Perhaps the deepest mystery in physics today is the origin of the accelerating expansion of the universe. Professors Khoury and Trodden work, among other things, on the possibility that it is due to a dark sector with new light degrees of freedom. Screening mechanisms, such as chameleon and symmetron, may explain why such scalars, if light, have escaped detection.
Nanoscale Electronic Nose
Prof. Charlie Johnson's group at Penn have coupled olfactory receptor proteins from mice to carbon nanotubes to create a prototype electronic nose. Olfactory receptors are embedded in nanodiscs that mimic the environment of the olfactory cell membrane. Odorant molecules bind to the receptor, which produces an electrical response in the carbon nanotube (gray cylinder).
MRSEC Research at Penn
The P&A department plays a large role in the Laboratory for Research on the Structure of Matter (LRSM). One focus of LRSM research between faculty from different departments and schools is soft matter and how it conforms, assembles, and reconfigures in response to the geometry and chemistry of bounding surfaces and interfaces.
Proteins on Carbon Nanotubes
The image shows an example of peptides that assemble into a tubular structure surrouding single-walled carbon nanotubes. The geometrically defined, virus-like coating created by these peptides converts the smooth surfaces of carbon nanotubes into highly textured assemblies with long-scale order, capable of directing the assembly of gold nanoparticles into helical arrays along the nanotube axis.
Prof. Vijay Balasubramanian's research includes studies of structural and functional organization of the retina with multi-electrode arrays that record retinal ganglion cells. He also studies computational principles that underlie the organization of circuits in the early visual system.
This work, "Lassoing saddle splay and the
geometrical control of topological defects," was done with postdoctoral
fellow Max Lavrentovich. The two work with Professors Randy Kamien
(Physics and Astronomy) and Kate Stebe (Chemical and Biomolecular Engineering).