# The Theory of Causal Fermion Systems

## Events

Banff International Research Station, Oaxaca, México

- Tuesday, June 14, 2022: Video, Slides
*F. Finster*, Universität Regensburg, “An introduction to causal fermion systems and the causal action principle”

## Working Seminar "Mathematical Physics" in the Summer Term 2022

The seminar takes place in hybrid format, both in the lecture room and via Zoom. If you would like to attend the talks, please let us know via e*mail*. We will send you the Meeting-ID and password.

- Thursday, April 28, 2022 at 8:30 (always Brussels time)
*Felix Finster*, Universität Regensburg, “A glueing construction for linearized fields of causal variational principles” - Friday, April 29, 2022, at 14:30: YouTube, Notes
*Carla Cederbaum*, Universität Tübingen, “Coordinates are messy” - Thursday, May 5, 2022 at 8:30,
*Christoph Krpoun*, Universität Regensburg, “The Dirac equation in the Kerr geometry I” - Friday, May 6, 2022, at 14:30
*Robert Jonsson*, Max-Planck-Institut für Quantenoptik, Garching, “Entanglement duality in free supersymmetric systems” - Thursday, May 12, 2022 at 8:30,
*Tobias Butzmann*, Universität Regensburg, “Numerical analysis of the causal action principle with symmetries” - Friday, May 13, 2022, at 14:30: YouTube, Notes-1, Notes-2, Notes-3
*Heiko von der Mosel*, RWTH Aachen, “Symmetric criticality with applications in geometric knot theory” - Thursday, May 19, 2022 at 8:30,
*Claudio Paganini*, Universität Regensburg, “Connecting non Riemannian measure theories and causal fermion systems I” - Friday, May 20, 2022 at 14:30: YouTube, Slides
*Jinzhao Wang*, ETH Zürich, “Outer entropy and the Bartnik mass” - Thursday, May 26, 2022 at 8:30: holiday
- Friday, May 27, 2022 at 14:30 (online),
*Claudio Paganini*, Universität Regensburg, “Connecting non Riemannian measure theories and causal fermion systems II” - Thursday, June 2, 2022 at 8:30,
*Christoph Krpoun*, Universität Regensburg, “The Dirac equation in the Kerr geometry II” - Friday, June 3, 2022 at 14:30 (online): Slides
*Annegret Burtscher*, Radboud University, Nijmegen, “On limits of smooth spacetimes” - Thursday, June 9, 2022 at 8:30,
*Johannes Wurm*, Universität Regensburg, “Energy and momentum for asymptotically flat causal fermion systems” - Friday, June 10, 2022 at 14:30 (online): YouTube
*Hanno Sahlmann*, FAU Erlangen, “Loop quantum gravity: From graphs and groups to black holes” - Thursday, June 16, 2022 at 8:30: holiday
- Friday, June 17, 2022 at 14:30 (online): YouTube, Slides
*Fabien Besnard*, EPF Paris, “Hype-free noncommutative geometry” - Thursday, June 23, 2022 at 8:30 (online): YouTube
*Nicola Pinamonti*, Università di Genova, “Thermal properties of quantum fields near spherically symmetric apparent horizon and Black Hole thermodynamics” - Friday, June 24, 2022 at 14:30: no talk (LQP meeting in Erlangen)
- Thursday, June 30, 2022 at 8:30 (hybrid):
*Christoph Krpoun*, Universität Regensburg, “The Dirac propagator in the Reissner-Nordström geometry in Eddington-Finkelstein coordiants” - Friday, July 1, 2022 at 14:30:
*student talk* - Thursday, July 7, 2022 at 8:30,
*Johannes Burger*, Universität Regensburg, “Fermionic operator algebras for causal fermion systems” - Friday, July 8, 2022 at 14:30:
**cancelled***Claudio Dappiaggi,*Università degli Studi di Pavia, “The anti-Hawking effect” - Thursday, July 14,
**15th Colloquium****“Mathematics and Foundations of Quantum Theory”**jointly with Dirk Deckert (München), Peter Pickl (Tübingen) and Wojciech Dybalski (Poznan) - 14:15-15:00:
*Azam Jahandideh*, Adam Mickiewicz University Poznan, “Stochastic quantization of two-dimensional Φ^{4}Euclidean quantum field theory” - 15:00-15:45:
*Umut Özcan*, Universität Tübingen, “Effective dynamics of a dense Fermi gas” - 16:00-17:00:
*Giuseppe de Nittis*, Pontificia Universidad Católica de Chile, “The magnetic spectral triple: Applications and open questions”

- 14:15-15:00:
- Friday, July 15, 2022 at 14:30,
*Sami Abdallah*, Universität Regensburg, tba - Thursday, July 21, 2022 at 8:30, tba
- Friday, July 22, 2022 at 14:30, tba
- Tuesday, July 26, 2022 at 14:15 in M201:
*José M. Isidro*, Universidad Politécnica de Valencia, “On the cosmological constant as a quantum operator” - Thursday, July 28, 2022 at 8:30,
*Daniela Schiefeneder,*Universität Innsbruck, “On the support of minimizers of causal variational principles on the sphere” - Friday, August 26, 2022 at 14:30: Slides
*Niky Kamran*, McGill University, Montréal, “The anisotropic Calderon problem on 3-dimensional conformally Staeckel manifolds”

## Past Events

## Working Seminar "Mathematical Physics" in the Winter Term 2021/22

- Thursday, October 21, 2021, at 8:30 (always Brussels time):
*Magdalena Lottner*, Universität Regensburg, “The fermionic entanglement entropy in the Schwarzschild geometry I” - Friday, October 22, 2021, at 14:30
*Magdalena Lottner*, Universität Regensburg, “The fermionic entanglement entropy in the Schwarzschild geometry II” - Thursday, October 28, 2021, at 8:30
*Claudio Paganini*, Universität Regensburg, “Frequency splitting and spatial localization: Quantifying Hegerfeldt’s theorem” - Friday, October 29, 2021, at 14:30
*Felix Finster*, Universität Regensburg, “The Hadamard expansion and its regularization” - Thursday, November 4, 2021, at 8:30: YouTube, Slides
*Clemens Sämann*, Universität Wien, “Synthetic (metric) methods in General Relativity and Lorentzian geometry – Part 1: Lorentzian length spaces” - Friday, November 5, 2021, at 14:30: YouTube, Slides
*Clemens Sämann*, Universität Wien, “Synthetic (metric) methods in General Relativity and Lorentzian geometry – Part 2: Applications” - Thursday, November 11, 2021, at 8:30
*Christoph Krpoun*, Universität Regensburg, “Spin structures and the Dirac equation curved spacetime I” - Friday, November 12, 2021, at 10:15: YouTube, Slides
*Ettore Minguzzi*, Università degli Studi di Firenze, “Causality theory for cone structures and the distance formula” - Thursday, November 18, 2021, at 8:30
*Thomas Semler*, Universität Regensburg, “Topologische Fermionsysteme und Vektorbündel” - Friday, November 19, 2021, at 14:30: Youtube
*Jeff Jauregui*, Union College, “General relativistic mass in low regularity” - Thursday, November 25, 2021, at 8:30
*Christoph Krpoun*, Universität Regensburg, “Spin structures and the Dirac equation curved spacetime II” - Friday, November 26, 2021, at 14:30: Youtube
*Demetre Kazaras*, Duke University, “Harmonic functions, mass, and stability of the positive mass theorem” - Thursday, December 2, 2021, at 8:30
*Felix Finster*, Universität Regensburg, “A Gauß-Bonnet theorem for causal fermion systems” - Friday, December 3, 2021, at 14:30: YouTube, Slides
*Gandalf Lechner*, Universität Erlangen, “Constructions of conformal QFTs from Borchers triples: non-local examples” - Thursday, December 9, 2021, at 8:30
*Johannes Wurm,*Universität Regensburg, “Towards energy-momentum of a causal fermion system” - Friday, December 10, 2021, at 14:30: YouTube
*Christian Hainzl*, LMU München, “Bosonic features of fermonic systems” - Thursday, December 16, 2021, at 8:30
*Maximilian Jokel*, Universität Regensburg, “Second variations of the causal action for regularized Dirac sea configurations” - Friday, December 17, 2021, at 14:30: YouTube, Slides
*Daniele Volpe,*Università di Trento, “Paracausal deformations of globally hyperbolic spacetimes and their applications in AQFT” - Thursday, January 13, 2022, at 8:30
*Sami Abdallah,*Universität Regensburg, “The black hole dynamics of a causal fermion system” - Friday, January 14, 2022, at 14:30
*Felix Finster,*Universität Regensburg, “A mechanism for dark matter and dark energy in causal fermion systems” - Thursday, January 20, 2022, at 8:30
*Michelle Frankl,*Universität Regensburg, “On the Euler-Lagrange equations of the homogeneous causal action principle” - Friday, January 21, 2022, at 14:30: YouTube, Slides
*Tejinder Singh*, Tata Institute, Mumbai, “Relativistic weak quantum gravity and its significance for the standard model of particle physics” - Thursday, January 27, 2022, at 8:30
*Saeed Zafari,*Universität Regensburg, “Connections on two-dimensional smooth causal fermion systems” - Friday, February 4, 2022, at 14:30:
**14th Colloquium****“Mathematics and Foundations of Quantum Theory”**jointly with Dirk Deckert (München), Peter Pickl (Tübingen) and Wojciech Dybalski (Poznan)- 13:30
*Daniela Cadamuro*, Universität Leipzig: “Fermionic integrable models and graded Borchers triples” - 15:00
*Miguel Ballesteros*, UNAM Mexico City: “Levinson theorem for matrix-valued Schrödinger operators on the discrete line“ - 16:30
*A. Shadi Tahvildar-Zadeh*, Rutgers University: “Classical and quantum laws of motion for singularities of spacetime”

- 13:30
- Thursday, February 10, 2022, at 8:30
*Johannes Burger*, Universität Regensburg, “The extended Hilbert space of a causal fermion system” - Friday, February 11, 2022, at 14:30: YouTube, Slides
*Julia Harz*, Technische Universität München, “Probing the mechanism behind the matter-antimatter asymmetry” - Thursday, February 17, 2022, at 8:30
*Magdalena Lottner*, Universität Regensburg, “On a class of integral operators with discontinuous symbols”

## Working Seminar "Mathematical Physics" in the Summer Term 2021

- Thursday, April 15, 2021, at 8:30 (always Brussels time): YouTube
*Felix Finster,*Universität Regensburg, “Baryogenesis in causal fermion systems: The adiabatic projection of the regularization” - Friday, April 16, 2021, at 14:30:
*Klaus Sibold*, Universität Leipzig, “Perturbative quantization of Einstein-Hilbert gravity” - Thursday, April 22, 2021, at 8:30:
*Marco Oppio*, Universität Regensburg, “Hölder continuity of the integrated causal Lagrangian in Minkowski space II” - Friday, April 23, 2021, at 14:30: YouTube, Slides
*Peter Schupp*, Jacobs University, Bremen, “Graded geometry and gravity” - Thursday, April 29, 2021, at 8:30:
*Magdalena Lottner*, Universität Regensburg, “Elliptic estimates for static causal fermion systems” - Friday, April 30, 2021, at 14:30: YouTube
*Rainer Verch*, Universität Leipzig, “Temperature and entropy-area relation of quantum matter near spherically symmetric outer trapping horizons” - Thursday, May 6, 2021, at 8:30: YouTube, Slides
*Thomas Schücker*, Aix-Marseille Université, “Minimal symmetry breaking of the cosmological principle and dominating dust” - Friday, May 7, 2021, at 14:30: YouTube, Slides
*Bernard Kay*, University of York, “A product picture for quantum electrodynamics” - Thursday, May 13, 2021: holiday, no talk!
- Friday, May 14, 2021, at 14:30: YouTube, Slides
*Jürg Fröhlich*, ETH Zürich, “Quantum dynamics of systems under repeated observation” - Thursday, May 20, 2021, at 8:30: YouTube
*Christoph Langer*, Universität Regensburg, “The Euler-Lagrange equations of the homogeneous causal variational principle II” - Friday, May 21, 2021, at 14:30: YouTube
*Daniele Oriti*, Ludwig-Maximilians-Universität München, “Tensorial group field theories: quantum geometry and emergent cosmology” - Thursday, May 27, 2021, at 8:30:
*Felix Finster*, Universität Regensburg, “On the causal fermion system describing the standard model” - Friday, May 28, 2021, at 14:30: YouTube, Slides
*Niky Kamran*, McGill University, Montréal, “Ramified local isometric embeddings of singular Riemannian metrics” - Thursday, June 3, 2021: holiday, no talk!
- Friday, June 4, 2021, at 14:30: YouTube, Slides
*Stefan Teufel*, Universität Tübingen, “Adiabatic theorems and linear response in the thermodynamic limit” - Thursday, June 10, 2021, at 8:30:
*Maximilian Jokel*, Universität Regensburg, “Inverting the Second Variation of the Regularized Causal Action” - Friday, June 11, 2021, at 14:30: YouTube, Slides
*Klaas Landsman*, Radboud University, Nijmegen, “Quantization: The big picture” - Thursday, June 17, 2021, at 8:30:
*Marco Oppio*, Universität Regensburg, “An algebraic model for causal fermion systems” - Thursday, June 24, 2021, at 8:30:
*Saeed Zafari*, Universität Regensburg, “Circumference and Gauß curvature for causal fermion systems in spin dimension one” - Friday, June 25, 2021, at 14:30: YouTube, Slides
*Miguel Manzano*, Universidad de Salmanca, “Null shells: general matching across null boundaries and connection with cut-and-paste formalism” - Thursday, July 1, 2021, at 8:30:
*Johannes Wurm*, Universität Regensburg, “On the area constraint for the mass of time-dependent spacetimes” - Friday, July 2, 2021, at 14:30:
**13th Colloquium****“Mathematics and Foundations of Quantum Theory”**jointly with Dirk Deckert (München), Peter Pickl (Tübingen) and Wojciech Dybalski (Poznan)- 15:00
*Sergio Albeverio*and*Francesco De Vecchi*, Universität Bonn: “Stochastic methods in quantum fields: introduction and applications to scalar fields” - 16:30
*Massimiliano Gubinelli*, Universität Bonn: “Some aspects of the stochastic quantisation of the $\phi^4_3$ model”

- 15:00
- Thursday, July 8, 2021, at 8:30:
*Michelle Frankl*, Universität Regensburg, “Causal variational principles in the homogeneous setting: The Euler-Lagrange equations in the compact case” - Friday, July 9, 2021, at 14:30: YouTube, Slides
*Robert Oeckl*, UNAM Morelia, “alpha-Kähler quantization” - Thursday, July 15, 2021, at 8:30:
*Tobias Butzmann*, Universität Regensburg, “Causal fermion systems with symmetries” - Friday, July 16, 2021, at 14:30: YouTube, Slides
*Moritz Reintjes*, Universität Konstanz, “Uhlenbeck compactness and optimal regularity in Lorentzian geometry and for Yang-Mills gauge theories” - Friday, July 23, 2021, at 14:30: YouTube, Slides
*Kasia Rejzner*, University of York, “C$^*$-algebraic formulation of interacting quantum field theory applied to fermions“

## Working Seminar "Mathematical Physics" in the Winter Term 2020/21

- Friday, October 23, 2020, at 14:30 (always Brussels time): YouTube
*José M. Isidro*, Universidad Politécnica de Valencia, “An introduction to the chiral anomaly” - Friday, November 6, 2020, at 15:00: YouTube, Slides
*Michael Kiessling*, Rutgers University, “On the general-relativistic quantum-mechanical spectrum of hydrogenic ions” - Thursday, November 12, 2020, at 8:30:
*Magdalena Lottner*, Universität Regensburg, “The chain rule for causal fermion systems in the infinite-dimensional setting and Hölder continuity of the causal Lagrangian” - Friday, November 13, 2020, at 14:30: YouTube, Notes
*Felix Finster*, Universität Regensburg, “A mechanism for baryogenesis in causal fermion systems” - Thursday, November 19, 2020, at 8:30:
*Marco Oppio*, Universität Regensburg, “Hölder continuity of the integrated causal Lagrangian in Minkowski space” - Friday, November 20, 2020, at 14:30: YouTube, Slides
*Claudio Paganini*, Universität Regensburg and Albert-Einstein-Institut, Potsdam, “Incompatibility of frequency splitting and spatial localization: A quantitative analysis of Hegerfeldt’s theorem” - Thursday, November 26, 2020, at 8:30:
*Christoph Langer*, Universität Regensburg, “The Euler-Lagrange equations of the homogeneous causal variational principle” - Friday, November 27, 2020, at 14:30: Video
*Eduardo Guendelman*, Ben Gurion University, “Non-canonical volume-form formulation of modified gravity theories and cosmology“ - Thursday, December 3, 2020, at 8:30: YouTube
*Felix Finster*, Universität Regensburg, “A definition of entropy for causal fermion systems” - Friday, December 4, 2020, at 14:30: YouTube, Slides
*Wolfgang Spitzer*, Fernuniversität Hagen, “Entanglement entropy of the ideal Fermi gas” - Thursday, December 10, 2020, at 8:30:
*Maximilian Jokel*, Universität Regensburg, “Second variations of the causal action and baryogenesis” - Friday, December 11, 2020, at 14:30: YouTube
*Felix Finster*, Universität Regensburg, “The quantum state induced by the universal measure” - Thursday, December 17, 2020, at 8:30:
*Saeed Zafari*, Universität Regensburg, “The curvature of the Dirac sphere” - Thursday, January 7, 2021, at 8:30: YouTube
*Felix Finster,*Universität Regensburg, “Baryogenesis in causal fermion systems: Conservation laws and scalings” - Friday, January 8, 2021, at 14:30: YouTube
*Christoph Langer*, Universität Regensburg, “Causal variational principles in the infinite-dimensional setting: Existence of minimizers” - Thursday, January 14, 2020, at 8:30: YouTube, Slides
*Christoph Krpoun*, Humboldt-Universität zu Berlin, “The Dirac equation and its separation in the Reissner-Nordström geometry” - Friday, January 15, 2021, at 14:30: YouTube
*Peter Müller*, LMU München, “Entanglement entropy for quasi-free Fermi gases” - Thursday, January 21, 2021, at 8:30:
*Johannes Wurm*, Universität Regensburg, “On the definition of the total mass for causal fermion systems” - Friday, January 22, 2021, at 14:30: YouTube
*Albert Much*, Universität Leipzig, “Strict deformation quantization in curved spacetimes” - Thursday, January 28, 2021, at 8:30: YouTube
*Felix Finster,*Universität Regensburg, “Baryogenesis in causal fermion systems: The dynamics of the regularization” - Friday, January 29, 2021, at 14:30: YouTube, Slides
, Universität Leipzig, “Trace anomaly for chiral fermions”

Sami Abdallah - Thursday, February 4, 2021, at 8:30: YouTube, Slides
*Christiaan van de Ven,*Università di Trento, “Asymptotic equivalence of two strict deformation quantizations and applications to the classical limit” - Friday, February 5, 2021:
**Colloquium****“Mathematical Physics Regensburg-Munich”**jointly with LMU and TU Munich (co-organized with Dirk Deckert, Wojciech Dybalski and Peter Pickl)- 13:00
*Roderich Tumulka*, Universität Tübingen: YouTube, Slides

“Multi-time version of the Landau-Peierls formulation of quantum electrodynamics” - 14:30
*Felix Finster*, Universität Regensburg: YouTube, Slides

“Quantum states of causal fermion systems and collapse”

- 13:00
- Friday, February 12, 2021, at 14:30: YouTube
*Eric Ling*, Rutgers University, “Spacetime extensions of the big bang” - Thursday, February 25, 2021, at 8:30:
*Magdalena Lottner*, Universität Regensburg, “Towards an area law for the Klein-Gordon projector” - Friday, February 26, 2021, at 14:30: YouTube
*Claudio Paganini*, Universität Regensburg and Albert-Einstein-Institut, Potsdam, “Ideas on baryogenesis”

## Working Seminar "Mathematical Physics" in the Summer Term 2020

- Thursday, April 24, 2020, at 8:30 (always Brussels time):
*Felix Finster*, Universität Regensburg, “The nonlinear surface layer integral and the symmetrized Fock norm I” - Thursday, April 30, 2020, at 14:30:
*Felix Finster*, Universität Regensburg, “The nonlinear surface layer integral and the symmetrized Fock norm II” - Thursday, May 7, 2020, at 14:30:
*Felix Finster*, Universität Regensburg, “Extending the commutator inner product in a surface layer” - Friday, May 15, 2020, at 14:30: YouTube
*Saeed Zafari and Felix Finster*, Universität Regensburg, “Towards a Gauß-Bonnet theorem for causal fermion systems” - Friday, May 22, 2020 at 14:30:
*Claudio Paganini*, Universität Regensburg and Albert-Einstein-Institut, Potsdam, “The ETH formulation of quantum theory I” - Friday, May 29, 2020, at 14:30:
*Magdalena Lottner*, Universität Regensburg, “Entanglement entropy in the context of causal fermion systems” - Friday, June 5, 2020 at 14:30:
*Simone Murro*, Università di Trento, “On the Cauchy problem for symmetric hyperbolic systems on globally hyperbolic manifolds with timelike boundary” - Friday, June 12, 2020 at 14:30: YouTube
*Felix Finster*, Universität Regensburg, “Energy estimates and cone structures for the linearized field equations” - Friday, June 19:

No talk because of**LQP Workshop**(see below) - Friday, June 26, 2020 at 14:30: YouTube
*Miguel Sánchez Caja*, Universidad de Granada, “Some techniques related to Causality and Global Hyperbolicity” - Friday, July 3, 2020:
**Colloquium****“Mathematical Physics Regensburg-Munich”**jointly with LMU and TU Munich (co-organized with Dirk Deckert, Wojciech Dybalski and Peter Pickl)- 13:00
*Jens Mund*, Universidade Federal de Juiz de Fora and TU München, “Perturbative construction of a string-localized Dirac field in a Hilbert space representation of QED” - 14:30
*Claudio Dappiaggi*, Università degli Studi di Pavia, “Boundary conditions for Maxwell’s equations on globally hyperbolic spacetimes with timelike boundary”

- 13:00
- Friday, July 10, 2020:
**Colloquium****“Mathematical Physics Regensburg-Munich”**jointly with LMU and TU Munich (co-organized with Dirk Deckert, Wojciech Dybalski and Peter Pickl)- 13:00
*Vincenzo Morinelli*, Università degli Studi di Roma `Tor Vergata’, “Covariant homogeneous nets of standard subspaces” - 14:30
*Nicola Pinamonti*, Università di Genova, “Existence and uniqueness of solutions of the semiclassical Einstein equation in cosmology“

- 13:00
- Friday, July 17, 2020:
- 13:00
*Harald Grosse,*Universität Wien, “A solvable noncommutative Quantum Field Theory” - 14:30
*Claudio Paganini*, Universität Regensburg and Albert-Einstein-Institut, Potsdam, “The ETH formulation of quantum theory II”

- 13:00
- Friday, July 24, 2020 at 14:30:
*Marco Oppio*, Universität Regensburg, “Symmetrized nonlinear surface layer integrals: An example in Minkowski space”

## Seminar talks at Universität Tübingen, July 8 and 9, 2020

- Wednesday, 8 July 2020 (online via Zoom): YouTube, Slides
*Felix Finster*, Universität Regensburg, “Causal fermion systems and the causal action principle” - Thursday, 9 July 2020 (online via Zoom): YouTube, Slides
*Felix Finster*, Universität Regensburg, “A positive mass theorem for static causal fermion systems”

## First Virtual LQP Workshop, June 17-19, 2020

The workshop took place online. For details see the conference website.

*Magdalena Lottner*gave a talk on “Entropy in causal fermion systems” on June 19 at 14:20 British summer time (i.e. 15:20 local time in Germany).