[jerf]

To really, really get it? The standard electromagnetism semester and a QM semester, both "for majors" (not the simplified general version), and something else for the "inviscid compressible fluid" (fluid dynamics, I assume, this might require some stuff that won't come up until semester 2, not sure), and a factor difficult to express in terms of semesters that you are not merely aping the mathematical results you are being taught by rote, but actually understand how to manipulate the math and follow deeply when you see other people do it. (Which I mean quite straight, not sarcastically.)

I'm pretty sure this would all be accessible to an undergrad physics major who passes my math criterion above. It would probably be beyond them to do the work, but they should be able to follow it.

[rayiner]

An aerospace major who took a QM elective, or a physics major who took a couple of aerodynamics electives, would probably cover the necessary material by the end of year 2 of an undergraduate program. If you've got a solid, intuitive grasp of calculus and differential equations, you could probably learn enough from lecture notes to understand this in a few weeks. This is the most accessible physics paper that you'll ever see make the news.