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The 2012 Van Winter Memorial Lecture: Paul Steinhardt and Quasicrystals

Each year, the Department of Mathematics and the Department of Physics and Astronomy jointly organize the Van Winter Memorial Lecture, which brings in distinguished speakers to give lectures on matters of common interest to mathematicians and physicists.

This year's speaker is Paul Steinhardt, professor of physics and astrophysics at Princeton University, and director of the Princeton Center for Theoretical Sciences. In this podcast, we spoke to Sumit Das, who will be hosting the lecture, about some of professor Steinhardt's research.

Professor Steinhardt's lecture will be titled, "Once Upon a Time in Kamchatka: the Extraordinary Search for Natural Quasicrystals." The presentation will be on Friday, March 23, from 3:15 pm to 4:15 pm, in room 139 of the Chemistry-Physics building.

In short, a quasicrystal is a type of structure that shows rotational symmetry, but is not periodic -- it doesn't have a pattern that repeats over a distance. Quasicrystals can be composed of sets of a few shapes that are arranged to fill up a space, and although they may have radial patterns, these do not repeat around the crystal in any noticeable order. Usually, it has been thought that crystals can only have two-, four-, or six-sided radial patterns, but quasicrystals can have five-sided rotational symmetry as well, such as in these structures:

A Penrose tiling of thick and thin rhombi.An atomic model of fivefold icosahedral-Al-Pd-Mn quasicrystal surface.A Penrose tiling using thick and thin rhombi.

 

 

 

 

 

This podcast was produced by Stephen Gordinier.

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