Reprint: Anomalous Diffusion and the Egg Crate Potential: A Numerical Study in Chaotic Hamiltonian Dynamics

M. Golladay, Roanoke College, Salem, VA


The motion of a classical particle in an "egg-crate" potential is modeled in an effort to understand chaotic Hamiltonian dynamics. While all energy levels are examined, our main interests are in energies that are associated with anomalous diffusion. However, periodic motion and classical Brownian motion are observed at various energy levels in the system. It is noted in particular that particles with energies between the saddle point of the potential and below the absolute maximum exhibit anomalous diffusion. The power spectra at these levels exhibit 1/f noise. Algebraic tails are present in the velocity autocorrelation functions of the energies with 1/f noise. Further exploration of these tails suggests that multiple types are present at different energies.

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Reprint: An Experimental Study of Stick-Slip Friction Using Sandpaper as a Simple Model of Earthquake Dynamics

Jason Foust, Mansfield University, Mansfield PA


An experimental study of stick-slip friction was conducted using sandpaper and paper towels. This study models stick-slip friction eqarthquakes. A block with sandpaper on its bottom was fixed to a strain guage by means of a spring. A paper towel was pulled beneath the block, stretching the spring, while the position of the block was monitored with a linear displacement gauge. Readings from the strain gauge and linear displacement gauge then were used to determine the energy released when the block slid backwards. Analysis of the data suggests that the interaction of the sandpaper with the paper towel depends on both the sandpaper grit size and the surface roughness of the paper towel.

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Meet the 2004 SPS Summer Interns and See Their Presentations

Learn more at the SPS website

2004 SPS National Research Awards


Outstanding Student Awards for Undergraduate Research

Angelo State University

Every year, SPS solicits from its student membership proposals for physics papers to be presented at the International Conference of Physics Students (ICPS). Winners receive a $500 honorarium and a $500 award for their SPS Chapter, as well as expenses for transportation, room, board, and registration. See the 2004 winners here.


Sigma Pi Sigma Undergraduate Research Awards

California State University San Marcos

The Sigma Pi Sigma Undergraduate Research Award program provides, on the basis of an anual competition among the active Chapters, calendar year grants to support local Chapter activities that are deemed imaginative and likely to contribute to the strengthening of the SPS program. See the 2004 winners here.