Jonathan Kollmer

Former Postdoc

Jonathan Kollmer is a postdoctoral research scholar at NC State University. He graduated with a physics diploma from the University of Bayreuth, Germany in 2009. He received his doctorate in 2015 from Friedrich-Alexander-Universität Erlangen Nürnberg, Germany working on dynamic granular systems. He moved to North Carolina to join NC State in 2016. His current research involves force networks in static granular systems. He also has a strong research interest in granular systems under low gravity and has done microgravity experiments on multiple parabolic flights and the Bremen drop tower.

Update from May 2018: Find Jonathan back in Germany, doing more astrophysics-with-grains in Duisberg!

PeGS

Photoelastic Grain Solver (PeGS)

Jonathan is the author and maintainer of the PeGS open source project. PeGS is a tool to extract vectorial contact forces from images of photoelastic particles. PeGS is described in detail in the article “Photoelastcic force measurements in granular materials” and the source code is available on GitHub .

Publications

Spongelike Rigid Structures in Frictional Granular Packings
Liu, K., Kollmer, J. E., Daniels, K. E., Schwarz, J. M., & Henkes, S. (2021), Physical Review Letters, 126(7). https://doi.org/10.1103/PhysRevLett.126.088002
Migrating Shear Bands in Shaken Granular Matter
Kollmer, J. E., Shreve, T., Claussen, J., Gerth, S., Salamon, M., Uhlmann, N., … Poeschel, T. (2020), PHYSICAL REVIEW LETTERS, 125(4). https://doi.org/10.1103/PhysRevLett.125.048001
Rigidity percolation control of the brittle-ductile transition in disordered networks
Berthier, E., Kollmer, J. E., Henkes, S. E., Liu, K., Schwarz, J. M., & Daniels, K. E. (2019), Physical Review Materials, 3(7). https://doi.org/10.1103/PhysRevMaterials.3.075602
Photoelastic force measurements in granular materials
Daniels, K. E., Kollmer, J. E., & Puckett, J. G. (2017), Review of Scientific Instruments, 88(5). https://doi.org/10.1063/1.4983049

View all publications via NC State Libraries

Jonathan Kollmer