Scientific Background
Scientific advances in the 20th Century .
The
Frontier Science of Emergent Materials
As
we stand at the edge of the 21st
century, equally bold new developments are now possible, and revolutions
ahead will almost certainly depend on a new fabric of understanding. In addition to the conventional frontiers of
the very small and very large, the scientific community is increasingly aware
of a new frontier- that of emergent and collective behavior. As matter becomes more complex, as one goes
from the simplest elements, to ever more complex crystals, new kinds of
behavior, often wholy unexpected, emerge from the collective interaction of its
constituents. It is this emergent behavior that drives the crystallization of
matter, the formation of magnets, superconductors, the folding of proteins and
ultimately, the organizing principles on which life itself depends. The
discoveries of the last twenty years- and the ever closer convergence between
biology and physics beckon us to develop
principles that govern the emergent, collective behavior of complex systems. The study of the new principles that govern
the collective behavior of matter is a frontier in its own right, complimentary
to those of particle physics and cosmology.
Some
examples of areas of study in the field of condensed matter physics are shown
above. The first example, that of colossal magnetoresistance (CMR), is a good
example of how quite often, deep intellectual problems- here the problem of
understanding why a material can be driven insulating by a magnetic field can
also have important real-world applications, such as the development of new
types of magnetic memory device. The
second two examples emphasize some of the deep unsolved problems in collective
matter behavior: the unsolved problem of the collective motion in avalanches-
important for understanding granular matter; the physics of water-drop
formation, which may be important for
the understanding of star formation, and lastly, the mysterious linear
temperature dependence of the resistitivity in the normal state of high
temperature superconductors, whereby linear resistivity continues from liquid
Helium temperatures, up to the melting point of the material. The metallic state which forms in these
materials is thought by some, to be driven by an underlying state of quantum criticality (see above).
