gauge theory\nby Theo Johnson-Freyd ( Perimeter) as part of Symmetry Seminar\n\n\nAbstract\nSome people have acc used me of proving that every (nice enough) 4D TQFT is equivalent to a gau ge theory. A version of this statement is true\, but only if your notion o f "gauge theory" allows dynamical spin structures among the "gauge fields" \, and some rather complicated terms in the Lagrangian that couple the spi n structures to the other gauge fields. That said\, many of these 4D TQFTs also admit "dual" descriptions as true gauge theories for higher-form gro ups. In this talk\, I will explain exactly which 4D TQFTs are equivalent t o true (higher-group) gauge theories theories\, and present a minimal coun terexample to the belief that all 4D TQFTs are true gauge theories.\n LOCATION:https://researchseminars.org/talk/SymSem/15/ END:VEVENT BEGIN:VEVENT SUMMARY:Maissam Barkeshli (Maryland) DTSTART:20221011T140000Z DTEND:20221011T150000Z DTSTAMP:20260422T225702Z UID:SymSem/16 DESCRIPTION:Title: Defects and higher symmetries in (3+1)D topological phases of matter\n by Maissam Barkeshli (Maryland) as part of Symmetry Seminar\n\n\nAbstract\ n(3+1)D topological phases of matter can host interesting classes of non-t rivial topological defects of varying codimension\, of which the well-know n point charges and flux loops are special cases. The complete algebraic s tructure of these defects defines a higher category\, and can be viewed as an emergent higher symmetry. This plays an important role both in the cla ssification of phases of matter and the possible fault-tolerant logical op erations in quantum error correcting codes. In this talk I will discuss so me recent progress in our understanding of the properties of invertible de fects and higher group symmetries in (3+1)D topological phases of matter. Along the way I will review some progress over the past few years in chara cterizing topological phases of matter and their defects in low dimensions .\n LOCATION:https://researchseminars.org/talk/SymSem/16/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Ferrari (Durham) DTSTART:20221018T140000Z DTEND:20221018T150000Z DTSTAMP:20260422T225702Z UID:SymSem/17 DESCRIPTION:Title: Non-invertible Symmetries and Higher Representation Theory\nby Andrea Ferrari (Durham) as part of Symmetry Seminar\n\n\nAbstract\nThere has rece ntly been a lot of excitement surrounding non-invertible global symmetries and their potential applications. An important question is how to systema tically construct theories whose non-invertible symmetry categories we can control well. In this talk I will suggest that higher representation theo ry can help us to answer this question when the symmetries are non-intrins ically non-invertible. In particular\, I will explain how the topological defects obtained after gauging finite groups and 2-groups in 3 dimensions form the category of 2-representations of the original 2-group\, and how t his fact can be applied to some gauge theories with disconnected gauge gro ups. The same techniques can be extended to more general higher groups and subgroups in higher dimensions.\n LOCATION:https://researchseminars.org/talk/SymSem/17/ END:VEVENT BEGIN:VEVENT SUMMARY:David Reutter (Hamburg) DTSTART:20221101T150000Z DTEND:20221101T160000Z DTSTAMP:20260422T225702Z UID:SymSem/18 DESCRIPTION:Title: Higher fusion categories and their fusion rings\nby David Reutter (Ham burg) as part of Symmetry Seminar\n\n\nAbstract\nHigher fusion categories are certain algebraic gadgets which capture some of the behavior of topolo gical operators/defects in higher-dimensional quantum field theories. \n\n In the first part of this talk\, I will give an introduction to the basic concepts of higher fusion category theory and overview some key examples. If time permits\, I will then explain how every fusion n-category C has as sociated `homotopy sets' pi_k C\, defined as a certain quotient of the set of (k+1)-codimensional operators. I will sketch how these sets pi_k C car ry a kind of fusion ring structure and how in the modular case this fusion ring structure can be recovered from a higher-dimensional Verlinde formul a.\n\n \n\nThe first part of this talk is based on arXiv:1812.11933 (joint with Christopher Douglas)\, the second part is based on ongoing joint wor k with Theo Johnson-Freyd.\n LOCATION:https://researchseminars.org/talk/SymSem/18/ END:VEVENT BEGIN:VEVENT SUMMARY:Xiao-Gang Wen (MIT) DTSTART:20221108T150000Z DTEND:20221108T160000Z DTSTAMP:20260422T225702Z UID:SymSem/19 DESCRIPTION:Title: A classification of 3+1D topological orders and non-degenerate unitary bra ided fusion 2-category\nby Xiao-Gang Wen (MIT) as part of Symmetry Sem inar\n\n\nAbstract\nI will discuss the microscopic definition of topologic al orders in 3d space and its connection with non-degenerate unitary braid ed fusion 2-categories (or unitary fusion 3-categories with trivial center ). Then I will discuss a "physical" classification of 3+1D topological or ders (and non-degenerate unitary braided fusion 2-categories or unitary fu sion 3-categories with trivial center).\n LOCATION:https://researchseminars.org/talk/SymSem/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Fiona Burnell (Minnesota) DTSTART:20221025T140000Z DTEND:20221025T150000Z DTSTAMP:20260422T225702Z UID:SymSem/20 DESCRIPTION:Title: Subsystem symmetry protected phases and anomalies in higher-form gauge the ories\nby Fiona Burnell (Minnesota) as part of Symmetry Seminar\n\n\nA bstract\nRecent interest in systems with excitations that have sub-dimensi onal mobility and conserved higher-multipole moments has motivated an inve stigation of models with so-called subsystem symmetry\, in which conservat ion laws apply not to the system as a whole\, but rather to sub manifolds within the system\, such as families of lattice planes. I will discuss ana logs of symmetry protection in these phases\, and its relation to anomalie s in the corresponding field theoretical description\, which involves tens or gauge fields.\n LOCATION:https://researchseminars.org/talk/SymSem/20/ END:VEVENT BEGIN:VEVENT SUMMARY:Javier Mangan (UPenn) DTSTART:20221115T150000Z DTEND:20221115T160000Z DTSTAMP:20260422T225702Z UID:SymSem/21 DESCRIPTION:Title: Generalized symmetries\, Noether and Weinberg-Witten\nby Javier Mangan (UPenn) as part of Symmetry Seminar\n\n\nAbstract\nIn this talk we descri be new theorems concerning the mixing of symmetries in QFT. In particular\ ,\nwe show that generalized symmetries cannot be charged under a continuou s global symmetry having a Noether\ncurrent. The results follow from a fin er classification of twist operators\, which naturally extends to\nfinite group global symmetries. They unravel topological obstructions to the stro ng version of Noether’s\ntheorem in QFT\, even if under general conditio ns a global symmetry can be implemented locally by twist\noperators (weak version). We use these results to rederive Weinberg-Witten’s theorem wit hin local QFT\,\ngeneralizing it in several directions. We end up discussi ng the conditions for the strong version to hold\,\ndynamical aspects of Q FT’s with non-compact generalized symmetries\, scale vs conformal invari ance in QFT\nand connections with the Coleman-Mandula theorem.\n LOCATION:https://researchseminars.org/talk/SymSem/21/ END:VEVENT BEGIN:VEVENT SUMMARY:Christian Copetti (SISSA) DTSTART:20221122T150000Z DTEND:20221122T160000Z DTSTAMP:20260422T225702Z UID:SymSem/22 DESCRIPTION:Title: Zoology of duality defects: the view from class S\nby Christian Copett i (SISSA) as part of Symmetry Seminar\n\n\nAbstract\nWe review known const ructions of non-invertible duality defects for general QFTs and explain th eir emergence in the context of theories of class S. This leads us to defi ning the of "rank" of a non-invertible symmetry. We explain to compute it and its impact the fusion algebra.\n\nBased on upcoming work with A. Antin ucci\, G. Galati and G. Rizi.\n LOCATION:https://researchseminars.org/talk/SymSem/22/ END:VEVENT BEGIN:VEVENT SUMMARY:Matthew Yu (Perimeter) DTSTART:20221206T150000Z DTEND:20221206T160000Z DTSTAMP:20260422T225702Z UID:SymSem/23 DESCRIPTION:Title: Gauging noninvertible surface operators\, and the 2-Deligne theorem.\n by Matthew Yu (Perimeter) as part of Symmetry Seminar\n\n\nAbstract\nI wil l explain a generalization of the notion of an anomaly for a symmetry to a noninvertible symmetry enacted by surface operators using the framework o f condensation in 2-categories. I will give examples of when we have reaso nable control over these anomalies\, and prove theorems about the structur e of the 2-category obtained by condensing a suitable algebra object. I w ill provide examples where the resulting category displays grouplike fusio n rules and through a cohomology computation\, find the obstruction to con densing further to the vacuum theory. I will then present the main result of this work\, which categorifies a theorem of Deligne about the existence of fibre functors for 1-categories. This work was done in collaboration with Thibault Decoppet.\n LOCATION:https://researchseminars.org/talk/SymSem/23/ END:VEVENT BEGIN:VEVENT SUMMARY:Fabio Apruzzi (Bern) DTSTART:20221129T150000Z DTEND:20221129T160000Z DTSTAMP:20260422T225702Z UID:SymSem/24 DESCRIPTION:Title: Non-invertible symmetries from holography and branes\nby Fabio Apruzzi (Bern) as part of Symmetry Seminar\n\n\nAbstract\nGeneralised non-inverti ble symmetries have emerged in past year as a new type of symmetry in d≥ 4 QFTs. This has lead to a new understanding of certain constraints on th e low-energy dynamics of QFTs\, such as QED\, or the standard model. In th is talk\, I will describe a systematic approach to deriving symmetry gener ators of Quantum Field Theories in holography. Central to this are the Gau ss law constraints in the Hamiltonian quantization of Symmetry Topological Field Theories (SymTFTs)\, which are obtained from supergravity. Cruciall y\, we realize the symmetry generators from world-volume theories of D-bra nes in holography. I will particularly focus on non-invertible symmetries\ , by presenting the application of our proposal in the holographic setup\, dual to 4d N=1 SU(M) or PSU(M) Super-Yang Mills (SYM). In the brane-pictu re\, the fusion of non-invertible symmetries naturally arises from the Mye rs effect on D-branes. In addition\, the action of the topological non-inv ertible defects t’Hooft on line is modelled by the Hanany-Witten effect. For SU and PSU SYM\, we also identify the infra-red (IR) 4d field theory from the dual gravity description\, which describes the domain-walls and c onfining/deconfining behaviour in the IR.\n LOCATION:https://researchseminars.org/talk/SymSem/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Lian Kong (SIQSE\, Southern University of Science and Technology) DTSTART:20230117T140000Z DTEND:20230117T150000Z DTSTAMP:20260422T225702Z UID:SymSem/25 DESCRIPTION:Title: Global Quantum Many-body Theory\nby Lian Kong (SIQSE\, Southern Univer sity of Science and Technology) as part of Symmetry Seminar\n\n\nAbstract\ nThe program of studying the categories of topological orders or quantum l iquids\, was initiated in 1502.01690 and 1702.00673\, where the notion of a morphism between two topological orders (or quantum liquids) was introdu ced. This notion is different from the usual definition by a domain wall b ut contains the recent idea of Symmetry TFT as special cases. In this talk \, I will review this notion and show how it led us immediately to the so- called boundary-bulk relation\, then to a unified theory of both gapped an d gapless boundaries of 2+1D topological orders and topological Wick rotat ion 1705.01087\,1905.04924\,1912.01760\, and eventually to a mathematical theory of gapped/gapless quantum liquids 2011.02859\, 2107.03858\, 2201.05 726\n LOCATION:https://researchseminars.org/talk/SymSem/25/ END:VEVENT BEGIN:VEVENT SUMMARY:Nathan Seiberg (IAS) DTSTART:20230124T150000Z DTEND:20230124T160000Z DTSTAMP:20260422T225702Z UID:SymSem/26 DESCRIPTION:Title: Symmetries and Anomalies in the Continuum and on the Lattice\nby Natha n Seiberg (IAS) as part of Symmetry Seminar\n\n\nAbstract\nBased on joint work with Meng Cheng (arXiv:2211.12543)\, we will discuss some aspects of global symmetries and their ‘t Hooft anomalies.\nWe will define a notion of an emanant global symmetry. It is not a symmetry of the UV theory\, b ut unlike emergent (accidental) symmetries\, it is not violated by any rel evant or irrelevant operators in the IR theory. \nWe will present lattice models with anomalous internal symmetries and see how the anomalies are di agnosed on the lattice using topological defects.\nWe will also discuss la ttice models with anomalous lattice translation and relate them to an anom alous emanant symmetry in the IR theory. This will connect our discussion to the well-known Lieb-Schultz-Mattis theorem and to filling constraints like Luttinger theorem.\n LOCATION:https://researchseminars.org/talk/SymSem/26/ END:VEVENT BEGIN:VEVENT SUMMARY:Clay Cordova (Chicago) DTSTART:20230214T150000Z DTEND:20230214T160000Z DTSTAMP:20260422T225702Z UID:SymSem/27 DESCRIPTION:Title: Neutrino Masses from Generalized Symmetry Breaking\nby Clay Cordova (C hicago) as part of Symmetry Seminar\n\n\nAbstract\nWe explore generalized global symmetries in theories of physics Beyond the Standard Model. Models with Z' bosons generically contain `non-invertible' chiral symmetries\, w hose presence indicates a natural paradigm to break this symmetry by an ex ponentially small amount in an ultraviolet completion. For example\, in mo dels of gauged lepton family difference\, there is a non-invertible lepton number symmetry which protects neutrinomasses. We embed these theories in gauged non-Abelian horizontal lepton symmetries\, e.g SU(3)_H\, where th e generalized symmetries are broken non-perturbatively by the existence of lepton family magnetic monopoles. In such theories\, either Majorana or D irac neutrino masses may be generated through quantum gauge theory effects from the charged lepton Yukawas. These theories require no bevy of new fi elds nor ad hoc additional global symmetries\, but are instead simple\, na tural\, and predictive: the discovery of a lepton family Z' at low energie s will reveal the scale at which it emerges from a larger gauge symmetry.\ n LOCATION:https://researchseminars.org/talk/SymSem/27/ END:VEVENT BEGIN:VEVENT SUMMARY:Lakshya Bhardwaj (Oxford) DTSTART:20230131T150000Z DTEND:20230131T160000Z DTSTAMP:20260422T225702Z UID:SymSem/28 DESCRIPTION:Title: Non-Invertible Theta Symmetries\nby Lakshya Bhardwaj (Oxford) as part of Symmetry Seminar\n\n\nAbstract\nIt is by now well-known that the symmet ries of a d-dimensional quantum field theory form a fusion (d-1)-category. This contains a fusion 1-category piece formed by genuine topological lin e operators and non-genuine topological local operators which is extremely well understood both physically and mathematically. This talk will discus s recent physical and mathematical understandings of a fusion 2-category p iece formed by genuine topological surface operators and non-genuine topol ogical line & local operators\, which contains within it the above fusion 1-category piece. For simplest physical constructions\, the fusion 2-categ ory can be identified with the 2-category formed by 2-representations of a finite group G. We will discuss the mathematical definition of 2-represen tations and provide a simple universal physical reasoning for their appear ance: namely that any QFT that can be obtained by gauging a 0-form symmetr y group G contains dual non-invertible symmetries described by surface ope rators labeled by 2-representations of G. We refer to such universal symme tries as theta symmetries because they generalize the notion of theta angl e. We will then proceed to discuss the inclusion of non-universal symmetri es that depend on the specifics of the QFT under consideration. We will se e that the physical reasoning involved in the discussion of universal thet a symmetries will continue to play a major role also for non-universal sym metries\, leading to the notion of "twisted theta symmetries". Many intere sting physical phenomena like symmetry fractionalization on condensation d efects will be encountered. Towards the end of the talk\, we will briefly discuss the generalization of these studies to fusion 3-categories and hig her. This involves various physical and mathematical subtleties having to do with the fact that TQFTs in spacetime dimension bigger than two form an extremely rich mathematical structure.\n LOCATION:https://researchseminars.org/talk/SymSem/28/ END:VEVENT BEGIN:VEVENT SUMMARY:Emily Nardoni (Kavli IPMU) DTSTART:20230221T140000Z DTEND:20230221T150000Z DTSTAMP:20260422T225702Z UID:SymSem/29 DESCRIPTION:Title: Probing Anomalies of Non-Invertible Symmetries with Symmetry TFTs\nby Emily Nardoni (Kavli IPMU) as part of Symmetry Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/SymSem/29/ END:VEVENT BEGIN:VEVENT SUMMARY:Miguel Montero (Madrid) DTSTART:20230228T150000Z DTEND:20230228T160000Z DTSTAMP:20260422T225702Z UID:SymSem/30 DESCRIPTION:Title: The Chronicles of IIBordia\nby Miguel Montero (Madrid) as part of Symm etry Seminar\n\n\nAbstract\nWe will embark on a journey through the realms of cobordism groups in IIB string theory\, taking into account the dualit y symmetry of the theory. These cobordism groups are interesting because t hey can be used systematically to predict new generalized symmetries of II B supergravity and the corresponding objects that break them in IIB string theory. In this way we are able to recover many known branes and a few un known ones. We will describe some particularly interesting examples\, disc uss the connection to topological couplings and anomalies in IIB string th eory\, and time permitting\, I will comment on the likely fate of non-inve rtible symmetries in quantum gravity.\n LOCATION:https://researchseminars.org/talk/SymSem/30/ END:VEVENT BEGIN:VEVENT SUMMARY:Zohar Komargodski (SCGP) DTSTART:20230321T150000Z DTEND:20230321T160000Z DTSTAMP:20260422T225702Z UID:SymSem/31 DESCRIPTION:Title: Line Operators\, RG Flows\, and One-Form Symmetry\nby Zohar Komargodsk i (SCGP) as part of Symmetry Seminar\n\nAbstract: TBA\n LOCATION:https://researchseminars.org/talk/SymSem/31/ END:VEVENT BEGIN:VEVENT SUMMARY:Wenjie Ji (UCSB) DTSTART:20230328T140000Z DTEND:20230328T150000Z DTSTAMP:20260422T225702Z UID:SymSem/32 DESCRIPTION:Title: Recent progress in the symmetry/topological order correspondence\nby W enjie Ji (UCSB) as part of Symmetry Seminar\n\n\nAbstract\nIn this talk\, we discuss some recent progress in the symmetry/topological order correspo ndence. The correspondence basically says that topological aspects of a di screte symmetry in d dimensions are captured by topological data in a topo logical order in d+1 dimensions. The topological aspects of symmetry inclu de but are not limited to symmetry charges\, defects\, their fusion rules as well as commutation relations. We will discuss (1) how a beyond-Landau transition is solved using the correspondence (arXiv: 2205.06244) and (2) in practice how we derive a topological order for a given symmetry in a 1+ 1d conformal field theory (arXiv:2106.02069). For the latter\, two cases a re particularly interesting: (i) when the symmetry is anomalous\, (ii) aft er the CFT is matched with a topological order\, there is a further symmet ry that enriches the topological order. If time allowed\, we discuss the s imilarities and relations of our setting with that proposed by Freed\, Moo re\, and Teleman.\n LOCATION:https://researchseminars.org/talk/SymSem/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Daniel Brennan (UCSD) DTSTART:20230404T140000Z DTEND:20230404T150000Z DTSTAMP:20260422T225702Z UID:SymSem/33 DESCRIPTION:Title: Coupling a Cosmic String to a TQFT\nby Daniel Brennan (UCSD) as part o f Symmetry Seminar\n\n\nAbstract\nIn this talk we will study a model that couples axion-Maxwell theory to a TQFT. Here\, we will show that there are phenomenological consequences of this coupling and leave potentially meas urable effects from the cosmological evolution of our universe.\n LOCATION:https://researchseminars.org/talk/SymSem/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Pavel Putrov (ICTP) DTSTART:20230411T140000Z DTEND:20230411T150000Z DTSTAMP:20260422T225702Z UID:SymSem/34 DESCRIPTION:Title: Non-invertible symmetries and mixed gravitational anomalies\nby Pavel Putrov (ICTP) as part of Symmetry Seminar\n\n\nAbstract\nIn my talk I will describe how a presence of a mixed anomaly between a global symmetry and gravity can be traded off for non-invertibility of the charge operators. S pecifically\, I will consider the cases of U(1) and Z4 symmetries (which i nclude fermion parity) in 4d. I will also comment on the relevance for the Standard Model. The talk is based on a joint work with Juven Wang.\n LOCATION:https://researchseminars.org/talk/SymSem/34/ END:VEVENT BEGIN:VEVENT SUMMARY:Ruben Verresen (Harvard) DTSTART:20230509T140000Z DTEND:20230509T150000Z DTSTAMP:20260422T225702Z UID:SymSem/35 DESCRIPTION:Title: Higgs condensates are symmetry-protected topological phases: from cluster states to superconductors\nby Ruben Verresen (Harvard) as part of Symm etry Seminar\n\n\nAbstract\nDeconfined phases of gauge theories are now we ll-understood as spontaneously breaking higher-form symmetries. How does t he Higgs phase fit in this way of thinking? In this talk\, we will explore how the Higgs phase does not just preserve such a higher-form symmetry\, but is in a non-trivial symmetry-protected topological (SPT) phase. This s heds new light on the distinction between confined and Higgs phases. In fa ct\, the remarkable properties of superconductors---which are Higgs phases for U(1) gauge theory---can be derived as SPT properties! This is based o n the works arxiv:2010.00607\, arxiv:2211.01376 and arxiv:2303.08136.\n LOCATION:https://researchseminars.org/talk/SymSem/35/ END:VEVENT BEGIN:VEVENT SUMMARY:Clement Delcamp (Ghent) DTSTART:20230516T140000Z DTEND:20230516T150000Z DTSTAMP:20260422T225702Z UID:SymSem/36 DESCRIPTION:Title: Higher categorical symmetries and gauging on the lattice\nby Clement D elcamp (Ghent) as part of Symmetry Seminar\n\n\nAbstract\nHigher categoric al symmetries have received widespread attention in recent years. Though e xotic\, such generalised symmetries have been shown to naturally arise as dual symmetries upon gauging invertible symmetries. Given an arbitrary two -dimensional lattice model with an ordinary symmetry\, I will present an a pproach to perform the (twisted) gauging of any of its sub-symmetries and study the resulting symmetry structure. Specialising to certain finite gro up generalisations of the (2+1)d transverse-field Ising model\, I will exp licitly construct lattice symmetry operators organised into fusion 2-categ ories of higher representations of higher groups.\n LOCATION:https://researchseminars.org/talk/SymSem/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Gregory Moore (Rutgers) DTSTART:20230523T140000Z DTEND:20230523T150000Z DTSTAMP:20260422T225702Z UID:SymSem/37 DESCRIPTION:Title: Finite Symmetries Of Field Theories From TQFT\nby Gregory Moore (Rutge rs) as part of Symmetry Seminar\n\n\nAbstract\nI will review some aspects of the paper ``Topological Field Theory In Quantum Field Theory\,'' writte n with Dan Freed and Constantin Teleman. I will review some aspects of fin ite homotopy theories\, which form the main source of examples in the pape r\, and attempt to give a talk complementary to the several excellent talk s by Freed and Teleman already available online.\n LOCATION:https://researchseminars.org/talk/SymSem/37/ END:VEVENT BEGIN:VEVENT SUMMARY:Simone Giacomelli (Milano) DTSTART:20230502T140000Z DTEND:20230502T150000Z DTSTAMP:20260422T225702Z UID:SymSem/38 DESCRIPTION:Title: Comments on Non-invertible Symmetries in Argyres-Douglas Theories\nby Simone Giacomelli (Milano) as part of Symmetry Seminar\n\n\nAbstract\nIn t his seminar I discuss the presence of non-invertible symmetries in an infi nite family of superconformal Argyres-Douglas theories. This class of theo ries arises from diagonal gauging of the flavor symmetry of a collection o f multiple copies of D_p(SU(N)) theories. The same set of theories that we study can also be realized from 6d N=(1\,0) compactification on a torus. The main example in this class is the (A_2\, D_4) theory\, which bears the same structures of non-invertible duality and triality defects as those o f N=4 super Yang-Mills with gauge algebra su(2). This result extends to in finitely many other Argyres-Douglas theories in the same family\, includin g those with central charges a=c whose conformal manifold is one dimension al\, and those with a\\neq c whose conformal manifold has dimension larger than one. This conclusion is supported by examining certain special cases that can be realized in terms of theories of class S.\n LOCATION:https://researchseminars.org/talk/SymSem/38/ END:VEVENT BEGIN:VEVENT SUMMARY:Andrea Antinucci (Sissa) DTSTART:20230919T140000Z DTEND:20230919T150000Z DTSTAMP:20260422T225702Z UID:SymSem/39 DESCRIPTION:Title: Anomalies of non-invertible self-duality symmetries: fractionalization and gauging"\nby Andrea Antinucci (Sissa) as part of Symmetry Seminar\n\n \nAbstract\nAnomalies of global symmetries are important tools for constra ining the dynamics of QFTs\, hence their generalization to non-invertible symmetries is clearly important. Their definition and classification\, how ever\, are still puzzling. In this talk\, I will argue that defining anoma lies as obstructions to gauging makes them computable using symmetry topol ogical field theory (SymmTFT). I will focus on duality defects\, arising i n d=2n dimensional theories self-dual under gauging a finite abelian n-1 f orm symmetry. For d=2\, the classification of anomalies was already known in the mathematical literature\, and I will demonstrate how to reproduce t hese results with techniques easily generalizable to higher dimensions. In any dimension\, we find two obstructions to gauging. The first indicates that intrinsically non-invertible symmetries are always anomalous. When th is obstruction vanishes\, a second one can emerge\, linked to a pure anoma ly in the global variant where the duality defect is invertible. Calculati ng this requires extra data\, which I will argue corresponds to a choice o f symmetry fractionalization. Based on joint work (2308.11707) with F. Ben ini\, C. Copetti\, G. Galati\, G. Rizi.\n LOCATION:https://researchseminars.org/talk/SymSem/39/ END:VEVENT BEGIN:VEVENT SUMMARY:Sal Pace (MIT) DTSTART:20230926T140000Z DTEND:20230926T150000Z DTSTAMP:20260422T225702Z UID:SymSem/40 DESCRIPTION:Title: Emergent generalized symmetries in ordered phases and their spontaneous br eaking.\nby Sal Pace (MIT) as part of Symmetry Seminar\n\n\nAbstract\n Based on recent work (arXiv:2308.05730) and upcoming work with Chenchang Z hu\, Agnès Beaudry\, and Xiao-Gang Wen\, we will discuss (non-)invertible higher-form symmetries that emerge in generic ordered phases and their ph ysical consequences. Such phases arise from spontaneously breaking an ordi nary symmetry G down to a subgroup H\, are described in the deep IR by a n onlinear sigma model with target space G/H\, and are ubiquitous to condens ed matter and high energy physics. We will focus on two aspects of this st ory: (1) when the generalized symmetry is finite\, the fusion higher categ ory describing its symmetry defects\, and (2) its spontaneous breaking\, w hich drives a phase transition to a nontrivial disordered phase with (non- )abelian topological orders and emergent photons. We will present examples for different groups G and H and construct lattice and continuum models t hat realize the generalized symmetry's spontaneous symmetry-breaking phase s.\n LOCATION:https://researchseminars.org/talk/SymSem/40/ END:VEVENT BEGIN:VEVENT SUMMARY:Kantaro Ohmori (Tokyo) DTSTART:20231024T130000Z DTEND:20231024T140000Z DTSTAMP:20260422T225702Z UID:SymSem/41 DESCRIPTION:Title: Non-supersymmetric Heterotic Branes\nby Kantaro Ohmori (Tokyo) as part of Symmetry Seminar\n\n\nAbstract\nThe completeness conjecture states tha t a consistent quantum gravity theory contains dynamical objects bearing a ll conceivable charges. McNamara and Vafa proposed that such charges can b e classified by bordism classes in the operational EFT\, which indicates t hat there may be several yet-to-be-identified branes within string theory. In this talk\, I will elucidate some of these charges as they pertain to heterotic string theories and subsequently explore potential worldsheet de scriptions of strings proximate to the corresponding branes.\n LOCATION:https://researchseminars.org/talk/SymSem/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Meng Cheng (Yale) DTSTART:20231031T150000Z DTEND:20231031T160000Z DTSTAMP:20260422T225702Z UID:SymSem/42 DESCRIPTION:Title: A defective look at quantum phases of matter\nby Meng Cheng (Yale) as part of Symmetry Seminar\n\n\nAbstract\nI will discuss recent developments in the classification and characterization of phases of matter in quantum many-body systems\, through the lens of topological defects of global sym metry. In the first part\, I will review how gapped phases with spatial sy mmetries can be understood using networks of background defects\, and appl y the construction to derive topological boundary states of (4+1)d "beyond -cohomology" SPT phases. The second part will discuss topological phases i n condensed matter systems with quenched disorder. Viewing disordered phas es as ensembles of defects\, I will describe a classification scheme of di sordered topological phases with exact and average symmetries.\n LOCATION:https://researchseminars.org/talk/SymSem/42/ END:VEVENT BEGIN:VEVENT SUMMARY:Marieke van Beest (SCGP) DTSTART:20231003T140000Z DTEND:20231003T150000Z DTSTAMP:20260422T225702Z UID:SymSem/43 DESCRIPTION:Title: Monopoles\, Scattering\, and Generalized Symmetries\nby Marieke van Be est (SCGP) as part of Symmetry Seminar\n\n\nAbstract\nI will discuss the p roblem of electrically charged\, massless fermions scattering off magnetic monopoles. The interpretation of the outgoing states has long been a puzz le\, as they can carry fractional quantum numbers. We argue that such outg oing particles live in the twisted sector of a topological co-dimension 1 surface\, which ends topologically on the monopole. This surface is in gen eral noninvertible\, and as such the outgoing radiation not only carries u nconventional flavor quantum numbers\, but is trailed by a topological fie ld theory\, which is a new prediction.\n LOCATION:https://researchseminars.org/talk/SymSem/43/ END:VEVENT BEGIN:VEVENT SUMMARY:Kansei Inamura (Tokyo) DTSTART:20231017T140000Z DTEND:20231017T150000Z DTSTAMP:20260422T225702Z UID:SymSem/44 DESCRIPTION:Title: Fusion surface models: 2+1d lattice models from fusion 2-categories\nb y Kansei Inamura (Tokyo) as part of Symmetry Seminar\n\n\nAbstract\nWe wil l discuss a systematic way to construct (2+1)-dimensional lattice models w ith finite generalized symmetries described by fusion 2-categories. These models are 2+1d analogues of the 1+1d anyon chain models and are dubbed fu sion surface models. We will also see that our models naturally arise from 4d topological field theories put on a slab. Examples of fusion 2-categor ies include modular tensor 1-categories that describe the symmetries gener ated by anyons. Thus\, the fusion surface models with such symmetries may provide natural candidates for chiral topological phases on the lattice.\n LOCATION:https://researchseminars.org/talk/SymSem/44/ END:VEVENT BEGIN:VEVENT SUMMARY:Shu-Heng Shao (Stony Broook) DTSTART:20231010T140000Z DTEND:20231010T150000Z DTSTAMP:20260422T225702Z UID:SymSem/45 DESCRIPTION:Title: Non-invertible lattice translation\nby Shu-Heng Shao (Stony Broook) as part of Symmetry Seminar\n\n\nAbstract\nI will discuss non-invertible sym metries in 1+1d lattice models with a tensor-product Hilbert space\, inclu ding the transverse-field Ising model and its deformation. The Kramers-Wan nier duality operator on the lattice mixes with the lattice translation\, and obeys a different non-invertible algebra compared to the continuum one .\n LOCATION:https://researchseminars.org/talk/SymSem/45/ END:VEVENT BEGIN:VEVENT SUMMARY:Ryan Thorngren (UCLA) DTSTART:20231107T170000Z DTEND:20231107T180000Z DTSTAMP:20260422T225702Z UID:SymSem/46 DESCRIPTION:Title: NOTE UNUSUAL TIME: The Symmetry Breaking Long Exact Sequence\nby Ryan Thorngren (UCLA) as part of Symmetry Seminar\n\n\nAbstract\nFractional or anomalous degrees of freedom at domain walls and vortices have been an imp ortant topic in physics for 50 years. In this talk\, we will look at these localized modes from a new point of view\, and study the matching problem between them and the gapped bulk modes. We will touch on recent ideas lik e higher Berry phase and discuss an interacting version of the Callias ind ex theorem. The talk is based on the work of my wonderful collaborators\, Arun Debray\, Sanath K. Devalapurkar\, Cameron Krulewski\, Yu Leon Liu\, a nd Natalia Pacheco-Tallaj\, which you can find here https://arxiv.org/abs/ 2309.16749 .\n LOCATION:https://researchseminars.org/talk/SymSem/46/ END:VEVENT BEGIN:VEVENT SUMMARY:Rajath Radhakrishnan (ICTP Trieste) DTSTART:20231121T150000Z DTEND:20231121T160000Z DTSTAMP:20260422T225702Z UID:SymSem/47 DESCRIPTION:Title: Constraints on non-invertible symmetries in 2+1D\nby Rajath Radhakrish nan (ICTP Trieste) as part of Symmetry Seminar\n\n\nAbstract\nIn this talk \, I will discuss some constraints on non-invertible symmetries implemente d by surface operators in 2+1D QFTs. I will first consider abelian TQFTs a nd argue that non-invertible surface operators exist if and only if there are bosonic line operators. I will then discuss an extension of this resul t to non-abelian TQFTs. This implies that all condensation defects are inv ertible in a TQFT without bosonic line operators. I will give an independe nt argument for this result using higher-gauging of line operators. Finall y\, I will discuss some implications for general 2+1D QFTs. This talk is b ased on the paper https://arxiv.org/abs/2309.15181 with Matthew Buican.\n LOCATION:https://researchseminars.org/talk/SymSem/47/ END:VEVENT BEGIN:VEVENT SUMMARY:Xie Chen (Caltech) DTSTART:20231128T150000Z DTEND:20231128T160000Z DTSTAMP:20260422T225702Z UID:SymSem/48 DESCRIPTION:Title: Sequential circuit as string operator for topological defects\nby Xie Chen (Caltech) as part of Symmetry Seminar\n\n\nAbstract\nBosonic point ch arge excitations in 3+1D topological phases can condense along a line and form a descendant defect called the Cheshire string. Unlike the elementary flux loop excitations in the system\, Cheshire strings do not have to app ear as the boundary of a 2D disc and can exist on open-line segments. On t he other hand\, Cheshire strings are different from trivial excitations th at can be created with either local unitaries in 0d or finite depth quantu m circuits in 1d and higher. In this talk\, we show that to create a Chesh ire string\, one needs the Sequential Quantum Circuit -- a linear depth ci rcuit that acts sequentially along the length of the string. Once a Cheshi re string is created\, its deformation\, movement\, and fusion can be real ized by finite depths circuits. Quantum circuits hence provide a way to de fine equivalence classes of gapped topological defects\, giving rise to a n operational meaning of the higher category description of topological or ders in 3+1D or higher.\n LOCATION:https://researchseminars.org/talk/SymSem/48/ END:VEVENT BEGIN:VEVENT SUMMARY:No Symmetry Seminar DTSTART:20231114T150000Z DTEND:20231114T160000Z DTSTAMP:20260422T225702Z UID:SymSem/49 DESCRIPTION:by No Symmetry Seminar as part of Symmetry Seminar\n\nAbstract : TBA\n LOCATION:https://researchseminars.org/talk/SymSem/49/ END:VEVENT BEGIN:VEVENT SUMMARY:Ryohei Kobayashi (Maryland) DTSTART:20231205T150000Z DTEND:20231205T160000Z DTSTAMP:20260422T225702Z UID:SymSem/50 DESCRIPTION:Title: Higher-group symmetry of (3+1)D Z2 gauge theory and non-Clifford logical g ates of toric codes\nby Ryohei Kobayashi (Maryland) as part of Symmetr y Seminar\n\n\nAbstract\nIt has recently been understood that the complete global symmetry of topological gauge theories contains the structure of a higher-group. In this talk\, we look at the higher-group structure of sym metry in (3+1)D Z2 gauge theory with an emergent fermion\, and point out t hat pumping chiral p+ip topological states gives rise to a Z8 0-form symme try with mixed gravitational anomaly. This ordinary symmetry mixes with th e other higher symmetries to form a 3-group structure\, which we discuss i n detail. \nWe then see that in the context of stabilizer quantum codes\, one can obtain various logical non-Clifford gates of (3+1)D Z2 toric code (w/ emergent fermion) including the CCZ\, CS and T gates\, which are all i mplemented by pumping a p+ip topological state through a 3d space.\nThe ta lk is mainly based on a recent work with Maissam Barkeshli and Po-Shen Hsi n\, which is found in https://arxiv.org/abs/2311.05674 .\n LOCATION:https://researchseminars.org/talk/SymSem/50/ END:VEVENT BEGIN:VEVENT SUMMARY:Nat Tantivasadakarn (Caltech) DTSTART:20240116T150000Z DTEND:20240116T160000Z DTSTAMP:20260422T225702Z UID:SymSem/51 DESCRIPTION:Title: Non-invertible SPT order in a group-based cluster state\nby Nat Tantiv asadakarn (Caltech) as part of Symmetry Seminar\n\n\nAbstract\nThe one-dim ensional cluster state is a paradigmatic example of a symmetry-protected t opological (SPT) state protected by Z2xZ2 symmetry in 1+1D. I will show th at a generalization of the cluster state to finite groups is an example of an SPT state protected by a non-invertible GxRep(G) symmetry\, belonging to a distinct phase from the symmetric product state. In this example\, th e signatures of SPT phases: protected edge modes\, string order parameters \, and topological response can be naturally generalized. Along the way\, I will highlight the deep relation between the cluster state and gauging ( the Kramers-Wannier transformation)\, the generalization of the Pauli matr ices from the group Z2 to finite groups\, and the power of tensor networks to express microscopic realizations of non-invertible symmetries. This ta lk is based on arXiv:2312.09272\n LOCATION:https://researchseminars.org/talk/SymSem/51/ END:VEVENT BEGIN:VEVENT SUMMARY:Riccardo Argurio (Brussels) DTSTART:20240130T150000Z DTEND:20240130T160000Z DTSTAMP:20260422T225702Z UID:SymSem/52 DESCRIPTION:Title: Spontaneous non-invertible symmetry breaking\nby Riccardo Argurio (Bru ssels) as part of Symmetry Seminar\n\n\nAbstract\nGiving (almost) for gran ted the motivation for generalized symmetries\, and spontaneous symmetry b reaking\, we focus on the latter phenomenon for non-invertible symmetries. These can be further distinguished in discrete\, rational and continuous\ , each case leading to different physics upon breaking. We first review th e case of discrete axial/R-symmetry\, analyzing both supersymmetric and no n-supersymmetric cases. We then consider the case of duality and triality symmetries\, and how they can be broken at the end of an RG flow. We final ly consider the peculiar case of continuous non-invertible Nambu-Goldstone bosons\, that parametrize an orbifold. The talk is based on results from https://arxiv.org/abs/2305.17084\, https://arxiv.org/abs/2306.01414\, http s://arxiv.org/abs/2309.06491.\n LOCATION:https://researchseminars.org/talk/SymSem/52/ END:VEVENT BEGIN:VEVENT SUMMARY:Giovanni Rizi (SISSA) DTSTART:20240123T150000Z DTEND:20240123T160000Z DTSTAMP:20260422T225702Z UID:SymSem/53 DESCRIPTION:Title: Non-Invertible Symmetries in Calabi-Yau Conformal Field Theories\nby G iovanni Rizi (SISSA) as part of Symmetry Seminar\n\n\nAbstract\nI will dis cuss non-invertible symmetries arising in 2d superconformal field theories corresponding to Calabi-Yau non linear sigma models. Our approach begins from a particularly symmetric point in the conformal manifold of the theor y\, the Gepner point. Here we are able to study in detail the supersymmetr ic topological defect lines and show that many exactly marginal deformatio ns preserve a subcategory of the symmetry at the Gepner point. This constr uction provides examples of continuous families of irrational (and interac ting) CFTs with non-invertible symmetries. Finally I will discuss some of the constraints those symmetries imply on correlation functions.\n\nBased on 2312.17308 with Clay Córdova.\n LOCATION:https://researchseminars.org/talk/SymSem/53/ END:VEVENT BEGIN:VEVENT SUMMARY:Lea Bottini (Oxford) DTSTART:20240206T150000Z DTEND:20240206T160000Z DTSTAMP:20260422T225702Z UID:SymSem/54 DESCRIPTION:Title: Gapped phases and phase transitions from the SymTFT\nby Lea Bottini (O xford) as part of Symmetry Seminar\n\n\nAbstract\nThe symmetry topological field theory (SymTFT) has emerged in the past years as a key tool to stud y generalized symmetries. In this talk\, I will explain how we can use it to determine gapped infra-red phases of 2d theories that have a symmetry S \, which in general is non-invertibile. Moreover\, I will introduce a gene ralization of the usual SymTFT framework that is useful to characterize ph ase transitions between such gapped phases. The SymTFT also manifestly enc odes the order parameters for the phases\, thus providing a generalized ve rsion of the Landau paradigm for categorical symmetries.\n LOCATION:https://researchseminars.org/talk/SymSem/54/ END:VEVENT BEGIN:VEVENT SUMMARY:Zhengdi Sun (UCLA) DTSTART:20240213T150000Z DTEND:20240213T160000Z DTSTAMP:20260422T225702Z UID:SymSem/55 DESCRIPTION:Title: Self-duality under gauging non-invertible symmetries in 2d CFT\nby Zhe ngdi Sun (UCLA) as part of Symmetry Seminar\n\n\nAbstract\nIt is well-know n that a QFT which is self-dual under gauging invertible symmetries generi cally admits a non-invertible duality defect (e.g. Kramers-Wannier duality defect in 2d Ising CFT). In this talk\, we will discuss the self-duality under gauging non-invertible symmetries in 2d CFT based on the work [arXiv :2310.19867]. We will first use the symmetry $Rep(H_8)$ as an example to d emonstrate how to gauge non-invertible symmetries in 2d CFT\, and then rep ort some examples of self-duality under gauging $Rep(H_8)$. Finally\, we d escribe the fusion categories containing the new duality defect arising fr om the self-duality under gauging $Rep(H_8)$.\n LOCATION:https://researchseminars.org/talk/SymSem/55/ END:VEVENT BEGIN:VEVENT SUMMARY:Max Hubner (UPenn) DTSTART:20240220T150000Z DTEND:20240220T160000Z DTSTAMP:20260422T225702Z UID:SymSem/56 DESCRIPTION:Title: On the Holographic Dual of a Topological Symmetry Operator\nby Max Hub ner (UPenn) as part of Symmetry Seminar\n\n\nAbstract\nIn the context of t he AdS/CFT correspondence\, we study the holographic dual of a topological symmetry operator. We argue that the bulk counterpart of such an operator has a non-topological worldvolume action\, i.e.\, it describes a dynamica l object. Our argument will be bottom up\, without reference to a top down construction\, and rely on smearing properties of entanglement wedge reco nstruction and holographic RG flows. Further\, we will compare to earlier work by Harlow and Ooguri on the absence of global symmetries in asymptoti cally AdS spacetimes. Finally\, we comment on stringy versions of various results. This talk is based on joint work with J. J. Heckman and C. Murdia .\n LOCATION:https://researchseminars.org/talk/SymSem/56/ END:VEVENT BEGIN:VEVENT SUMMARY:Lukasz Fidkowski (Seattle) DTSTART:20240227T150000Z DTEND:20240227T160000Z DTSTAMP:20260422T225702Z UID:SymSem/57 DESCRIPTION:Title: Quantum cellular automata and quantum phases of matter\nby Lukasz Fidk owski (Seattle) as part of Symmetry Seminar\n\n\nAbstract\nWe will show ho w quantum cellular automata (QCA)\, which originated in quantum informatio n theory\, appear naturally in the study of symmetry protected topological (SPT) phases of matter. Specifically\, they appear when one studies thes e phases in the "condensed matter" or "many-qubit model" context\, i.e. in a Hamiltonian formalism with a tensor product Hilbert space of finite dim ensional site Hilbert spaces. We will connect these ideas to continuum fi eld theory notions\, and will endeavor to make the talk accessible to high energy and low energy theorists alike.\n LOCATION:https://researchseminars.org/talk/SymSem/57/ END:VEVENT BEGIN:VEVENT SUMMARY:Matt Reece (Harvard) DTSTART:20240305T150000Z DTEND:20240305T160000Z DTSTAMP:20260422T225702Z UID:SymSem/58 DESCRIPTION:Title: Instanton Number as a Symmetry\nby Matt Reece (Harvard) as part of Sym metry Seminar\n\n\nAbstract\nGauge theories in d dimensions have a (d-5)-f orm generalized global symmetry whose conserved charge is instanton number . In quantum gravity\, we expect such symmetries to always be gauged or ex plicitly broken. I will discuss examples of how both can happen: gauging v ia Chern-Simons terms or (in 4d) massless fermions\, and explicit breaking via magnetic monopoles (in both abelian and nonabelian gauge theories). I n the case d=4\, instanton number symmetry is a “(-1)-form U(1) symmetry \,” a somewhat degenerate case. I will discuss several closely analogous properties of the cases d=4 and d>4\, to argue that we should take the no tion of (-1)-form symmetry seriously. I will comment on some implications of this perspective for the Strong CP problem. This talk will draw on mult iple papers\, including https://arxiv.org/abs/2012.00009 with Ben Heidenre ich\, Jake McNamara\, Miguel Montero\, Tom Rudelius\, and Irene Valenzuela \; https://arxiv.org/abs/2105.09950 with JiJi Fan\, Katie Fraser\, and Joh n Stout\; https://arxiv.org/abs/2402.00117 with Daniel Aloni\, Eduardo Gar cía-Valdecasas\, and Motoo Suzuki\; and other work in progress.\n LOCATION:https://researchseminars.org/talk/SymSem/58/ END:VEVENT BEGIN:VEVENT SUMMARY:Chong Wang (PI) DTSTART:20240312T150000Z DTEND:20240312T160000Z DTSTAMP:20260422T225702Z UID:SymSem/59 DESCRIPTION:Title: Mixed-state quantum anomaly and multipartite entanglement\nby Chong Wa ng (PI) as part of Symmetry Seminar\n\n\nAbstract\nQuantum entanglement me asures of many-body states have been increasingly useful to characterize p hases of matter. In this talk I will explore a surprising connection betwe en mixed state entanglement and 't Hooft anomaly. More specifically\, we c onsider lattice systems in d space dimensions with anomalous symmetry G wh ere the anomaly is characterized by an invariant in group cohomology. We s how that any mixed state ρ that is strongly symmetric under G\, in the se nse that Gρ~ρ\, is necessarily (d+2)-nonseparable\, i.e. is not the mixt ure of tensor products of (d+2) states in the Hilbert space. Furthermore\, such states cannot be prepared from any (d+2)-separable states using fini te-depth local quantum channels\, so the nonseparability is long-ranged in nature. We provide proof of these results in d<2\, and plausibility argum ents in higher dimensions. The anomaly-nonseparability connection thus al lows us to generate simple examples of mixed states with nontrivial long-r anged multipartite entanglement\, even in d=1.\n LOCATION:https://researchseminars.org/talk/SymSem/59/ END:VEVENT BEGIN:VEVENT SUMMARY:Shota Komatsu (CERN) DTSTART:20240326T150000Z DTEND:20240326T160000Z DTSTAMP:20260422T225702Z UID:SymSem/60 DESCRIPTION:Title: Non-Invertible Symmetries\, Anomalies and Scattering Amplitudes\nby Sh ota Komatsu (CERN) as part of Symmetry Seminar\n\n\nAbstract\nWe show that crossing symmetry of S-matrices is modified in certain theories with non- invertible symmetries or anomalies. Focusing on integrable flows to gapped phases in two dimensions\, we find that S-matrices derived previously fro m the bootstrap approach are incompatible with non-invertible symmetries a long the flow. We present consistent alternatives\, which however violate standard crossing symmetry and obey modified rules dictated by fusion cate gories. We extend these rules to theories with discrete anomalies.\n LOCATION:https://researchseminars.org/talk/SymSem/60/ END:VEVENT BEGIN:VEVENT SUMMARY:Sahand Seifnashri (IAS) DTSTART:20240416T140000Z DTEND:20240416T150000Z DTSTAMP:20260422T225702Z UID:SymSem/61 DESCRIPTION:Title: Cluster state as a non-invertible SPT phase\nby Sahand Seifnashri (IAS ) as part of Symmetry Seminar\n\n\nAbstract\nWe study the simplest lattice realizations of SPT phases protected by non-invertible symmetries. We sho w that the well-known 1+1d cluster model has a Rep(D8) non-invertible symm etry\, thereby identifying it as a non-invertible SPT phase. We also find commuting Pauli Hamiltonians for the remaining two Rep(D8) SPT phases\, ma tching the classification in field theory and mathematics. Finally\, we de termine the projective algebra and edge modes at the interfaces between th ese three non-invertible SPT phases.\n LOCATION:https://researchseminars.org/talk/SymSem/61/ END:VEVENT BEGIN:VEVENT SUMMARY:Jingxiang Wu (Oxford) DTSTART:20240430T140000Z DTEND:20240430T150000Z DTSTAMP:20260422T225702Z UID:SymSem/62 DESCRIPTION:Title: MTC[M3\, G]: 3d Topological Order Labeled by Seifert Manifolds\nby Jin gxiang Wu (Oxford) as part of Symmetry Seminar\n\n\nAbstract\nWe propose a correspondence between topological order in 2+1d\, i.e.\nmodular tensor c ategories (MTCs) and Seifert three-manifolds together\nwith a choice of AD E gauge group G. The correspondence defines for\nevery Seifert manifold a nd choice of G a fusion category\, which we\nconjecture to be modular when ever the Seifert manifold has trivial\nfirst homology group with coefficie nts in the center of G. The\nconstruction determines the spins of anyons and their S-matrix\, and\nprovides a constructive way to determine the R- and F-symbols from\nsimple building blocks. We explore the possibility tha t this\ncorrespondence provides an alternative classification of MTCs\, wh ich\nis put to the test by realizing all MTCs (unitary or non-unitary) wit h\nrank $r\\leq 5$ in terms of Seifert manifolds and a choice of Lie group \nG.\n LOCATION:https://researchseminars.org/talk/SymSem/62/ END:VEVENT BEGIN:VEVENT SUMMARY:Hao Zhang (IPMU) DTSTART:20240528T130000Z DTEND:20240528T140000Z DTSTAMP:20260422T225702Z UID:SymSem/63 DESCRIPTION:Title: K-theoretic Global Symmetry in String-constructed QFT and T-duality\nb y Hao Zhang (IPMU) as part of Symmetry Seminar\n\n\nAbstract\nWe propose t hat generalized symmetries in some string-constructed QFTs are given by tw isted K-theory\, so as to be manifestly consistent under T-duality. We thu s have even-form and odd-form symmetries determined by the twisted K-theor y as D-brane charges on the asymptotic boundary ∂X of internal geometry X with twist class N. For these QFTs\, "p-form symmetries" are no longer s eparately well-defined for individual p\, but instead mixed up. We discuss 6D ADE-type (2\,0) SCFTs and some 6d (1\,0) LSTs as examples\, and demons trate their twisted K-theoretic symmetries to be consistent with T-duality .\n LOCATION:https://researchseminars.org/talk/SymSem/63/ END:VEVENT BEGIN:VEVENT SUMMARY:Arkya Chatterjee (MIT) DTSTART:20240514T140000Z DTEND:20240514T150000Z DTSTAMP:20260422T225702Z UID:SymSem/64 DESCRIPTION:Title: Phases and Phase Transitions of Spin Chains with Non-invertible Symmetries \nby Arkya Chatterjee (MIT) as part of Symmetry Seminar\n\n\nAbstract\ nNon-invertible symmetries are often emergent at low-energies\nin gapless states of quantum matter. It is useful to construct lattice\nmodels that h ave these as exact symmetries in order to provide a\nUV-complete setting i n which they are well-controlled. To that end\, we\npropose to study one-d imensional Hamiltonians defined on tensor\nproduct Hilbert spaces with fin ite on-site dimension -- referred to as\n"spin chains" in short -- with ex act non-invertible symmetries. We\nfocus on two concrete examples: a spin chain with (invertible) S_3\nsymmetry and one with (non-invertible) Rep(S_ 3) symmetry. These models\nare largely analytically tractable and demonstr ate all spontaneous\nsymmetry breaking (SSB) phases of these symmetries. W ith the aid of\ntensor network algorithms\, we systematically study the ph ase\ntransitions between these SSB phases. Both models possess\n(intrinsic ally) non-invertible self-duality symmetries\, for which we\nprovide seque ntial circuit implementations. On the self-dual manifold\nin parameter spa ce\, we discover an incommensurate gapless phase with\nan anomalous U(1) s ymmetry which emanates from lattice translation.\n LOCATION:https://researchseminars.org/talk/SymSem/64/ END:VEVENT BEGIN:VEVENT SUMMARY:Xingyang Yu (Virginia Tech) DTSTART:20240521T150000Z DTEND:20240521T160000Z DTSTAMP:20260422T225702Z UID:SymSem/65 DESCRIPTION:Title: 2D Non-invertible Symmetries and Anomalies from String Theory\nby Xing yang Yu (Virginia Tech) as part of Symmetry Seminar\n\n\nAbstract\nWe inve stigate a string theory perspective for non-invertible symmetries in 2D QF Ts. In particular\, we discuss how symmetry topological field theories (Sy mTFTs) and anomalies of non-invertible symmetries arise from top down. Our primary focus is on an infinite class of 2D QFTs from Calabi-Yau 4-folds probed by D1-branes. We derive 3D SymTFTs from IIB string theory and show the resulting 2D QFTs can exhibit non-invertible symmetries with a wrapped brane origin. These non-invertible symmetries can suffer from anomalies\ , which are able to be translated into branes patterns ``at infinity''. Ex plicit examples are provided to illustrate our idea.\n LOCATION:https://researchseminars.org/talk/SymSem/65/ END:VEVENT BEGIN:VEVENT SUMMARY:Tyler Ellison (Yale) DTSTART:20240618T140000Z DTEND:20240618T150000Z DTSTAMP:20260422T225702Z UID:SymSem/66 DESCRIPTION:by Tyler Ellison (Yale) as part of Symmetry Seminar\n\nAbstrac t: TBA\n LOCATION:https://researchseminars.org/talk/SymSem/66/ END:VEVENT BEGIN:VEVENT SUMMARY:Apoorv Tiwari (NBI) DTSTART:20240625T140000Z DTEND:20240625T150000Z DTSTAMP:20260422T225702Z UID:SymSem/67 DESCRIPTION:Title: Fermionic Non-Invertible Symmetries in (1+1)d\nby Apoorv Tiwari (NBI) as part of Symmetry Seminar\n\n\nAbstract\nI will describe fermionic non-i nvertible symmetries in (1+1)d\, which are generalized global symmetries t hat mix fermion parity symmetry with other invertible and non-invertible i nternal symmetries. Mathematically\, such symmetries are described by fusi on π-supercategories with a choice of fermion parity. Using the formali sm of the Symmetry Topological Field Theory (SymTFT)\, I will present th e Landau paradigm for categorical  fermionic symmetries. This talk is b ased on arXiv:2405.09754\n LOCATION:https://researchseminars.org/talk/SymSem/67/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Gutperle (UCLA) DTSTART:20240709T140000Z DTEND:20240709T150000Z DTSTAMP:20260422T225702Z UID:SymSem/68 DESCRIPTION:Title: Non-invertible symmetries in S_N orbifold CFTs and holography\nby Mich ael Gutperle (UCLA) as part of Symmetry Seminar\n\n\nAbstract\nThis talk i s based on two recent papers (arxiv:2405.15693 and 2406.10967) by Y. Li\, D. Rathore\, K. Roumpedakis and M. Gutperle. We construct non-invertible defects in S_N symmetric orbifolds and discuss the spectrum of defect ope rators\, Ward-identities\, entanglement entropy in the presence of defects as well as a proposal for a world sheet dual of the topological defects i n the AdS/CFT dual of the symmetric orbifold.\n LOCATION:https://researchseminars.org/talk/SymSem/68/ END:VEVENT END:VCALENDAR