RIND Seminar on Mathematical Physics and String Theory

The RIND-Seminar (Rhein-Isar-Neckar-Donau) is a joint online video seminar series on theoretical and mathematical physics organized together by the JGU Mainz, the LMU Munich, the University of Heidelberg, and the University of Vienna via Zoom or BigBlueButton.

If you are interested in joining, please contact Mascha Ringe or one of the organizers for the Zoom or BigBlueButton credentials.

If you would like to join our mailing list for announcements and reminders, please contact Mascha Ringe or send an e-mail as follows to sympa@lists.uni-mainz.de and confirm by clicking the link in the e-mail you receive:

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Time: Mondays at 4:15 pm (UTC + 1)



Programm für das Wintersemester 2022/2023

Mondays, 16 Uhr c.t.

U. Mainz, LMU Munich, U. Heidelberg, U. Vienna

live at Zoom, BigBlueButton
24.10.22Albrecht Klemm, Bonn U.
Recently it has been realized that the parameter dependence of Feynman integrals in dimensional regularisation can be calculated explicitly using period-- and chain integrals of suitably chosen Calabi-Yau motives, where the transcendentality weight of the motive is proportional to the dimension of the Calabi Yau geometry and the loop order of the Feynman graphs. We exemplify this for the Banana graphs, the Ice Cone graphs and the Train Track graphs in two dimensions. In the latter case there is a calculational very useful relation between the differential realisation of the Yangian symmetries and the Picard-Fuchs system of compact Calabi-Yau spaces M as well as between the physical correlations functions and the quantum volume of the manifolds W that are the mirrors to M.
16 Uhr c.t., Munich, at Zoom

31.10.22Lorenz Eberhardt, IAS
I will revisit string one-loop amplitudes in this talk. After reviewing the basics, I will explain how Witten’s iepsilon prescription gives a manifestly convergent representation of the amplitude. I will then consider the imaginary part of the amplitude and show directly that it satisfies the standard field theory cutting rules. This leads to an exact representation of the imaginary part of the amplitude. I will also discuss physical properties of the imaginary part such as the singularity structure of the amplitude, its Regge and high energy fixed-angle behaviour and low-spin dominance. Finally, I will tease how Rademacher’s contour can be used to evaluate the full one-loop open string amplitude exactly in terms of a convergent infinite sum.
16 Uhr c.t., at Zoom

14.11.22Raghu Mahajan, Stanford U.
We use insights from string field theory to analyze and cure the divergences in the cylinder diagram in minimal string theory, with both boundaries lying on a ZZ brane. Minimal string theory refers to the theory of two-dimensional gravity coupled to a minimal model CFT that serves as the matter sector; it includes JT gravity as a limiting case. ZZ branes are akin to D-instantons, and give rise to features that reflect the underlying discreteness of the dual theory. The exponential of the cylinder diagram represents the one-loop determinant around the instanton saddle. The finite result for this one-loop constant computed using the string field theory procedure agrees precisely with independent calculations in the dual double-scaled matrix integrals performed by several authors many years ago.
16 Uhr c.t., at Zoom

28.11.22Enno Keßler, MPI-M Bonn
J-holomorphic curves or pseudoholomorphic curves are maps from Riemann surfaces to symplectic manifolds satisfying the Cauchy-Riemann equations. J-holomorphic curves are of great interest because they allow to construct invariants of symplectic manifolds and those invariants are deeply related to topological superstring theory. A crucial step towards Gromov–Witten invariants is the compactification of the moduli space of J-holomorphic curves via stable maps which was first proposed by Kontsevich and Manin. In this talk, I want to report on a supergeometric generalization of J- holomorphic curves and stable maps where the domain is a super Riemann surface. Super Riemann surfaces have first appeared as generalizations of Riemann surfaces with anti-commutative variables in superstring theory. Super J-holomorphic curves couple the equations of classical J-holomorphic curves with a Dirac equation for spinors and are critical points of the superconformal action. The compactification of the moduli space of super J- holomorphic curves via super stable maps might, in the future, lead to a supergeometric generalization of Gromov-Witten invariants. Based on arXiv:2010.15634 [math.DG] and arXiv:1911.05607 [math.DG], joint with Artan Sheshmani and Shing-Tung Yau.
16 Uhr c.t., at Zoom

05.12.22Nikita Nekrasov, Stony Brook U.
Calogero-Moser-Sutherland system of particles is a prototypical example of a system with fractional statistics. I review the old and new connections of this system to (super) Yang-Mills theory in various dimensions.
16 Uhr c.t., at Zoom

12.12.22Ida Zadeh, JGU Mainz
I will discuss compactification of the heterotic string on the smooth, flat 3-manifold T3/Z2, without supersymmetry. The low energy dynamics of the corresponding ten dimensional heterotic supergravity will be described. The semi-classical theory has both Coulomb and Higgs branches of non-supersymmetric vacua. An exact worldsheet description of the compactification will then be presented using the framework of asymmetric orbifolds of T3, where the orbifold generator involves a Nikulin non-symplectic involution of the even self-dual lattice of signature (19,3). This construction gives a novel conformal field theory description of the semi-classical field theory moduli space and reveals a rich pattern of transitions amongst Higgs and Coulomb branches.
16 Uhr c.t., at Zoom

19.12.22Niccolo Cribiori & Ralph Blumenhagen, Max Planck Institut for Physics, Munich
The absence of global symmetries is widely believed to be a principle of quantum gravity. Recently, it has been generalised to the statement that the cobordism group of quantum gravity must be trivial. Indeed, a non-trivial group detects a higher-form global symmetry, which has then to either be gauged or broken. In the case in which it is broken, defects have to be introduced into the setup. These can be end-of-the-world branes furnishing a dynamical realization of cobordism, of which we will provide a new concrete example. In the case in which the symmetry is gauged, we will argue that there is a non-trivial interplay between cobordism and K-theory, leading to the construction of type IIB/F-theory tadpoles from a bottom-up perspective. This interpretation of cobordism and K-theory as charges in quantum gravity can be given further support when passing from groups of the point to groups of a generic manifold X. We will argue that these more general groups have a natural interpretation in terms of the dimensional reduction of the theory on X. A systematic analysis can possibly lead to the prediction of new contributions to string theory tadpoles.
16 Uhr c.t., LMU Munich (Room A348), at Zoom

09.01.23Nicolo Piazzalunga, Uppsala U.
I'll introduce the higher-rank Donaldson-Thomas theory for toric Calabi-Yau three-folds, within the setting of equivariant K-theory. I'll present a factorization conjecture motivated by Physics. As a byproduct, I'll discuss some novel properties of equivariant volumes, as well as their generalizations to genus-zero Gromov-Witten theory of non-compact toric varieties.
16 Uhr c.t., Munich, at Zoom

30.01.23Konstantin Wernli, University of Southern Denmark
In the Batalin-Vilkovisky (BV) formalism, one can define a perturbative (i.e. given by Feynman graphs and rules) partition function $Z(x_0)$ for any choice of classical background (solution to Euler-Lagrange (EL) equations) $x_0$. In some examples one can extract from $Z$ a volume form on the smooth part of the moduli space of solutions to EL equations, and compare its integral with non-perturbative approaches to quantization. I will review this construction, some results from examples in the literature and ongoing joint work with P. Mnev about the behaviour at singular points $x_0$.
16 Uhr c.t., at Zoom

06.02.23Renann Lipinski Jusinskas, Prague
In this talk I will present a worldsheet model obtained from "twisting" the target space CFT of conventional string theory. The physical spectrum becomes finite and corresponds to the massless spectrum of closed strings plus a single massive level of the open string. The underlying idea is to explore the field/string theory interface in both directions. On one hand, the goal is to generate effective field theories describing massive higher spins using worldsheet methods. Conversely, we may try to use field theory methods to obtain a systematic description of string scattering amplitudes using field theory methods.
16 Uhr c.t., Munich, Theresienstr. 37A, R. 348, at Zoom

Joint seminar series on Mathematical Physics and String Theory

Koordination: Kontakt:

Ilka Brunner (LMU München)
Nils Carqueville (Universität Wien)
Hans Jockers (JGU Mainz)
Peter Mayr (LMU München)
Simone Noja (Universität Heidelberg)
Ingmar Saberi (LMU München)
Ivo Sachs (LMU München)
Johannes Walcher (Universität Heidelberg)

Mascha Ringe

userID: mringe

Past seminars winter 2022/2023

06.02. Renann Lipinski Jusinskas (Prague) "Asymmetrically twisted strings"
30.01. Konstantin Wernli (University of Southern Denmark) "On Globalization of Perturbative Partition Functions in the Batalin-vilkovisky formalism"
09.01. Nicolo Piazzalunga (Uppsala U.) "The index of M-theory"
19.12. Niccolo Cribiori & Ralph Blumenhagen (Max Planck Institute for Physics, Munich) "Cobordism, K-theory and tadpoles"
12.12. Ida Zadeh (JGU Mainz) "Heterotic Strings on T3/Z2, Nikulin involutions and M-theory"
05.12. Nikita Nekrasov (Stony Brook U.) "Anyons hiding in gauge theory in two, three and four dimensions"
28.11. Enno Keßler (MPI-M Bonn) "Super stable maps"
14.11. Raghu Mahajan (Stanford U.) "ZZ instanton amplitudes in minimal string theory at one-loop order"
31.10. Lorenz Eberhardt (IAS) "Unitarity cuts of the worldsheet"
24.10. Albrecht Klemm (Bonn U.) "Feynman integrals, Calabi-Yau geometries and integrable systems"

Past seminars summer 2022

18.07. Hossein Movasati (IMPA, Brasil) "Modular and automorphic forms and beyond"
27.06. Sara Pasquetti (U. of Milano-Bicocca) "Rethinking mirror symmetry as a local duality on fields"
20.06. Heeyeon Kim (Rutgers U.) "Path integral deviations of K-theoretic Donaldson invariants"
30.05. Maxim Zabzine (Uppsala U.) "The index of M-theory and equivariant volumes"
23.05. Leonardo Rastelli (Stony Brook U.) "On the 4D SCFTs/VOAs correspondence"
16.05. Fabian Hahner (Heidelberg U.) "Derived pure spinor superfields"
09.05. Urs Schreiber (Prague U.) "Anyonic Defect Branes and Conformal Blocks in Twisted Equivariant Differential K-Theory"
02.05. Murad Alim (Hamburg U.) "Non-perturbative quantum geometry, resurgence and BPS structures"
25.04. Minhyong Kim (U. of Warwick) "Quantum Field Theory as Mathematical Formalism: The Case of Arithmetic Geometry"

Past seminars winter 2021/2022

07.02. Jakob Palmkvist (Orebro U.) "Nonlinear realisations of Lie superalgebras"
31.01. Tudor Dimofte (U. Davies & Edinburgh) "A QFT for non-semisimple TQFT"
24.01. Surya Raghavendran (Perimeter) "Twisted S-duality"
17.01. Daniel Roggenkamp (U. Mannheim) "Defects and affine Rozansky-Witten models"
10.01. Eric Sharpe (Virginia Tech.) "An introduction to decomposition"
20.12. Yongbin Ruan (Zhejiang University) "Geometric Langlands and coadjoint orbits"
13.12. Justin Hilburn (Perimeter) "2-Categorical 3d Mirror Symmetry"
06.12. Mykola Dedushenko "Quantum algebras and SUSY interfaces"
29.11. Kevin Costello (Perimeter) "Self-dual Yang-Mills and anomaly cancellation on twistor space"
22.11. Ingmar Saberi (LMU) "Twisted eleven-dimensional supergravity and exceptional Lie algebras"
15.11. Pavel Putrov (ICTP Trieste) "Non-semisimple TQFTs and BPS q-series"
25.10. Michele Schiavina (ETH Zurich) "BV-BFV approach to General Relativity"

Past seminars summer 2021

05.07. Jan Manschot (Dublin) "Topological correlators of N=2* Yang-Mills theory"
21.06. Johanna Knapp (Melbourne) "Genus 1 fibered Calabi-Yau 3-folds with 5-sections - A GLSM perspective"
14.06. John Huerta (University of Lisbon) "Bundle gerbes on Lie supergroups"
17.05. Cyrill Closset (Birmingham) "Rank-1 5d SCFTs: Mapping out the U-plane"
10.05. Lukas Woike (Copenhagen) "Higher structures from modular categories"
03.05. Miguel Montero (Harvard) "Cobordisms, anomalies, and the Swampland"
26.04. Mathew Bullimore(Durham U.)"Towards a Mathematical Definition of the 3d Superconformal Index"
19.04. Francesco Benini (SISSA) "Superconformal Index and Gravitational Path Integral"
12.04. Shota Komatsu (CERN) "Three tales of de Sitter"
Past seminars winter 2020/2021

01.02. Andrea Brini "Quantum geometry and physics of Looijenga pairs"
25.01. Simeon Hellerman "The Large Quantum Number Expansion: Some Recent Developments"
11.01. Kasia Rejzner "BV-BFV formalism in perturbative AQFT"
14.12. Dmitri Bykov "Sigma models as Gross-Neveu models"
07.12. Susanne Reffert (U. Bern) "The large charge expansion"
16.11. Owen Gwilliam (U. of Massachusetts) "Centers of higher enveloping algebras and bulk-boundary systems"
09.11. Ilka Brunner (LMU) "Flow Defects and Phases of gauged linear sigma models"
02.11. Mathias Traube (MPI Munich) "Cardy Algebras, Sewing-Constraints and String-Nets"
26.10. Theo Johnson-Freyd (Perimeter) "3+1d topological orders with (only) an emergent fermion"
19.10. Chris Beem (Oxford U.) "Hall-Littlewood Chiral Rings and Derived Higgs Branches"
12.10. Ezra Getzler (Northwestern U.) "Gluing local gauge conditions in BV quantum field theory
Past seminars summer 2020

20.07. Thorsten Schimannek (Vienna U.) "The quantum geometry of genus one fibered Calabi-Yau threefolds"
13.07. Thomas Creutzig (Alberta) "Algebraic blow-up"
29.06. Alberto Cattaneo (Zurich) "Hamilton-Jacobi and Quantum Chern-Simons on Cylinders"
22.06 Simone Noja (Como) "On Some Global and Local Problems in Supergeometry"
15.06. Tomas Prochazka (LMU) "Grassmannian VOAs"
08.06. Ingmar Saberi (Heidelberg) "Holomorphic field theories and higher symmetries"
25.05. Christoph Chiaffrino (LMU) “Planar Quantum A-Infinity Algebras”
18.05. Nils Carqueville (Vienna) “An introduction to functorial TQFT with defects”
11.05. Ivo Sachs (LMU) "From BV to string theory and back"