[QIP-Sem] LIDS colloquium: Khaneja / Control of Spin Systems - Tues 4pm 32-141

[Isaac Chuang]

L I D S   C O L L O Q U I U M
LABORATORY FOR INFORMATION AND DECISION SYSTEMS
-----------------------------------------------

Control of Spin Systems

Navin Khaneja (Harvard University)

Tuesday, Sep 27, 2005
4:00-5:00 p.m.  32-141 

A short reception will follow on the 6th floor of the Dreyfoos Building.

Abstract

In this talk I will discuss some control problems that arise in
manipulation of coupled spin dynamics in NMR spectroscopy using radio
frequency pulses. In control and manipulation of quantum systems, the
system of interest is rarely isolated but interacts with its
environment. This leads to phenomenon of relaxation which in practice
results in signal loss and limits the range of applications. Finding
optimal ways to manipulate dynamics of coupled nuclear spins to
minimize relaxation losses is an important problem. I will present our
work on optimal pulse sequence design for minimizing relaxation losses
and improving the sensitivity of NMR experiments. Applications of
these optimal control methods to NMR spectroscopy of very large
proteins in solution will be discussed. These experiments involve
steering an ensemble of quantum systems, which show dispersion in the
parameters that govern their dynamics. This gives rise to interesting
control problems of steering a continuum of dynamical systems with
different dynamics using the same control that can compensate for the
various dispersions. I will discuss our recent work on controllability
of quantum ensembles.

Biography:
----------

Navin Khaneja is associate professor of electrical engineering at
Harvard University. He received his PhD in applied mathematics from
Harvard in 2000. He works in the area of control theory and its
applications. His current research is in control of quantum systems
with a focus towards optimal pulse sequence design in high resolution
NMR spectroscopy in liquids and solids. He is a recipient of NSF
career award, Sloan fellowship and Bessel prize of the Humboldt
foundation.

For more information visit:
http://lids.mit.edu/EVENTS/abstracts/Khaneja.html
http://hrl.harvard.edu/~navin