René Wittmann
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View article: Confined active particles with spatially dependent Lorentz force: An odd twist to the “best Fokker-Planck approximation”
Confined active particles with spatially dependent Lorentz force: An odd twist to the “best Fokker-Planck approximation” Open
We derive a version of the so-called “best Fokker-Planck approximation” (BFPA) to describe the spatial properties of interacting active Ornstein-Uhlenbeck particles in arbitrary spatial dimensions. In doing so, we also take into account th…
View article: A hitchhiker’s guide to active motion
A hitchhiker’s guide to active motion Open
Intelligent decisions in response to external informative input can allow organisms to achieve their biological goals while spending very little of their own resources. In this paper, we develop and study a minimal model for a navigational…
View article: Confined active particles with spatially dependent Lorentz force: an odd twist to the "best Fokker-Planck approximation"
Confined active particles with spatially dependent Lorentz force: an odd twist to the "best Fokker-Planck approximation" Open
We derive a version of the so-called "best Fokker-Planck approximation" (BFPA) to describe the spatial properties of interacting active Ornstein-Uhlenbeck particles (AOUPs) in arbitrary spatial dimensions. In doing so, we also take into ac…
View article: A Hitchhiker's Guide To Active Motion
A Hitchhiker's Guide To Active Motion Open
Intelligent decisions in response to external informative input can allow organisms to achieve their biological goals while spending very little of their own resources. In this paper, we develop and study a minimal model for a navigational…
View article: Layer topology of smectic grain boundaries
Layer topology of smectic grain boundaries Open
Grain boundaries in extremely confined colloidal smectics possess a topological fine structure with coexisting nematic and tetratic symmetry of the director field. An alternative way to approach the problem of smectic topology is via the l…
View article: Biaxial nematic order in fundamental measure theory
Biaxial nematic order in fundamental measure theory Open
Liquid crystals consisting of biaxial particles can exhibit a much richer phase behavior than their uniaxial counterparts. Usually, one has to rely on simulation results to understand the phase diagram of these systems, since very few anal…
View article: Emergent memory from tapping collisions in active granular matter
Emergent memory from tapping collisions in active granular matter Open
In an equilibrium thermal environment, random elastic collisions between background particles and a tracer establish the picture of Brownian motion fulfilling the celebrated Einstein relation between diffusivity and mobility. In nature, en…
View article: Colloidal smectics in button-like confinements: Experiment and theory
Colloidal smectics in button-like confinements: Experiment and theory Open
Liquid crystals can self-organize into a layered smectic phase. While the smectic layers are typically straight, forming a lamellar pattern in bulk, external confinement may drastically distort the layers due to the boundary conditions imp…
View article: Network topology of interlocked chiral particles
Network topology of interlocked chiral particles Open
Self-assembly of chiral particles with an L-shape is explored by Monte-Carlo computer simulations in two spatial dimensions. For sufficiently high packing densities in confinement, a carpet-like texture emerges due to the interlocking of L…
View article: Foundation of classical dynamical density functional theory: uniqueness of time-dependent density-potential mappings
Foundation of classical dynamical density functional theory: uniqueness of time-dependent density-potential mappings Open
When can we map a classical density profile to an external potential? In equilibrium, without time dependence, the one-body density is known to specify the external potential that is applied to the many-body system. This mapping from a den…
View article: Dynamics of active particles with translational and rotational inertia
Dynamics of active particles with translational and rotational inertia Open
Inertial effects affecting both the translational and rotational dynamics are inherent to a broad range of active systems at the macroscopic scale. Thus, there is a pivotal need for proper models in the framework of active matter to correc…
View article: Statistics of carrier-cargo complexes
Statistics of carrier-cargo complexes Open
We explore the statistics of assembling soft-matter building blocks to investigate the uptake and encapsulation of cargo particles by carriers engulfing their load. While the such carrier-cargo complexes are important for many applications…
View article: Colloidal smectics in button-like confinements: experiment and theory
Colloidal smectics in button-like confinements: experiment and theory Open
Liquid crystals can self-organize into a layered smectic phase. While the smectic layers are typically straight forming a lamellar pattern in bulk, external confinement may drastically distort the layers due to the boundary conditions impo…
View article: Network topology of interlocked chiral particles
Network topology of interlocked chiral particles Open
Self-assembly of chiral particles with an L-shape is explored by Monte-Carlo computer simulations in two spatial dimensions. For sufficiently high packing densities in confinement, a carpet-like texture emerges due to the interlocking of L…
View article: Density functional approach to elastic properties of three-dimensional dipole-spring models for magnetic gels
Density functional approach to elastic properties of three-dimensional dipole-spring models for magnetic gels Open
Magnetic gels are composite materials consisting of a polymer matrix and embedded magnetic particles. Those are mechanically coupled to each other, giving rise to the magnetostrictive effects as well as to a controllable overall elasticity…
View article: Dynamics of active particles with translational and rotational inertia
Dynamics of active particles with translational and rotational inertia Open
Inertial effects affecting both the translational and rotational dynamics are inherent to a broad range of active systems at the macroscopic scale. Thus, there is a pivotal need for proper models in the framework of active matter to correc…
View article: Collective mechano-response dynamically tunes cell-size distributions in growing bacterial colonies
Collective mechano-response dynamically tunes cell-size distributions in growing bacterial colonies Open
Mechanical stresses stemming from environmental factors are a key determinant of cellular behavior and physiology. Yet, the role of self-induced biomechanical stresses in growing bacterial colonies has remained largely unexplored. Here, we…
View article: Density functional approach to elastic properties of three-dimensional dipole-spring models for magnetic gels
Density functional approach to elastic properties of three-dimensional dipole-spring models for magnetic gels Open
Magnetic gels are composite materials, consisting of a polymer matrix and embedded magnetic particles. Those are mechanically coupled to each other, giving rise to the magnetostrictive effects as well as to a controllable overall elasticit…
View article: Active particles driven by competing spatially dependent self-propulsion and external force
Active particles driven by competing spatially dependent self-propulsion and external force Open
We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles. We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim-vel…
View article: Geometric criteria for the absence of effective many-body interactions in nonadditive hard particle mixtures
Geometric criteria for the absence of effective many-body interactions in nonadditive hard particle mixtures Open
We consider a mixture of small and big classical particles in arbitrary spatial dimensions interacting via hard-body potentials with non-additive excluded-volume interactions. In particular, we focus on variants of the Asakura--Oosawa (AO)…
View article: Tunable Brownian magneto heat pump
Tunable Brownian magneto heat pump Open
We propose a mesoscopic Brownian magneto heat pump made of a single charged Brownian particle that is steered by an external magnetic field. The particle is subjected to two thermal noises from two different heat sources. When confined, th…
View article: Report on scipost_202203_00001v1
Report on scipost_202203_00001v1 Open
We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles.We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim velo…
View article: Report on scipost_202203_00001v1
Report on scipost_202203_00001v1 Open
We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles.We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim velo…
View article: Report on scipost_202203_00001v1
Report on scipost_202203_00001v1 Open
We investigate how the competing presence of a nonuniform motility landscape and an external confining field affects the properties of active particles.We employ the active Ornstein-Uhlenbeck particle (AOUP) model with a periodic swim velo…