Welcome!
I am a postdoctoral researcher, last based at Leibniz University of Hanover's Institute for Theoretical Physics. In 2017, I have finished my PhD at the University of Regensburg's Department for Mathematics.
I have a background in:
 Mathematics, in particular the Calculus of Variations and Mathematical Physics
 Foundations of Physics and Unified Theories, in particular the Theory of Causal Fermion Systems
 Most recently: Models of Consciousness
Publications:
If you're interested in my scientific activity, have a look at my preprints and publications:
10.) Models of Consciousness (Entropy Special Issue)
Eds. Ian Durham, Johannes Kleiner, Yakov Kremnitzer, Jonathan Mason, Robert Prentner ISSN 109943009.) Progress and Visions in Quantum Theory in View of Gravity (Birkhäuser 2020)
Eds. Felix Finster, Domenico Giulini, Johannes Kleiner, Jürgen Tolksdorf ISBN 97830303894068.) On empirical welldefinedness of models of consciousness
Johannes Kleiner 10.31234/osf.io/jdcfh7.) Models of Consciousness
Johannes Kleiner arXiv:1907.032236.) A Class of Conserved Surface Layer Integrals for Causal Variational Principles
Felix Finster, Johannes Kleiner arXiv:1801.08715 J. Calc. Var. (2019) 58:385.) Dynamics of Causal Fermion Systems  Field Equations and Correction Terms for a New Unified Physical Theory (PhD Thesis)
University of Regensburg urn:nbn:de:bvb:355epub362894
I gratefully acknowledge the support of the Studienstiftung des Deutschen Volkes.4.) A Hamiltonian Formulation of Causal Variational Principles
Felix Finster, Johannes Kleiner arXiv:1612.07192 J. Calc. Var. (2017) 56:733.) Quantum Mathematical Physics (Birkhäuser 2015)
Eds. Felix Finster, Johannes Kleiner, Christian Röken, Jürgen Tolksdorf ISBN 97833192690232.) NoetherLike Theorems for Causal Variational Principles
Felix Finster, Johannes Kleiner arXiv:1506.09076 J. Calc. Var. (2016) 55:351.) Causal Fermion Systems as a Candidate for a Unified Physical Theory
Felix Finster, Johannes Kleiner arXiv:1502.03587 2015 J. Phys.: Conf. Ser. 626 012020
Events:
One of my hobbies is to organize scientific events, such as workshops, conferences, online seminars or public lecture series. Below is a small selection of events I've coorganized. Others are listed here.



Vita:
Here is my scientific CV, in case you're interested. Also, I am involved in the Campus Asyl mentoring program for refugees, the Studienstiftung/DAAD program an(ge)kommen and the Basic Research Community for Physics e.V.
If you're interested in which kind of teaching I have done, you can find more about this here.
Miscellanea:
Here is a video of my 20minute talk on the Models of Consciousness Conference at Oxford. It covers the fist few pages of my
"Models of Consciousness" paper arXiv:1907.03223. Since time was short, I had to rush a bit in the beginning. Sorry for that ;)
And here is a video which explains the Theory of Causal Fermion Systems to a general audience.
Unfortunately, it's only available in German.
Talks:
41.) Stochastic and NonLinear Correction Terms for the Linearized Field Equations of Causal Fermion Systems (Working Seminar on Mathematical Physics, University of Regensburg, October 2019)
40.) On the Mathematical Basis of Models of Consciousness (Mathematical Institute, University of Oxford, September 2019)
39.) Key Ideas of the Theory of Causal Fermion Systems (L'Agape Summer School on Theoretical Physics, Mézeyrac, France, July 2019)
38.) Models of Consciousness (Mathematical Institute, University of Göttingen, April 2019)
37.) Groundings of the Scientific Study of Consciousness (Modelling Consciousness Workshop, Dorfgastein, March 2019)
36.) Qualia and Symmetries (Munich Center for Mathematical Philosophy, LPS Colloquium, October 2018)
35.) Qualia and Symmetries (Seminar Progress and Visions in the Scientific Study of the MindMatter Relation, November 2018)
34.) Integrated Information Theory 3.0 (L'Agape Summer School on Theoretical Physics, Mézeyrac, France, July 2018)
33.) On Modelling Dual Aspect Monism (Workshop Models for DualAspect Monism, Johanneshof, Germany, June 2018)
32.) Lecturer at the International Spring School on Causal Fermion Systems (Regensburg University, February 2018)
31.) Quantum Einstein Equivalence: So close, no matter how far? (Revising Foundations of Physics Workshop, UCL, December 2017)
30.) Dynamics of Causal Fermion Systems (PhD Defence, Colloquium of Department for Mathematics, Regensburg University, September 2017)
29.) Correction Terms for Field Equations from Causal Fermion Systems (Working Seminar Mathematical Physics, Regensburg University, July 2017)
28.) La cuisine différente. Impressions from a new approach to fundamental physics (Quantum Lunch Seminar, University of Oxford, June 2017)
27.) Causal Variational Principles (PDE CDT Student Seminar, University of Oxford, June 2017)
26.) Causal Fermion Systems as a Candidate for a Unified Physical Theory (Lobster Lunch Seminar, University of Oxford, May 2017)
25.) Reductionism, ad absurdum? (Rethinking Foundations of Physics Workshop 2017, Dorfgastein, Austria, March 2017)
24.) Naked Singularities and the Penrose Inequality II (Working Seminar Mathematical Physics, Regensburg University, January 2017)
23.) Naked Singularities and the Penrose Inequality I (Working Seminar Mathematical Physics, Regensburg University, December 2016)
22.) Hamiltonian Time Evolution for Causal Variational Priciples (McGill University, Montreal, Canada, November 2016)
21.) Hamiltonian Time Evolution for Causal Variational Priciples (Harvard CMSA Members' Seminar, USA, September 2016)
20.) A New Candidate for a Unified Physical Theory (Harvard CMSA Mathematical Physics Seminar, USA, September 2016)
19.) Towards a Connection between Loop Quantum Gravity and Causal Fermion Systems (Working Seminar Mathematical Physics, University of Regensburg, Germany 2016)
18.) Spring School on Causal Fermion Systems (Regensburg, Germany, March 2016, Link)
17.) The jet bundle dynamics of causal fermion systems (Seminar Partial Differential Equations on Globally Hyperbolic Spacetimes and Working Seminar Mathematical Physics, Regensburg, October 2015)
16.) Physik und Transzendenz (Doktorandentagung Studienstiftung des deutschen Volkes, Bonn, November 2015)
15.) NoetherLike Theorems for Causal Variational Principles (Seminar Partial Differential Equations on Globally Hyperbolic Spacetimes and Working Seminar Mathematical Physics, Regensburg, October 2015)
14.) Causal Fermion Systems as a Candidate for a Unified Physical Theory (Conference "Quantum Theory: from foundations to technologies", Växjö, Sweden)
13.) Noetherlike theorems for causal variational principles (Working Seminar Mathematical Physics, Regensburg, June 2015)
12.) Imre Lakatos' Conception of Science (Doktorandentagung Studienstiftung des deutschen Volkes, Heidelberg, April 2015)
11.) Physik und Transzendenz (A series of three talks: "Albert Einstein  Naturwissenschaft und Religion", "Arthur Eddington  Wissenschaft und Mystizismus", "Carl Friedrich von Weizsäcker  Naturgesetz und Theodizee", based on essays of the three scientists which carry the same name as the talk; Neupfarrkirche Regensburg, October + November 2014)
10.) Causal fermion systems: a dynamical collapse theory? (Workshop DICE2014, Castiglioncello Italy, September 2014)
9.) Introduction to the theory of causal fermion systems (Oberseminar Mathematische Physik, LMU Munich, July 2014)
8.) QT and GR united? An introduction to causal fermion systems (Conference "Quantum Roundabout", Nottingham GB, July 2014)
7.) Paradigms of Modern Physics and Causal Fermion Systems (Series "Zurück zu den Zusammenhängen", Erlangen, April 2014)
6.) QT and GR united? A review of causal fermion systems (Working Seminar Mathematical Physics, Regensburg, May 2014)
5.) QT, QFT and GR united? Causal Fermion Systems: idea and paradigms behind (Paradigms of Modern Physics Workshop, Dorfgastein, March 2014)
4.) Mass and momentum of asymptotically flat manifolds (Seminar 'Recent Mathematical Progress in General Relativity', Regensburg, September 2013)
3.) The measurement problem in linear (quantum) theories (Working Seminar Mathematical Physics, Regensburg, May 2013)
2.) Locality in quantum theory (Philosophy of Quantum Theory Cabin Workshop, Hammerlochhäusle, March 2013)
1.) Experimental Status of Foundations of Gravity (Seminar Modern Experiments in Special and General Relativity, Heidelberg, 2012)
Last but not least:
My public email address: contact@jkleiner.de. My public PGP key. (What is PGP?) Further contact info here.