What is a good spike that combines physics and computer science?
have a look at RP some good ideas there
what’s rp?
You can go with quantum computing. Quantum Cryptography, if you really want to get into it. It’s such an interesting and up-and-coming field but there aren’t many high school students learning about it. If you’re serious, try applying for the 2021 QCSYS program in Canada.
A pretty standard field would be engineering, but classical physics tend to get a bit meh. Hope this helps!