• Theoretical Condensed-Matter Physics
• Theoretical Elementary Particle Physics
• Astrophysics and General Relativity
• Experimental Elementary Particle Physics
• Accelerator Physics
• Experimental Condensed-Matter Physics
• Biological Physics
• Multidisciplinary Research
• Major Research Facilities
• Resources for Researchers

BA, 1977, Physics, Harvard University. PhD , 1981, Princeton University. Postdoctoral research associate, Cornell University, 1981-84. Postdoctoral research associate, Institute for Theoretical Physics, University of California at Santa Barbara, 1981-84. Assistant Professor, Physics, Cornell University, 1984-89. Associate Professor, Phsyics, Cornell University, 1989-95. Professor, Physics, Cornell University, 1995-present. Member, Fields of Applied Mathematics, 1996-present, Computational Biology, 2006-present, Computational Science and Engineering, 2006-present. Sloan Research Fellow, 1985. Presidential Young Investigator Award, 1985.

Research Areas
Materials science, including crackling noise and avalanches in magnetic systems, tweed in shape-memory alloys, accelerated simulations of surface growth, Arrhenius law for double jumps; glasses, including metallic glasses, low temperature glasses, slow relaxation, and scaling theories of the glass transition; disordered systems, including Griffiths phase in spin glasses, spin glasses on the Bethe lattice, sliding charge-density waves; liquid crystals; Blue Phases as networks of defect lines and in curved space; boojums in chiral smectic films; quantum instanton methods for atomic tunneling; early Berry's phase work in high-temperature superconductors; atomic tunneling from an STM/AFM tip; theory of vortex core states in superconductors; dynamical systems, including transition to chaos from quasiperiodic motion using renormalization group; noise in crumpling paper

Current Research

We've recently been interested in common, universal features we find in nonlinear optimization problems with many parameters; these sloppy models came up in our biological work on signal transduction. In materials physics, we have a new theory of dislocation dynamics in metals - explaining the formation both of grain boundies and dislocation patterns as singularities formed by the dynamics, similar to the shock wave singularities in sonic booms and traffic jams.

Graduate student associated with this group: Bryan Daniels, Mark Transtrum, Yong Chen, Ben Machta, Woo Song Choi and Yan-Jiun Chen

Spotlight

Yan-Jiun Chen is a graduate student working with Professor Jim Sethna studying non-equilibrium statistical physics, in particular, the scaling properties of crackling noise in magnets.  As a magnet is magnetized, magnetic spins flip in avalanches of all different sizes, this is called the Barkhausen effect (or crackling noise). The properties of these avalanches exhibit self-similarity, and can be studied using powerful theoretical tools in the form of the renormalization group (RG).  This means that studying these avalanches can tell us ...
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