Nonlinear physics is a catch-all term for the study of the dynamics of driven, open, non-equilibrium systems. Our group is mainly concerned with the phenomenon of pattern formation. When a nonlinear, dissipative system ( that is, one with friction ) is driven hard enough, it will often undergo a symmetry-breaking instability which takes it to a regular pattern state. The pattern is a dynamical state sustained by the driving forces which can have a high degree of periodic order and symmetry, even while it is producing and exporting entropy. Patterns are simple examples of emergent, self-organized structures which exist under non-equilibrium conditions. Surprisingly ordered nonequilibrium patterns are found in many different places in nature, including convection cells in fluids, spirals in oscillatory chemical reactions, ripples on blown sand, and in many biological and geological processes.

You can get more information on our experiments in the following areas:

Convection in chemical waves	Electroconvection in suspended smectic films	Faraday patterns in surface waves
Crack patterns and columnar joints	Chladni patterns in vibrated plates	Fingering in turbidity flows
Rayleigh-Bénard and Bénard-Marangoni convection	Granular physics: segregation and washboard road	The physics of everyday life

• Appearances on the Discovery Channel: see the everyday life page.
• Mastering the mixer: The frustrating physics of cake mix and concrete, in Science News, July 2003.
• You, too, can grow ice-cube spikes in your own freezer!, by April Holladay, USA Today, Oct. 2005.
• Hanging pretty: how does the drip, drip, drip of water transform a cave into an art gallery? Article about stalactites that also mentions ripples on icicles, by Stu Hutson, New Scientist 190.2550 (May 6, 2006): p44(4).
• Why do ice cubes grow spikes? in Scientific American, April 2007.
• Columnar Jointing Gives Rise to Natural Wonders, in APS News, May 2007. See this press release for more information.
• Cambridge and Lyon washboard road experiments. Papers:[1][2]. Movies: [long view][onset][developed][stroboscopic plow].
  • A summary page on the experiment, by Nicolas Taberlet.
  • Road Bumps: Why dirt roads develop a washboard surface, in Science News, August 2007.
  • Comment une piste devient de la tôle ondulée, in Le Monde (in french), August 2007.
  • Road bump rage, in Blogcritics magazine, August 2007.
  • Physicists hit the rippled road in Physics World magazine, August 2007.
  • Ever wonder why dirt roads turn washboard rough? in ITWire magazine, Australia, August 2007.
  • Washboard Road Ahead: 5 MPH Colorado Confidential blog, by Dan Whipple.
  • Washboarding entry in Wikipedia.
  • Bumpy roads got you rattled?, The Bulletin, Bend Oregon.
• Corn starch solves 'Giant' mystery, The National Post, January 5th, 2009. See also the press release about our PNAS paper.
• Mystery of Causeway stones unlocked in the lab, from the Belfast Telegraph, January 5, 2009.

The Experimental Nonlinear Physics Group, Dept. of Physics, University of Toronto,
60 St. George St. Toronto, Ontario, Canada, M5S 1A7. Phone (416) 978 - 6810.