This section is a stealth introduction to functional analysis. He covers Hilbert spaces, self-adjoint operators, and the spectral theorem—essential for quantum mechanics. Many students use this chapter as a bridge from linear algebra to quantum theory.

Tushar Anand. https://doi.org/10.1007/978-3-030-39680-0. 790 pages. Academia.edu

You're looking for a paper on "Mathematical Physics" by V. Balakrishnan!

: Prioritizes physical applications (e.g., fluid dynamics, electromagnetism, and quantum mechanics) over rigorous theorem proofs.