Organizational Unit:
School of Physics

Research Organization Registry ID
Description
Previous Names
Parent Organization
Parent Organization
Organizational Unit
Includes Organization(s)
Organizational Unit

Publication Search Results

Now showing 1 - 3 of 3
  • Item
    The Neuromechanics of Insect Locomotion: How Cockroaches Run Fast and Stably Without (Much) Thought
    (Georgia Institute of Technology, 2013-03-11) Holmes, Philip
    I will describe several models for running insects, from an energy-conserving biped, through a muscle-actuated hexapod driven by a neural central pattern generator, to a reduced phaseoscillator model that captures the dynamics of unperturbed gaits and of impulsive perturbations. I will argue that both simple models and large simulations are necessary to understand biological systems. The models show that piecewise-holonomic constraints due to intermittent foot contacts confer asymptotic stability on the feedforward system, while leg force sensors modulate motor outputs to mitigate large perturbations. Phase response curves and coupling functions help explain reflexive feedback mechanisms. The talk will draw on joint work with Einat Fuchs, Robert Full, Raffaele Ghigliazza, Raghu Kukillaya, Josh Proctor, John Schmitt, and Justin Seipel. Research supported by NSF and the J. Insley Blair Pyne Fund of Princeton University.
  • Item
    God Does Play Dice: How Chaos Crafted the Kuiper Belt, Why Quantum Mechanics is Craps, and other Curmudgeonly Concepts
    (Georgia Institute of Technology, 2012-04-09) Farrelly, David
    Joseph Ford saw beauty in "Chaos" and the potential for ``villainous chaos" to be used in a constructive manner. His ideas have proved prescient. The talk will focus mainly on how chaotic dynamics may have played a key constructive -- rather than destructive -- role in shaping certain features of the Kuiper belt: in particular, the formation and properties of binary objects in the transneptunian part of the Solar System. Kuiper belt binaries stand out from other known binary objects in having a range of peculiar orbital and physical properties which may, actually, be the fingerprint of chaos in the primordial Kuiper belt. Understanding how these remote binaries formed may shed light on the formation and evolution of the Solar System itself.
  • Item
    Twistor Theory, Then and Now
    (Georgia Institute of Technology, 2009-03-25) Penrose, Roger
    Twistor theory is now over 45 years old. In December 1963, I proposed the initial ideas of this scheme, based on complex-number geometry, which presents an alternative perspective to that of standard 4-dimensional space-time, for the basic arena in which (quantum) physics takes place. Over the succeeding years, there were numerous intriguing developments. But many of these were primarily mathematical, and there was little interest expressed by the physics community. Things changed rather dramatically, in December 2003, when E.Witten produced a 99-page article initiating the subject of “twistor-string theory” this providing a novel approach to high-energy scattering processes. In this talk, I shall provide an account of the original geometrical and physical ideas, and also outline various recent developments, some of which may help our understandings of the seeming paradoxes of quantum mechanics.