# The Theory of Causal Fermion Systems

## Community

Below you find a list of active researchers working on various aspects of the Theory of Causal Fermion Systems with their contact details and a short description of their research interests. For general questions you can also contact us at mail@causal-fermion-system.com.

## Prof. Dr. Claudio Dappiaggi

*Associate ProfessorDipartimento di Fisica*

*Università degli Studi di Pavia, Italy*

Contact

I am interested mainly in the connections between causal fermion systems and algebraic quantum field theory. I worked on the existence theory for the linearized field equations and the construction of Green’s operators. I would like to understand better how interacting quantum fields can be described in the framework of causal fermion systems.

For my full research interests see my personal website.

## Prof. Dr. Felix Finster

*Chair of Mathematics (Lehrstuhl)*

*Universität Regensburg, Germany*

Contact

I thought for many years about questions which eventually led to causal fermion systems. What began as a hobby evolved into my main area of research.

For my research interests see also my personal website.

## Prof. Dr. Niels G. Gresnigt

*Associate Professor*

*Xi’an Jiaotong-Liverpool University, Suzhou, China*

Contact

I am interested in the division and Clifford algebraic foundations that underlie the Standard Model, its embedding within causal fermion systems and subsequent phenomenological implications in high energy physics.

For my full research interests see my personal website.

## Prof. Dr. José M. Isidro

*Full Professor (catedrático)Universidad Politécnica de Valencia, Spain*Contact

With respect to causal fermion systems, I am mainly interested in thermodynamical principles and notions like area, entropy and temperature, also in connection to the work by T. Padmanabhan.

For my full research interests see my ORCID webpage.

## Prof. Dr. Niky Kamran

*James McGill ProfessorMcGill University, Montréal, Canada*Contact

I am interested mainly in topological and geometric aspects of causal fermion systems. More recently, I got interested in the connections to complex geometry and related Fock space constructions.

For my full research interests see my personal website.

## Prof. Dr. Antonino Marcianò

*Tenured Full ProfessorDepartment of Physics, Fudan University, Shanghai, China &INFN, Laboratori Nazionali di Frascati, Italy &INFN, Sezione Roma “Tor Vergata”, Italy*Contact

I am interested both in the unification of forces and quantum gravity aspects of causal fermion systems, and its phenomenological implications in cosmology, astroparticle and high energy physics.

For my full research interests see my personal website.

## Prof. Dr. Heiko von der Mosel

*Full ProfessorRWTH Aachen University, Germany*Contact

I am interested in causal fermion systems from the perspective of analysis and the calculus of variations. In particular, I worked on estimates of the Hausdorff dimension of the support of minimizing measures and would like to generalize and improve these results.

For my full research interests see my personal website.

## Prof. Dr. Tejinder P. Singh

*Professor of PhysicsTata Institute of Fundamental Research, Mumbai, India &*

*Inter-University Centre for Astronomy and Astrophysics, Pune, India*

Contact

I am interested in causal fermion systems from the perspective of quantum gravity and the unification of fundamental forces.

For my full research interests see my personal website.

## Prof. Franz Gmeineder, Dphil

*Assistant Professor (TT-Professur)*

*Fachbereich Mathematik und Statistik*

*Universität Konstanz, Germany*

*Contact*

I am interested in causal fermion systems from the perspective of the calculus of variations and analysis. Within this area, a main focus is on establishing a solid existence theory in the infinite dimensional setting.

For my full research interests see my personal website.

## Prof. Dr. Niki Kilbertus

*TUM Assistant Professor and group leader Helmholtz AI**Helmholtz AI, **Neuherberg, Germany*

Contact

I am interested in causal fermion systems from the perspective of machine learning and nonlinear optimization.

For more information see my personal website.

## Dr. Simone Murro

*Assistant Professor (ricercatore a tempo determinato – type A)*

Dipartimento di Matematica*Università di Genova & INFN, Sezione di Genova, Italy*Contact

I am interested in various aspects of causal fermion systems. In particular, I find challenging the Cauchy problem in the setting of causal fermion systems. Also, I would like to get a connection to noncommutative algebraic geometry. During my PhD time, I analyzed the fermionic signature operator in explicit examples and constructed corresponding pure, quasifree Dirac states.

For my full research interests see my personal website.

## Moritz Reintjes, PhD

I got in contact with causal fermion systems mainly when working on the fermionic signature operator in globally hyperbolic spacetimes, and before that when studying the fermionic projector in FRW spacetimes. I am currently interested in the question of how entanglement arises in the Theory of Causal Fermion Systems.

For my full research interests see my personal website.

## Dr. Erik Curiel

*Assistant ProfessorLichtenberg Group for History and Philosophy of Physics, Universität Bonn, Germany &*

*Black Hole Initiative, Harvard University, USA*

Contact

## PD Dr. Margarita Kraus

*Senior Lecturer* (Akademische Rätin)*Universität Mainz, Germany,*Contact

I am interested mainly in the regularized Hadamard expansion and the implications on causal fermion systems constructed on a globally hyperbolic Lorentzian manifold.

For more information see my personal website.

## PD Dr. Olaf Müller

*Senior Lecturer* (Akademischer Rat)*Humboldt-Universität zu Berlin, Germany,*Contact

I am interested mainly in Lorentzian spectral geometry and infinite-dimensional analysis for causal fermion systems.

For more information see my personal website.

## Dr. Daniela Schiefeneder

*Senior Lecturer**Universität Innsbruck, Austria*Contact

I am interested in causal fermion systems from the perspective of analysis and the calculus of variations. In my PhD thesis, I proved for a large class of causal variational principles that the support of minimizing measures has an empty interior. In the meantime, we improved these results. I would like to go further in this direction.

For more information see my personal website.

## PD Dr. habil Jürgen Tolksdorf

*Institut für Theoretische Physik*

*Universität Leipzig, Germany*

Contact

I worked on the perturbation theory for the fermionic projector. I am interested in the connections between causal fermion systems, gauge theories and quantum field theory.

## Dr. Jan-Hendrik Treude

*Department manager (Fachbereichsreferent)F*

*achbereich Mathematik und Statistik*

Universität Konstanz, Germany

Universität Konstanz, Germany

*Contact*

I learned about causal fermion systems when being a PhD student in Regensburg. Now I am working jointly with Felix Finster and Sebastian Kindermann on the textbook “An Introductory Course on Causal Fermion Systems“.

## Dr. Robert H. Jonsson

*Postdoctoral ResearcherNordita, KTH Royal Institute of Technology and Stockholm University, Sweden*

Contact

I am particularly interested in quantum information theoretical aspects of causal fermion systems, and in the application of optimization and machine learning methods to the search for new minimizers of the causal action principle.

## Dr. Johannes Kleiner

*Postdoctoral ResearcherMunich Center for Mathematical Philosophy*

*Ludwig-Maximilians-Universität München, Germany*

Contact

In my PhD thesis, I worked on conservation laws for causal fermion systems formulated in terms of surface layer integrals. Moreover, I am mostly interested in the connections to the foundations of quantum mechanics (the measurement problem and collapse phenomena).

For my full research interests see my personal website.

## Dr. Claudio F. Paganini

*Postdoctoral Researcher*

*Universität Regensburg &*

Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Potsdam, Germany

Contact

Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), Potsdam, Germany

With respect to the causal fermion systems, I am mostly interested in the physical aspects of the theory. The interpretation of the action principle. A possible connection with Fröhlich’s ETH formulation of Quantum Theory, and how the theory relates to other attempts of unification/quantum gravity. Furthermore, I am interested in any attempt to come up with predicitions of the theory.

For my full research interests see my private website.

## Sami Abdallah

*PhD Student*

*Universität Regensburg, Germany*

Contact

My PhD thesis is concerned with the study of black holes and their horizons in the setting of causal fermion systems. I am particularly interested in geometrodynamics, and will be investigating how the area of the horizon behaves dynamically, and drawing a relation to blackhole entropy.

## Patrick Fischer

*PhD Student*

*Universität Regensburg, Germany*

Contact

I wrote my master thesis on group field theory with Daniele Oriti. My PhD thesis is concerned with the connection between causal fermion systems and quantum gravity in discrete spacetimes.

## Christoph Krpoun

*PhD Student*

*Universität Regensburg, Germany*

Contact

My PhD thesis is concerned with the fermionic signature operator in black hole spacetimes and spectral geometry, also in connection to the geometric structures of a causal fermion system.

## Marco van den Beld Serrano

*PhD Student*

*Universität Regensburg, Germany*

Contact

In my master thesis in Tübingen I worked on low regularity inextendibility of spacetimes and the construction of a unique maximal boundary. In my PhD thesis, the goal is to explore the mechanism of baryogensis which arises in the context of causal fermion systems. I want to work out this mechanism for different spacetimes.

## Former Group Members

## Dr. Maximilian Jokel

My PhD thesis was concerned with the analysis of the Euler-Lagrange equations in curved spacetime. The goal is to understand the dynamics of causal fermion systems near the singularity of a black hole.

## Sebastian Kindermann

In my master thesis, I analyzed local gauge freedom and gauge fixing for causal fermion systems. This involved the construction of special charts (so-called symmetric wave charts) of the manifold of regular points of ${\mathcal{F}}$. I am also interested in physical applications of causal fermion systems, in particular in connection with entanglement.

I am working jointly with Felix Finster and Jan-Hendrik Treude on the textbook “An Introductory Course on Causal Fermion Systems“.

## Dr. Christoph Langer

My PhD thesis was concerned with the existence theory for minimizers of causal variational principles, both in the non-compact setting and for the causal action principle on an infinite-dimensional Hilbert space imposing symmetries.

## Dr. Magdalena Lottner

My PhD thesis was concerned with the question how entanglement entropy can be defined and computed in the setting of causal fermion systems. I would like to also understand the relation to the information paradox. Moreover, I am interested in aspects of infinite-dimensional analysis and in the existence theory for the linearized field equations in the static setting.

## Dr. Marco Oppio

I am interested in the interplay between the mathematical and physical structures of causal fermion systems and standard quantum theories. Currently, I have been working on the application of operator algebras to causal fermion systems, with a special focus on Dirac systems in Minkowski space.

## Dr. Saeed Zafari

My PhD thesis was concerned with the geometry of causal fermion systems, mainly in the case of spin dimension one. In particular, how can one define notions of connection and curvature? What are the relations between the local geometry and the global “quantum geometry” of the causal fermion system?