Daniel Siemssen

Associate Lecturer in Mathematical Physics

University of York


I am currently an Associate Lecturer in Mathematical Physics at the University of York.

I completed my undergraduate degree in physics at the University of Hamburg (Germany) in 2011, and my PhD in mathematics at the University of Genoa (Italy) in 2015. Following that I held post-doctoral positions at the University of Warsaw (Poland) and the University of Wuppertal (Germany). After an interim professorship in Wuppertal, I joined the Department of Mathematics in York in 2019.

Some research interests: PDEs, differential operators on manifolds, microlocal analysis, functional analysis, mathematical physics, mathematical aspects of quantum field theory and quantum field theory in curved spacetimes.

Positions & Education


Associate Lecturer in Mathematical Physics

Department of Mathematics, University of York

Oct 2019 – Present York, U.K.

Interim Professor in Applied Mathematics

Department of Mathematics and Informatics, University of Wuppertal

Oct 2018 – Sep 2019 Wuppertal, Germany

Postdoctoral position

Department of Mathematics and Informatics, University of Wuppertal

Oct 2017 – Sep 2018 Wuppertal, Germany

Adiunkt naukowy (Assistant Professor)

Faculty of Physics, University of Warsaw

Oct 2015 – Sep 2017 Warsaw, Poland

Riemann Fellowship

Riemann Center for Geometry and Physics, University of Hannover

Mar 2015 – Jun 2015 Hannover, Germany

PhD studies

Department of Mathematics, University of Genoa

Jan 2012 – Feb 2015 Genoa, Italy

Diploma studies

Department of Physics, University of Hamburg

Oct 2005 – Jun 2011 Hamburg, Germany


An Evolution Equation Approach to Linear Quantum Field Theory

In this paper we describe the construction of various propagators based on an abstract theory of (non-autonomous) evolution equations …

The Cosmological Semiclassical Einstein Equation as an Infinite-Dimensional Dynamical System

We develop a comprehensive framework in which the existence of solutions to the semiclassical Einstein equation (SCE) in cosmological …

Pseudodifferential Weyl Calculus on (Pseudo-)Riemannian Manifolds

One can argue that on flat space $\mathbb{R}$ the Weyl quantization is the most natural choice and that it has the best properties (eg …

An Evolution Equation Approach to the Klein–Gordon Operator on Curved Spacetime

We develop a theory of the Klein–Gordon equation on curved spacetimes. Our main tool is the method of (non-autonomous) evolution …

Quantum Energy Inequalities in Pre-Metric Electrodynamics

Pre-metric electrodynamics is a covariant framework for electromagnetism with a general constitutive law. Its lightcone structure can …

Feynman Propagators on Static Spacetimes

We consider the Klein–Gordon equation on a static spacetime and minimally coupled to a static electromagnetic potential. We show …

Electromagnetic Potential in Pre-Metric Electrodynamics: Causal Structure, Propagators and Quantization

An axiomatic approach to electrodynamics reveals that Maxwell electrodynamics is just one instance of a variety of theories for which …

Enumerating Permutations by their Run Structure

Motivated by a problem in quantum field theory, we study the up and down structure of circular and linear permutations. In particular, …

Global Existence of Solutions of the Semiclassical Einstein Equation for Cosmological Spacetimes

We study the solutions of the semiclassical Einstein equation in flat cosmological spacetimes driven by a massive conformally coupled …

Scale-Invariant Curvature Fluctuations from an Extended Semiclassical Gravity

We present an extension of the semiclassical Einstein equations which couples n-point correlation functions of a stochastic Einstein …

Hadamard States for the Vector Potential on Asymptotically Flat Spacetimes

We develop a quantization scheme for the vector potential on globally hyperbolic spacetimes which realizes it as a locally covariant …


Currently (spring term 2020) I am teaching:

  • Quantum Information

Previously I taught:

  • Quantum Mechanics I
  • General Relativity
  • Measure and Integration Theory
  • Risk Theory
  • Introduction to Stochastics
  • Seminar on Wave Equations (Theory and Applications)
  • Exercises for Functional Analysis II
  • Exercises for Mathematical Introduction to Quantum Field Theory