I used to speak Arabic very well. I helped translate for the Palestinian post-doc I met at Harvard his lectures from Arabic to English. My book isn’t based on his research, but I learned about the field through him. For my book, I researched what discoveries were expected over the next twenty years and that’s where I got the idea for what my protagonist discovers.
I actually know nothing about math and science so I had some students do the equations. There are actually 3 problems that are solved incorrectly. The Italian editor discovered them when he was translating the book.