>>12586206String theory originally came out of work on quantum chromodynamics, and many of the results from string theorists are still useful there. Holography is a really interesting result that may have some pretty profound consequences. People are using holographic techniques to map strongly interacting theories to simpler problems, which could be a big deal for understanding the behavior of weirdly behaving metals.
>>12586288Yes, pretty much all advances of the 20th and 21st centuries in chemistry, materials science, electronics, optical communication, quantum computing and cryptography, particle and radiation therapy, and radiology are based on a quantum understanding of the world.
Relativity is important to many of these applications through its implications for high energy systems but also sees use in non-quantum systems that require precise timekeeping, especially aerospace applications like GPS.
