Research

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.

T. Axmann and M. Schmiedeberg and for anisotropic systems in cooperation with A. Härtel (Freiburg) 

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)

Supported within the Emmy-Noether-Program of the DFG (Project number 191633488) and by a grant of the DFG (Project number 531383052).

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)

Jamming and 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.

T. Axmann, 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 (Project number 262587878).

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 (Project Number 374790102).

Colloids with complex interactions or on incommensurate substrates

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. Furthermore, we have studied the ordering, growth, and complex structures on incommensurate substrates.

M. Schmiedeberg  in cooperation with E.C. Oğuz (Peking) and with the group of H. Löwen (Düsseldorf)

Selected Publication:
E.C. Oğuz et al., Phys. Rev. E 98, 052601 (2018)
T. Neuhaus et al., EPJ ST 223, 373 (2014);
T. Neuhaus et al., PRL 110, 118301 (2013)

Supported within the Emmy-Noether-Program (Project number 191633488) and the Priority Program SPP 1296 of the DFG.

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 (Project number 191633488).

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), and H. Löwen (Düsseldorf)

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)

Supported within the Emmy-Noether-Program (Project number 191633488) and by a grant of the DFG (Project Number 541211648).

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), E.C. Oğuz↗ (Peking), C. Bechinger (Konstanz), H. Stark (TU Berlin), and J. Roth (Stuttgart)

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)

Supported within the Emmy-Noether-Program (Project number 191633488) and by a grant of the DFG (Project Number 541211648).

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 and M. Schmiedeberg

Complex self-organized structures in soft matter or biological systems supported by artificial intelligence

By using neural network, we want to support the growth and predict the formation of complex colloidal structures.

M. Gimperlein, J. Buba , and M. Schmiedeberg

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)

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;
D. Arold and M. Schmiedeberg, Eur. Phys. J. E, 43, 47 (2020)

Motility and Crowding of bacteria

Twitching motility of Neisseria gonorrhoeae.

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)

New type of seminar and Physicists‘ Tournaments

I have 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)