#### Vol. 296, No. 2, 2018

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Length spectra of sub-Riemannian metrics on compact Lie groups

### András Domokos, Matthew Krauel, Vincent Pigno, Corey Shanbrom and Michael VanValkenburgh

Vol. 296 (2018), No. 2, 321–340
##### Abstract

Length spectra for Riemannian metrics have been well studied, while sub-Riemannian length spectra remain largely unexplored. Here we give the length spectrum for a canonical sub-Riemannian structure attached to any compact Lie group by restricting its Killing form to the sum of the root spaces. Surprisingly, the shortest loops are the same in both the Riemannian and sub-Riemannian cases. We provide specific calculations for $SU\left(2\right)$ and $SU\left(3\right)$.

##### Keywords
sub-Riemannian geometry, geodesics, root systems, compact Lie groups
##### Mathematical Subject Classification 2010
Primary: 53C17, 53C22
Secondary: 22E30, 51N30