Nanobot swimmer.
Recipe for the ultimate extreme winter sport: Set nanometer-sized robots swimming in a pool chilled to near absolute zero.
Nanobot swim sprints might not make the Olympics, but in theory they're possible, say mathematical physicists. Joseph Avron, Boris Gutkin, and a colleague at the Technion-Israel Institute of Technology in Haifa, Israel, had previously studied larger robots swimming in a viscous fluid and decided to see what would happen at the nanoscale. They imagined robots consisting of spheres and rods capable of changing sizes and lengths in rhythmic patterns, in a rough analogy to swimming strokes, immersed in a supercold fluid of particles called fermions, which are described by quantum waves. Wriggling in certain ways, the robots transmit waves of fermions in one direction, pushing themselves in the other. With each "stroke," a swimmer moves a distance equal to a multiple of half the typical wavelength of the fermions, the researchers will report in an upcoming issue of Physical Review Letters. The swimmer also can move without losing energy.
The analysis may not be practical, but it was conceptually appealing, Avron says: "This is the kind of license a theorist can have." Leonid Levitov, a theoretical physicist at the Massachusetts Institute of Technology in Cambridge, agrees: "[The result] being beautiful is reason enough for doing the work."
CREDIT: AVRON ET AL., NEW J. PHYS., 7 234 (2005)
