Condensed Matter Seminar Announcement Prof. Joel Moore UC Berkekey "Frontiers in spin: frustration, transport, and entanglement" Date: Thursday, April 28, 2005 416 Phy/Geo Time: 4:10 pm. Abstract: This talk reviews three areas in which new materials and techniques have raised important questions for the theory of interacting spins. Magnetic materials in which exchange interactions are "frustrated" by lattice geometry show many complex ordered states separated by quantum phase transitions. The kagome spin-1 antiferromagnet is discussed as an example in which a solvable critical line separates two phases with unusual order and dynamics. We then discuss an optical transient grating experiment on spin transport, and in particular how spin currents and "spin drag" differ from their charge analogues; recent experiments at Berkeley open a new window into spatially resolved picosecond spin dynamics. The last part explains how the same quantum critical points studied in condensed matter physics are of special interest for quantum information theory. At critical points, spin systems generate long-ranged entanglement from short-ranged interaction, and the degree of entanglement is a quantitative measure of critical entropy.

E-Mail: jemoore@socrates.berkeley.edu
Web Page: http://socrates.berkeley.edu/~jemoore/