Well the two uses I'm most familiar with are AC circuit analysis and quantum mechanics. They can both be reformulated without complex numbers of course, since n

Well the two uses I'm most familiar with are AC circuit analysis and quantum mechanics. They can both be reformulated without complex numbers of course, since nothing is special about i. Yet the complex versions are a lot easier to work with, because even in manifestly real formulations, the complex structure is still there, but in disguise: - http://www.scottaaronson.com/democritus/lec9.html http://www.scottaaronson.com/democritus/lec9.html - http://physics.stackexchange.com/questions/32422/qm-without-complex-numbers http://physics.stackexchange.com/questions/32422/qm-without-...