Scientists have long-debated the microscopic origin of friction between macroscopic surfaces. A new experimental analysis finds that two metallic surfaces placed together spontaneously deform to create an Angstrom-sized bond. This bond then grows in size over about one minute to nanometer levels. These bonds account for the slip-stick friction observed as two metal surfaces slide over each other. The measurements of this microscopic phenomenon were performed with a fiber-optic cantilever surface probe microscope that is sensitive to sub-nanoscale motions.
2) Ping-pong polymers Physical Review E (Print issue: March 2002)
In a low-tech experiment, researchers have simulated the behavior of complex molecules in solvents by putting a chain of plastic spheres in a bath of randomly moving balls that are often used as toys for pets. The random motion of the balls simulates the thermal jiggling of molecules known as Brownian motion. With a video camera and simple image recognition, the folding and unfolding of the molecule and other molecular processes can be simulated and analyzed. The results are applicable to many areas of polymer and statistical physics.
Journal article: http://link.aps.org/abstract/PRE/v65/e031306
3) Turning the superconductivity mechanism inside out bosons into fermions arXiv preprint server
Superconductors have their characteristic properties because of Cooper pairing a phenomenon in which pairs of interacting fermions (spin-1/2 particles such as electrons) join together in pairs and act as non-interacting bosons (spin-1 particles). At the most simplistic level, the two spin-1/2 particles add together to give spin-1. Therefore it is surprising that the reverse procedure can
Contact: David Harris
American Physical Society