Abstract：
     Both decoherence and operation of a microscopic system involve  interaction with a macroscopic system. It may be questioned whether  the traditional approach of the master equation and the modern quantum  error correction introduce the noise and irreversibility before their  time. The recent efforts in an all quantum treatment of decoherence  and of noise in operation by my group will be presented for  discussion. Two key results may be put in terms of a Maxwell angel and  a quantum centrifugal governor.

Profile：
     Prof. Sham got his bachelor’s degree in Mathematics from Imperial College London and Ph. D degree from University of Cambridge, UK. He is currently distinguished professor of physics as well as adjunct professor in Computer & Electrical Engineering of UCSD. As a theoretical physicist who specialized in condensed matter physics, Prof. Sham worked with 1988 Nobel Laureate in Chemistry, Prof. Walter Kohn and his colleagues in developing the classical Kohn-Sham equation.  Prof. Sham was elected a member of the US National Academy of Sciences and of the American Physical Society and Optical Society of America in recognition of his Pioneering work in density functional theory, semiconductor heterostructures, the optical properties of crystalline solid, and solid state quantum information processing.