## Paul Steinhardt's lecture from March 5, 2020

Oliver Knill, Harvard University, March 19, 2020

It is a bit sad to look back at this great event organized by the Harvard bookstore
and the physics department. The last few semesters have been fantastic in this
respect (I was told, Melissa Franklin was the architect of this lecture series).
It is now only 2 weeks ago. How much has changed!
The story of Steinhardt is fascinating. I had witnessed the quasi-crystal revolution
as an undergraduate and was influenced much by it (similarly as chaos theory did).
Some of my own work was influenced by it (example:
almost periodic sphere
packing, Almost periodic fluids,
Almost periodic cellular automata,
Almost periodic Dirichlet series,
or Palindromic Schroedinger operators, or
Almost periodic Birkhoff sums).
The interest had also been sparked by questions in ergodic theory, statistical mechanics,
KAM theory and functional analysis
(Moser mentioned almost periodic functions even in his functional analysis classes).
As a graduate student, I have met Bert Hof, who just finished his marvelous
thesis on quasicrystals, aperiodicity and lattice systems and we would have some
wonderful collaborations together later on as post-docs. Also at UTexas Austin, there was a strong
group interested in quasi-crystals (Radin, Sadun) and KAM (Koch, DeLaLlave. Click on a picture to see it larger.

* Oliver Knill, Posted March 19, 2020 *