Research Topics

Systems in Non-Equilibrium and Biology, Jamming, Crowding, Glassy Dynamics, and Gels:

Breakdown of dynamics Upon increase of the density or a decrease of the temperature, the dynamics in many systems might slow down dramatically (not only in soft matter systems). We want to understand this breakdown of dynamics in various systems including particulate model systems, but also in more realistic soft materials like colloidal suspensions, gels, and active or living systems. We explore possible links between structure and dynamics, the connection between the slowdown of soft and hard colloids, and its relation to the jamming or crowding transition. Selected Publications: M. Maiti et al., J. of Phys.: Cond. Matter 31, 165101 (2019)↗, M. Schmiedeberg, Phys. Rev. E 87, 052310 (2013)↗, M. Schmiedeberg et al., EPL 96, 36010 (2011)↗, T.K. Haxton et al., Phys. Rev. E 83, 031503 (2011)↗

Gel formation The slowdown of dynamics during gelation in colloid-polymer mixtures is attended by the formation of directed chains of colloids. This structural transition corresponds to a directed percolation transition. We are interested in the formation and ageing dynamics of such gel network structures. M. Gimperlein↗ and M. Schmiedeberg↗ in cooperation with the group of S.U. Egelhaaf↗ (Düsseldorf) Selected Publications: M. Kohl, R.F. Capellmann, M. Laurati, S.U. Egelhaaf, and M. Schmiedeberg, Nature Comm. 7, 11817 (2016)↗; M. Kohl and M. Schmiedeberg, EPJ E 40, 71 (2017)↗

Exploring the energy landscape of non-equilibrium transitions We explore non-equilibrium transitions like thermal jamming or the clustering transition by exploring the energy landscape of passive or active soft particulate systems. We want to extend these studies to other non-equilibrium or biological systems. M. Gimperlein↗ and M. Schmiedeberg↗ in cooperation with M. Maiti↗ (Münster) Selected Publications: M. Maiti and M. Schmiedeberg, Scientific Reports 8, 1837 (2018)↗; L. Milz and M. Schmiedeberg, Phys. Rev. E 88, 062308 (2013)↗; M. Maiti et al., J. of Phys.: Cond. Matter 31, 165101 (2019)↗; M. Maiti et al., Eur. Phys. J. E 42, 38 (2019)↗ Supported by a grant of the DFG (Schm 2657/3).

Structure and glassy dynamics close to a wall Due to the broken anisotropy, studies of a hard sphere system close to a wall reveal interesting insights to cage breaking and glassy dynamics. M. Schmiedeberg↗ in cooperation with A. Härtel↗ (Freiburg) Selected Publications: A. Härtel et al., Phys. Rev. E 92, 042310 (2015)↗; M. Kohl et al., J. of Phys.: Cond. Mat. 28, 505001 (2016)↗ Supported within the Emmy-Noether-Program of the DFG (Schm 2657/2).

Complex Colloidal Structures:

Complex structures obtained with patchy colloids We are interested how preferred binding angles in the case of patchy colloids influence the resulting self-assembled structures. A phase field crystal model is developed for a theoretical description. R. Weigel↗ and M. Schmiedeberg↗ Selected Publication: R.F.B. Weigel, M. Schmiedeberg, Modelling Simul. Mater. Sci. Eng. 30, 074003 (2022)↗; A. Gemeinhardt et al., EPJ E 41, 126 (2018)↗; A. Gemeinhardt et al., EPL 126, 38001 (2019)↗ Supported by a grant of the DFG (Schm 2657/4).

Phases in colloid-polymer mixtures We determine the complex phase behavior of charged colloidal particles that are surrounded by polymers. The resulting depletion attractions lead to a competition of different characteristic interaction length scales. M. Schmiedeberg↗ in cooperation with E.C. Oğuz↗ (Peking) Selected Publication: E.C. Oğuz et al., Phys. Rev. E 98, 052601 (2018)↗

Colloidal particles on incommensurate surfaces Ordering, growth, and complex structures on incommensurate substrates. M. Schmiedeberg↗ in cooperation with the group of H. Löwen↗ (Düsseldorf) Selected Publications: T. Neuhaus et al., EPJ ST 223, 373 (2014)↗; T. Neuhaus et al., PRL 110, 118301 (2013)↗ Supported within the Emmy-Noether-Program (Schm 2657/2) and the Priority Program SPP 1296↗ of the DFG.

Soft Quasicrystals:

Additional degrees of freedom in quasicrystals: Phasons Phonons are well-known modes in periodic crystals. In quasicrystals, which are aperiodic, additional degrees of freedom (correlated rearrangements termed phasons) occur and change their properties. M. Schmiedeberg↗ in cooperation with S.C. Kapfer↗ (FAU), J. Roth↗ (Stuttgart), and H. Stark↗ (TU Berlin) Selected Publications: J.A. Kromer et al., PRL 108, 218301 (2012)↗; J. Hielscher et al., J. of Phys.: Cond. Mat. 29, 094002 (2017)↗ Supported within the Emmy-Noether-Program of the DFG (Schm 2657/2).

Growth and melting of soft quasicrystals We investigate properties of intrinsic colloidal quasicrystals using a phase field crystal model or simulations. S. Wolf↗, R. Weigel↗, and M. Schmiedeberg↗ in cooperation with M. Engel↗ (technical faculty, Erlangen), C.V. Achim (Helsinki), H. Löwen↗ (Düsseldorf), and E.C. Oğuz↗ (Peking) Selected Publications: C.V. Achim et al., PRL 112, 255501 (2014)↗; M. Schmiedeberg et al., Phy. Rev. E 96, 012602 (2017)↗; M. Martinsons et al., J. of Phys.: Cond. Mat. 30, 255403 (2018)↗; A. Gemeinhardt et al., EPJ E 41, 126 (2018)↗

Statistical Properties of Quasicrystals We analyse statistical properties of quasicrystal, e.g., related to different LI-classes, the rank of crystals, or hyperuniformity. R. Weigel↗, and M. Schmiedeberg↗ in cooperation with A.S. Kraemer (Mexico City) and E.C. Oğuz↗ (Peking). Selected Publications: F. Rühle et al., EPJE 38, 54 (2015)↗, M. Schmiedeberg and H. Stark, Journal of Physics: Condensed Matter 24, 284101 (2012)↗, J. Mikhael et al., PNAS 107, 7214 (2010)↗

Quasicrystals composed of particles with preferred binding angles We want to understand how quasicrystals can be stabilized for particles that support only one one length scale but in addition have a preference for some binding angles (e.g., patchy colloids). R. Weigel↗ and M. Schmiedeberg↗ Selected Publications: R.F.B. Weigel, M. Schmiedeberg, Modelling Simul. Mater. Sci. Eng. 30, 074003 (2022)↗; A. Gemeinhardt et al., EPL 126, 38001 (2019)↗; A. Gemeinhardt et al., EPJ E 41, 126 (2018)↗ Supported by a grant of the DFG (Schm 2657/4).

Light-induced colloidal quasicrystals By employing the interference patterns of laser beams, a large varity of colloidal quasicrystals can be obtained and studied. M. Schmiedeberg↗ in cooperation with the groups of C. Bechinger↗ (Konstanz), H. Stark↗ (TU Berlin), and J. Roth↗ (Stuttgart) Selected Publications: F. Rühle et al., EPJ E 38, 54 (2015)↗; M. Schmiedeberg et al., EPJ E 32, 25 (2010)↗; J. Mikhael et al., PNAS 107, 7214 (2010)↗ Supported within the Emmy-Noether-Program of the DFG (Schm 2657/2).

Artificial Intelligence in Soft Matter and Biological Physics:

Characterizing gel structures with artificial intelligence By using neural network, we analyse the structure of gel networks. Specifically, we want to use the networks to determine the backbone of a similar idealized network and therefore extract its physical properties. M. Gimperlein↗, J. Buba↗ , A. Döner↗ and M. Schmiedeberg↗

Complex self-organized structures in soft matter or biological systems predicted by artificial intelligence By using neural network, we want to predict the complex structures that can be obtained for particles that interact with multiple characteristic length scales. M. Gimperlein↗ and M. Schmiedeberg↗

Detecting defects in quasicrystals with neural networks By using neural network, we analyse quasicrystalline patterns in order to detect and characterize defects. Note that detecting defects in quasicrystals by just looking on the patterns is extraordinary difficult even for specialists in the field. However, by using deep learning methods we are able to train neural networks such that they can identify and characterize the defects. Johannes Schöttner↗, A. Döner↗ and M. Schmiedeberg↗

Normal and Anomalous Diffusion, Dynamics in Biological Systems:

Browian particle on a rough surface Intermediate and asymptotic regimes of motion of a colloidal particle in a one-dimensional random laser potential. M. Schmiedeberg↗ in cooperation with the group of S.U. Egelhaaf↗ (Düsseldorf) Selected Publications: R.D.L. Hanes et al., Phys. Rev. E 88, 062133 (2013)↗; R.D.L. Hanes et al., Soft Matter, 8, 2714 (2012)↗

Continuous-Time Random Walks We study and compare different Lévy-Walk and Lévy-Flight models. M. Schmiedeberg↗ in cooperation with the group of V.Yu. Zaburdaev↗ Selected Publications: D. Froemberg et al., Phys. Rev. E 91, 022131 (2015)↗; M. Schmiedeberg et al., J. Stat. Mech. P12020 (2009)↗; V.Yu. Zaburdaev et al., Phys. Rev. E 78, 011119 (2008)↗

Biophysics and Active Particles:

Phase field crystal models for biological systems We are interested in pattern formation processes in systems consisting of living "particles". We develop and study phase field crystal models for their description. D. Arold↗ and M. Schmiedeberg↗ Publications: D. Arold and M. Schmiedeberg, J. of Phys.: Condensed Matter, 32 315403↗; Eur. Phys. J. E, 43, 47 (2020)↗

Motility and Crowding of bacteria Twitching motility of Neisseria gonorrhoeae. L. Self↗ and M. Schmiedeberg↗ in cooperation with V.Yu. Zaburdaev↗ (biology department, Erlangen) and other coworkers Publication: V.Yu. Zaburdaev et al., Biophysical Journal 107, 1523 (2014)↗

Didactics and Physics Competitions:

New type of seminar and Physicists' Tournaments I started a new type of seminar that deals with the problems of the German and International Physicists' Tournaments↗ where the students do their research on the problems of this tournament. Furthermore, I am involved as juror in the German Young Physicists' Tournament and in drafting problems for the DOPPLERS and PLANCKS competitions. M. Schmiedeberg↗ in cooperation with A. Fösel↗ (didactics, Erlangen) Publications: J. Bley, A. Pietz, A. Fösel, M. Schmiedeberg, S. Heusler, and A. Pusch, European Journal of Physics 43, 014001 (2022)↗ , S. Michalke, A. Foesel, and M. Schmiedeberg, European Journal of Physics 41, 054001 (2020)↗ see also: FAUltiere für die Physik↗