Fundamental limits on control of open quantum systems with applications to biomolecular NMR spectroscopy Navin Khaneja , Assistant Professor of Electrical Engineering, Division of Applied Sciences, Harvard

Relaxation in open quantum systems results in loss of signal and information and limits the range of applications. In NMR spectroscopy of macromolecules, large transverse relaxation rates of spins lead to poor sensitivity in experiments and long measurement times. In this talk, I will present our work on optimal control of coupled spin systems in the presence of relaxation. In particular, I will derive fundamental limits on the maximum coherence and polarization that can be transferred between coupled spins under decoherence. I will show how the methodology of control theory can be developed to find relaxation optimized pulse sequences for manipulating dynamics of networks of coupled spins. Experiments have shown that these relaxation optimized methods result in significant enhancement of sensitivity of multidimensional NMR experiments. I will present our recent work on adapting these relaxation optimized NMR experiments for structural studies of very large proteins in solution.