My favorite formulation of Maxwell's equations is ◻²A = J where A is the 4-potential, J is the 4-current, and ◻² is the 4-Laplacian or d'Alembertian (https://

My favorite formulation of Maxwell's equations is ◻²A = J where A is the 4-potential, J is the 4-current, and ◻² is the 4-Laplacian or d'Alembertian (https://en.wikipedia.org/wiki/Classical_electromagnetism_and_special_relativity#4-potential https://en.wikipedia.org/wiki/Classical_electromagnetism_and...). The reason this is so elegant is because it is both manifestly covariant and manifestly a wave equation. See https://physics.stackexchange.com/questions/201847/why-is-the-wave-equation-so-pervasive https://physics.stackexchange.com/questions/201847/why-is-th.... Furthermore, conservation of 4-current is given by ◻·J = 0 where ◻· is the 4-divergence. Again, the equation is manifestly covariant and very elegant. There are reasons to believe that the electromagnetic potential is in a sense more fundamental than the electromagnetic field: https://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect https://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect