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Center for Nonlinear Dynamics


Atom Optics, Biological Physics, Dynamics, Networks of Atoms and People.

Research Highlights:

Multiscale Bacterial Analysis: We examined a single strain (Paenibacillus dendritiformis T morphotype) to determine both the macroscopic growth of colonies and the microscopic bacterial motion within the colonies. Our multiscale measurements for a variety of growth conditions revealed that motion on the microscopic scale and colonial growth are largely independent. Instead, the growth of the colony is strongly affected by the availability of a surfactant that reduces surface tension.

Swarming Dynamics: We determine and relate the characteristic velocity, length, and time scales for bacterial motion in swarming colonies of Paenibacillus dendritiformis growing on semi-solid agar substrates. We find that various definitions of the correlation length all lead to length scales that are, surprisingly, essentially independent of the mean bacterial speed, while the correlation time is linearly proportional to the ratio of the correlation length to the mean speed.

Adhering biological membranes: The cell membrane is the interface where the cell meets the outside world. Recent research has shown that when model membranes adhere this can suppress thermally-driven spatial fluctuations and thus trigger the formation of heterogeneities at the adhesion site. We are currently developing a model system that will both allow us to explore the physics of this phenomenon more fully. For more information, talk with Matthew P., Matthew L., or Vernita.

Single Bond Formation Detection: We present a novel experimental method that solves two key problems in nondestructive mechanical studies of small biomolecules at the single-molecule level, namely the confirmation of single-molecule conditions and the discrimination against nonspecific binding. Our method brings quantitative mechanical single-molecule studies to the majority of proteins, paving the way for the investigation of a wide range of phenomena at the single-molecule level.

Cargo Transport in vivo: Inside living cells organelles and other cell constituents are constantly moving to reach where they are needed and establish internal cellular organization. The particulars of how opposite polarity motors work together and how their function is regulated in vivo remain for the most part enigmatic at many levels of detail.

Fracture of Rubber: The study of dynamic fracture has been a key component of material testing, especially airplanes, boats, and other vessels for which unstable cracks can be detrimental. We have studied two new features of the rupture of rubber. First, we carefully followed ruptures as they make a transition from subsonic to supersonic speeds. Second, we found that when rubber is stretched past a critical amount, ruptures stop propagating at all. This unexpected phenomenon is probably due to formation of crystals within the rubber.

Others: Chemical Instabilities and Optical Trapping of Biological Material

Alvarado, Jose No
José R Alvarado
Assistant Professor
Biophysics; Soft matter; Fluid mechanics; Active matter
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Ernst-Ludwig Florin
Associate Professor
Experimentalist; biophysics; cell physics; nonlinear dynamics
PMA 14.322
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Vernita Gordon
Associate Professor
Trull Centennial Professorship in Physics #1

Experimental biological physics; multicellular systems; the role of physics and spacial structure in developmental and evolutionary systems.
PMA 14.206
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Michael P Marder
Director Academic Center, Executive Director - UTeach
Mechanics of solids; Condensed matter theory
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Mark G Raizen
Professor, Professor of Pediatrics
Sid W. Richardson Foundation Regents Chair in Physics #2

Experimental atom optics
PMA 14.202
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Harry L Swinney
Professor Emeritus
Sid W. Richardson Foundation Regents Chair in Physics #3

Nonlinear dynamics; chaos; pattern formation; dynamics of internal gravity waves in the oceans and of growing bacterial colonies.