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Dr. René Wittmann | |

Postdoc | |

Institut für Theoretische Physik II - Soft Matter | |

Heinrich-Heine-Universität Düsseldorf | |

Building 25.32 | |

Room O2.54 | |

Universitätsstraße 1 | |

D-40225 Düsseldorf, Germany | |

phone: +49-211-81-15934 | |

e-mail: wittmann <at> thphy.uni-duesseldorf.de |

2018-present |
Postdoctoral Research Fellow at the Institute for Theoretical Physics II, Heinrich-Heine University Düsseldorf, Germany |

2015-2018 |
Postdoctoral Research Fellow in the Soft Matter Theory group, University of Fribourg, Switzerland |

2015 |
PhD at the Institute for Theoretical Physics I, Friedrich-Alexander University Erlangen, Germany |

Examples of my research are linked below.

A full list of publications can be found on Google Scholar

I develop and apply microscopic theories for various soft matter systems, in and out of equilibrium, under complex external constraints. My favorite tool is classical density functional theory (DFT), which allows for calculating structural and thermodynamical equilibrium properties from first principles and can also be extended to describe dynamical systems. Both versions of DFT motivate deep mathematical questions regarding their microscopic and statistical foundations.

- Statistical and mathematical foundations of classical density functional theory (DFT)

**First figure:**ergodicity assumption leads to particle exchange in one dimension [PRE (2019)],

**Second figure:**dynamical DFT based on ordered ensemble predicts subdiffusion [Mol. Phys. (2021)].

- Development and application of geometry-based classical density functional theory (DFT)

**First figure:**scaling of hard bodies: the fundamental-measure DFT must describe all limits [JCP (2014)],

**Second figure:**phase diagram of hard spherocylinders (HSC) in 3d: improving the functional [JPCM (2016)],

**Third figure:**phase diagram of hard discorectangles (HDR) in 2d: free minimization and analytical isotropic-nematic transition [JCP (2017)].

- Topology of smectic liquid crystals in complex confinement

**First figure:**structural details of smectic states in annular confinement (DFT and experiment) [Nat. Comm. (2021)], [Pressebericht: Flüssigkristalle unter Stress],

**Second figure:**revealing the topological fine structure of spatially extended defects [PRL (2021)], [Physics Synopsis: Topology Inside a Liquid Crystal].

- Theoretical modeling and analysis of active particles

**First figure:**inertial active Ornstein-Uhlenbeck particles (AOUPs) and a diagram of their dynamic exponents [JPCM (2021)],

**Second figure:**active Brownian particles (ABPs) activated by food intake [PLOS One (2020)],

**Third figure:**unifying ABPs and AOUPs in a parental active model [JCP (2022)].

- Collective behavior of active particles close to equilibrium

**First figure:**phenomenology of active particles through effective attractions [JStat (2017)],

**Second figure:**activity-induced wetting transition in effective equilibrium [EPL (2016)],

**Third figure:**activity destabilizes the nematic phase of self-propelled rods [PRE (2018)],

**Fourth figure:**equilibrium-like relations between pressure, adsorption and surface tension at a curved wall [JCP (2019)].

- Dynamics under concurrent external constraints

**First figure:**stationary behavior of a stochastically reset particle under Lorentz force in an inhomogeneous magnetic field [PRR (2020)],

**Second figure:**multithermostat particle subject to a Lorentz force [New J. Phys. (2020)].

Commitment information: I accurately check the content of external links, but I do not enter into a commitment for their content. Responsible for the content of linked pages are the operating companies.