The theory of atomic spectra (and, later, quantum mechanics) developed almost concurrently with some parts of the mathematical fields of linear algebra, the spectral theory of operators, operator algebras and, more broadly, functional analysis. Nonrelativistic quantum mechanics includes Schrödinger operators, and it has connections to atomic and molecular physics. Quantum information theory is another subspecialty.
the theory of atomic spectra (and later quantum mechanics) developed almost concurrently with some parts of the mathematical fields of linear algebra the spectral theory of operators operator algebras and more broadly functional analysis nonrelativistic quantum mechanics includes schrödinger operators and it has connections to atomic and molecular physics quantum information theory is another subspecialty