Abstract :

A recreational puzzle posed 175 years ago of 15 schoolgirls to walk three abreast to school for seven days of the week so that no girl sees a friend repeated in her row has links to many areas of mathematics: combinatorics, finite projective geometries, design and coding theory, etc. There is an interesting historic link of this problem to the 1938 Bombay Science Congress, resulting in a branch of mathematics born in India. The problem can also be linked to states and operators of two qubits in today's quantum information, those Lie algebras and groups also providing a systematic way to get the required arrangements of the girls. These patterns, that can be further linked to four-⁠colour vision and analogs in acoustics and sound, will be discussed. They may be useful for manipulating states and operators of a pair of qubits, with generalization also to multiple qubits.

Speaker's webpage: http://www.phys.lsu.edu/faculty/rau/