81Q05 Closed and approximate solutions to the Schrödinger, Dirac, Klein-Gordon and other quantum-mechanical equations
81Q10 Selfadjoint operator theory in quantum theory, including spectral analysis
81Q15 Perturbation theories for operators and differential equations
81Q20 Semiclassical techniques including WKB and Maslov methods
81Q30 Feynman integrals and graphs; applications of algebraic topology and algebraic geometry [See also 14D05, 32S40]
81Q40 Bethe-Salpeter and other integral equations
81Q50 Quantum chaos [See also 37Dxx]
81Q60 Supersymmetric quantum mechanics
81Q70 Differential-geometric methods, including holonomy, Berry and Hannay phases, etc.
81Q99 None of the above, but in this section