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Monday, March 09, 2009

physics from control theory

One of the challenges I have been dealing with in my current position is trying to remain true to my scientist interests while working in a largely engineering environment. See e.g. here for some of my thoughts/struggles with science vs. engineering. Specifically, I had the feeling that a control theory methodology was killing the science outlook in my group.

Recently a colleague recommended an article on control theory in Review of Modern Physics:
(sorry, you need a subscription..) entitled "Feedback for physicists: a tutorial essay on control".
The author John Bechhoefer covers quite broad ground in this review article. I've just read a little so far, but a paragraph in the conclusion caught my eye:
What is perhaps most interesting to a physicist is the way new kinds of behavior arise from the structure of control loops. The tracking property of integral feedback comes from the structure of the feedback loop, not the nature of the individual elements. In this sense, it is a kind of "emergent phenomenon", but one that differs from the ones familiar in physics such as the soft modes and phase rigidity that accompany symmetry breaking phase transitions. Thus, engineering provides an alternate set of archetypes for emergent phenomena... (p. 832)
What Bechhoefer is pointing out is a way to go beyond control theory as purely an attempt to control, but instead to look for examples of control mechanisms in nature. He gives biology examples, and even suggests some quantum mechanics examples. Here is engineering giving back to science, at a conceptual level. Looks like the start of a more healthy collaboration!

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