Friday, May 27, 2011
2:00pm (110 INSCC)
Title: Investigations of Microscopic Chaos in Dipolar-Coupled Nuclear Spin Systems
In solid-state NMR, transverse nuclear spin relaxation is one of the more important sources of microscopic information. Although the calculation of the NMR absorption lineshape in a solid is a well-defined problem, a general solution continues to evade the best efforts of researchers despite the application of an impressive array of approximation schemes to the problem. practically, one would like to be able to explain/understand the characteristic features of transverse decays as reflecting details of the internal structure and interactions, while from a theoretical point of view the interest is in the possibility of treating a ‘relatively simple’ many-body dissipative system.
Recently, a new theoretical description of the relaxation of quantum many-body systems has emerged which relies on the notion that microscopic chaos plays an integral role in the dynamical evolution of such systems. I will explore the implications of this chaos-related theory and its predictions when applied to the NMR transverse magnetization decay problem. Finally, I will show the results of a wide array of experiments that were motivated by these predictions and designed specifically to test their consistency with measured signals.