He is currently a Professor in the Department of Electrical and Systems Engineering and the Director of the Center for Robotics and Automation at Washington University. He also is the director of the Center for Quantum Information Science and Technology at Tsinghua University. An active member of the IEEE Robotics and Automation Society, Dr. Tarn served as the President of the IEEE Robotics and Automation Society, 1992-1993, the Director of the IEEE Division X (Systems and Control), 1995-1996, and a member of the IEEE Board of Directors, 1995-1996. He is the first recipient of the Nakamura Prize at the 10th Anniversary of IROS in Grenoble, France, 1997, the recipient of the prestigious Joseph F. Engelberger Award of the Robotic Industries Association in 1999, the Auto Soft Lifetime Achievement Award in 2000, the Pioneer in Robotics and Automation Award in 2003 from the IEEE Robotics and Automation Society, and the George Saridis Leadership Award from the IEEE Robotics and Automation Society in 2009. He was featured in the Special Report on Engineering of the 1998 Best Graduate School issue of US News and World Report and his recent research accomplishments were reported in the Washington Times, Washington D.C., the Financial Times, London, Le Monde, Paris, and the Chicago Sun-Times. Dr. Tarn is a Fellow of IEEE and an IFAC Fellow.
Decoherence, which is caused due to the interaction of a quantum system with its environment plagues all quantum systems and leads to the loss of quantum properties that are vital for quantum computation and quantum information processing. Superficially, this problem appears to be the disturbance decoupling problem in classical control theory. In this talk first we briefly review recent advances in Quantum Control. Then we propose a novel strategy using techniques from geometric systems theory to completely eliminate decoherence and also provide conditions under which it can be done so. A novel construction employing an auxiliary system, the bait, which is instrumental to decoupling the system from the environment, is presented. This literally corresponds to the Internal Model Principle for Quantum Mechanical Systems which is quite different from the classical theory due to the quantum nature of the system. Almost all the earlier work on decoherence control employ density matrix and stochastic master equations to analyze the problem. Our approach to decoherence control involves the bilinear input affine model of quantum control system which lends itself to various techniques from classical control theory, but with non-trivial modifications to the quantum regime. This approach yields interesting results on open loop decouplability and Decoherence Free Subspaces (DFS). The results are also shown to be superior to the ones obtained via master equations. Finally, a methodology to synthesize feedback parameters itself is given, that technology permitting, could be implemented for practical 2-qubit systems performing decoherence free Quantum Computing. Open problems and future directions in quantum control also will be discussed.
