In the past decade there has been a flurry of activity at the intersection of spectral theory and symplectic geometry. In this paper we review recent results on semiclassical spectral theory for commuting Berezin-Toeplitz and $\hbar$-pseudodifferential operators. The paper emphasizes the interplay between spectral theory of operators (quantum theory) and symplectic geometry of Hamiltonians (classical theory), with an eye towards recent developments on the geometry of finite dimensional integrable systems.
"Symplectic spectral geometry of semiclassical operators." Bull. Belg. Math. Soc. Simon Stevin 20 (3) 405 - 415, august 2013. https://doi.org/10.36045/bbms/1378314505