FG Statistische Physik weicher Materie und biologischer Systeme

7 Items

Recent Submissions
Dissipative systems with nonlocal delayed feedback control

Grawitter, Josua ; van Buel, Reinier ; Schaaf, Christian ; Stark, Holger (2018-11-07)

We present a linear model, which mimics the response of a spatially extended dissipative medium to a distant perturbation, and investigate its dynamics under delayed feedback control. The time a perturbation needs to propagate to a measurement point is captured by an inherent delay time (or latency). A detailed linear stability analysis demonstrates that a nonzero system delay acts to destabili...

Simulating the complex cell design of Trypanosoma brucei and its motility

Alizadehrad, Davod ; Krüger, Timothy ; Engstler, Markus ; Stark, Holger (2015)

The flagellate Trypanosoma brucei, which causes the sleeping sickness when infecting a mammalian host, goes through an intricate life cycle. It has a rather complex propulsion mechanism and swims in diverse microenvironments. These continuously exert selective pressure, to which the trypanosome adjusts with its architecture and behavior. As a result, the trypanosome assumes a diversity of compl...

Gravity-induced dynamics of a squirmer microswimmer in wall proximity

Rühle, Felix ; Blaschke, Johannes ; Kuhr, Jan-Timm ; Stark, Holger (2018-02-07)

We perform hydrodynamic simulations using the method of multi-particle collision dynamics and a theoretical analysis to study a single squirmer microswimmer at high Péclet number, which moves in a low Reynolds number fluid and under gravity. The relevant parameters are the ratio α of swimming to bulk sedimentation velocity and the squirmer type β. The combination of self-propulsion, gravitation...

Physical minimal models of amoeboid cell motility

Kulawiak, Dirk Alexander (2017)

Cell locomotion plays an important role in many biological processes such as the immune system, embryonic development, or cancer metastasis. In these examples, cells interact with their environments or coordinate their movements with other cells, creating collective behavior. In this thesis, we utilize minimal modeling to investigate single and collective cell motility in three different settin...

Dynamics of a bacterial flagellum under reverse rotation

Adhyapak, Tapan Chandra ; Stark, Holger (2016)

To initiate tumbling of an E. coli, one of the helical flagella reverses its sense of rotation. It then transforms from its normal form first to the transient semicoiled state and subsequently to the curly-I state. The dynamics of polymorphism is effectively modeled by describing flagellar elasticity through an extended Kirchhoff free energy. However, the complete landscape of the free energy r...

Phase separation and coexistence of hydrodynamically interacting microswimmers

Blaschke, Johannes ; Maurer, Maurice ; Menon, Karthik ; Zöttl, Andreas ; Stark, Holger (2016)

A striking feature of the collective behavior of spherical microswimmers is that for sufficiently strong self-propulsion they phase-separate into a dense cluster coexisting with a low-density disordered surrounding. Extending our previous work, we use the squirmer as a model swimmer and the particle-based simulation method of multi-particle collision dynamics to explore the influence of hydrody...

Taylor line swimming in microchannels and cubic lattices of obstacles

Münch, Jan L. ; Alizadehrad, Davod ; Babu, Sujin B. ; Stark, Holger (2016)

Microorganisms naturally move in microstructured fluids. Using the simulation method of multi-particle collision dynamics, we study in two dimensions an undulatory Taylor line swimming in a microchannel and in a cubic lattice of obstacles, which represent simple forms of a microstructured environment. In the microchannel the Taylor line swims at an acute angle along a channel wall with a clearl...