“…Structure-preserving particle-in-cell (PIC) algorithms preserve many of the geometric and topological mathematical structures of a point-particle kinetic plasma model, including its symplectic structure, symmetries, conservation laws and cohomology (Villasenor & Buneman 1992;Esirkepov 2001;Squire, Qin & Tang 2012;Evstatiev & Shadwick 2013;Xiao et al 2013;Crouseilles, Einkemmer & Faou 2015;He et al 2015;Moon, Teixeira & Omelchenko 2015;Qin et al 2015Qin et al , 2016Xiao et al 2015;He et al 2016;Burby 2017;Kraus & Hirvijoki 2017;Morrison 2017;Xiao, Qin & Liu 2018;Xiao & Qin 2019;Glasser & Qin 2020;Hirvijoki, Kormann & Zonta 2020;Holderied, Possanner & Wang 2021;O'Connor et al 2021;Perse, Kormann & Sonnendrücker 2021;Pinto, Kormann & Sonnendrücker 2022;Wang et al 2021;Xiao & Qin 2021). One such structure, gauge symmetry, was first preserved in a PIC algorithm in the Lagrangian formalism via a variational method (Squire et al 2012).…”