Beller Research Group
for Soft Matter and Biological Physics#
We use theoretical approaches combining statistical physics, elasticity theory, and material geometry and topology, alongside computational approaches such as mesoscale relaxational methods, coarse-grained Brownian dynamics, and stochastic front propagation simulations. Spatial self-organization, complex geometries, and topological defects are recurring themes in our research. Much of our work is in close collaboration with experimentalists from Physics, Materials Science, and Chemical Engineering backgrounds.
Our current research areas include:#
Active matter with liquid crystalline order
How do emergent collective motions depend on material geometry, topology, and non-equilibrium force generation?
Self-assembly in ordered soft materials
How do material order, interfacial effects, and chirality determine spontaneous spatial patterning and structure formation in liquid crystals and soft solids?
Biological population genetics
What can statistical physics teach us about a population’s changing spatial structure and its evolutionary consequences?
Latest news#
May 19, 2026
Mateusz Ratman was awarded a Swiss Government Excellence Scholarship to fund his Ph.D. studies at the Ecole Polytechnique Fédérale de Lausanne (EPFL). Congratulations, Mateusz!
May 1, 2026
Cody Schimming has accepted a faculty position at UMass Boston's Department of Physics. He starts his independent research group in September, 2026. Congratulations, Cody!
April 30, 2026
Mateusz Ratman is a winner of the department's 2026 Donald E. Kerr Undergraduate Award. The Kerr Award, established in 1979, acknowledges outstanding graduating physics majors who have distinguished themselves through their performance in the classroom, their accomplishments in research, and their other positive contributions to the department. Congratulations, Mateusz!
March 4, 2026
In a paper published in Phys. Rev. E, we show that semiflexible filaments with chiral activity in the form of off-tangent self-propulsion can exhibit multistable dynamics including straight and curved trajectories.
November 3, 2025
With the group of Kevin Mitchell at UC Merced, we argue in a paper published in Soft Matter for introducing a new physical principle, dubbed "nematic locking", to the standard equations of nematic hydrodynamics in order to more accurately model microtubule-based active nematics.
August 29, 2025
Jane B.D.M. Garcia successfully defends her Ph.D. thesis, "Self-assembly of topological defects and nanoparticles in liquid crystals." Congratulations, Dr. Garcia!
August 27, 2025
Jimmy Gonzalez Nuñez successfully defends his Ph.D. thesis, "Evolution in expanding populations: from random landscapes to predictable patterns." Congratulations, Dr. Gonzalez! He will join Shenshen Wang's group at UCLA as a postdoc.
August 7, 2025
In collaboration with the Gharbi Lab at UMass Amherst, we demonstrate that the smectic-nematic liquid crystal phase transition coupled to a geometrically patterned confining boundaries offers a rich toolset for self-assembly of defects and nanoparticles. The paper is published in Nanoscale.
July 10, 2025
Jane Garcia wins a top poster prize at Liquid Crystals Gordon Research Conference. The award is a signed copy of Jonathan Selinger's new textbook. Congratulations, Jane!
June 30, 2025
We present evidence that off-tangent propulsion can explain the "time cholesteric" rotation of active nematic order in microtubule gliding assays, offering a new design principle for active matter of self-propelled filaments. The preprint is posted to arXiv.
June 30, 2025
Louise Head was awarded the 2025 Sam Edwards PhD Thesis Prize by the Institute of Physics. Congratulations, Louise!
June 26, 2025
With the group of Kevin Mitchell at UC Merced, we argue for introducing a new physical principle, dubbed "nematic locking", to the standard equations of nematic hydrodynamics in order to more accurately model microtubule-based active nematics. The preprint is posted to arXiv.
June 18, 2025
Using simulations of a meta-population model along with ideas from geometrical optics, we show that quenched-random structure in the environment significantly enhances the survival of deleterious mutants, in a paper published in the *Journal of the Royal Society Interface*.
April 17, 2025
In gliomas, a deadly type of brain tumor, cancer cells exhibit 3D quasi-long-range nematic order with disclination lines, as we and collaborators show in a preprint is posted to bioRxiv.
March 18, 2025
Jimmy Gonzalez Nuñez is a finalist for the GSNP Graduate Student Speaker Award at the 2025 American Physical Society Global Physics Summit. Congratulations, Jimmy!
March 13, 2025
We use simulations to establish the conditions and mechanism for self-propelled topological defects in active nematics to spontaneously following periodic braids rather than “topological chaos”, resulting in optimal fluid mixing. The preprint is posted to arXiv.
2024
December 2, 2024
Congratulations, Jimmy!
November 9, 2024
Mateusz Ratman gave his pedagogical presentation at the Fall 2024 Regional Undergraduate Math Research Conference hosted by Towson University.
October 9, 2024
Using simulations of a meta-population model along with ideas from geometrical optics, we show that quenched-random structure in the environment significantly enhances the survival of deleterious mutants. The preprint is posted to bioRxiv.
August 21, 2024
Congratulations, Dr. Athani! Her thesis is entitled "Emergent, Decaying, and Spinning Nematic Order in Collective Motion of Active Semiflexible Filaments."
August 13, 2024
In a paper published in Proceedings of the National Academy of Sciences, we show that when a biological population expands through a landscape with randomly distributed resources, the newly colonized area is dominated by a small fraction of geneaological lineages that followed paths of least time.
June 24, 2024
In a paper published in Physical Review Research, we find through agent-based simulations that long-range nematic order in "gliding assays" is transient rather than dynamically stable and requires the self-propelled filaments to glide over each other.
May 7, 2024
In a paper in Physical Review Materials, we show that wrapping a 2D crystalline sheet into a tube enables defects to interact in unusual sequences of topological transformations.
May 1, 2024
Louise arrives after earning her Ph.D. in the group of Prof. Tyler Shendruk at the University of Edinburgh. Welcome, Louise!
February 1, 2024
Chanania arrives after earning his Ph.D. in the group of Prof. Eytan Katzav at the Racah Institute of Physics. Welcome, Chanania!
January 8, 2024
Our article in Physical Review E shows that active nematic defect dynamics, which are normally chaotic, also admit a periodic orbit that maximizes the chaotic mixing of the active nematic fluid.
2023
October 19, 2023
In a new preprint posted to the arXiv, we show that when a biological population expands through a landscape with randomly distributed resources, the newly colonized area is dominated by a small fraction of geneaological lineages that followed paths of least time.
September 8, 2023
In a new preprint posted to the arXiv, we show that wrapping a 2D crystalline sheet into a tube enables defects to interact in unusual sequences of topological transformations.
September 7, 2023
This "News and Views" commentary in Nature Physics explores the impact on active matter research of a recent paper by Luca Giomi and collaborators on quantifying coexisting liquid crystal symmetries in cell monolayers.
August 21, 2023
In a new preprint posted to the arXiv, we show that active nematic defect dynamics, which are normally chaotic, also admit a periodic orbit that maximizes the chaotic mixing of the active nematic fluid.
August 17, 2023
Her poster titled “Symmetry and stability of orientationally ordered collective motions of self-propelled, semiflexible filaments” won second place for Best Poster Presentation at the program “Soft and Living Matter: from Fundamental Concepts to New Material Design” at the International Centre for Theoretical Sciences, Tata Institute of Fundamental Research.
July 18, 2023
June 5, 2023
In a new preprint posted to the arXiv, we reveal in numerical modeling how highly multistable patterns of liquid crystal defects can be generated using geometrically structured confinement and thermally controlled phase transitions, and how these patterns can be exploited to guide the self-assembly of nanoparticles.
June 5, 2023
In a new preprint posted to the arXiv, we find in agent-based simulations that long-range nematic order in "gliding assays" is transient rather than dynamically stable, and may require some motion in the third dimension.
April 21, 2023
Jimmy Gonzalez Nuñez was among a handful of speakers selected to present their research at the CUNY Graduate Center’s “Physics of Life: Students and Postdocs Edition” symposium. He gave a talk entitled “Environmental vs demographic noise in range expansions”.
2022
October 14, 2022
Jimmy Gonzalez Nunez on "the Role of Quenched Noise in the Evolution of Populations undergoing Range Expansions" with many cool simulations @NewtonInstitute pic.twitter.com/fr0WN2M1M5
— Marco Mauri (@MarcoMauri81) October 14, 2022
July 12, 2022
Active nematic dynamics in growing colonies of immotile bacteria may help slow the population's loss of genetic diversity --- paper published in Frontiers in Physics.
February 2, 2022
Crystalline sheets rolled up into tubes can be programmed with reconfigurable shapes through the placement and motion of defects in the crystalline lattice --- paper published in PNAS.
January 26, 2022
Jimmy Gonzalez Nuñez awarded a DBIO Shirley Chan Student Travel Grant for the APS March Meeting!
2021
December 21, 2021
Mobility of motor proteins enhances emergent active nematic dynamics in a microtubule gliding assay --- paper with Hirst, Dasbiswas, and Gopinathan groups (UC Merced) published in PNAS.
December 1, 2021
In nematic liquid crystals with low twist elastic constant, spontaneous chirality changes the orientations of rod-like colloidal particles embedded in the fluid --- paper with Yodh (Penn) and Collings (Swarthmore) groups published in Soft Matter.
October 11, 2021
A new kind of defect found in crystallization on a cylinder (or: "the frustration of meeting yourself on the other side") --- paper with Manoharan and Rycroft groups (Harvard University) published in ACS Applied Nano Materials.