We derive exact and asymptotic results for random partitions from general results in the semi-classical analysis of coherent states. In geometric quantization of Hermitian affine spaces (M , J, g, ω), a coherent state Υ v (•| ) around a classical state v ∈ M is the reproducing kernel in the Fock space L 2 J-hol (M , dρ ,g ) of J-holomorphic functions on M square-integrable against the Segal-Bargmann Gaussian weight dρ ,g . Under certain regularity assumptions, in any canonical quantization defined by an ordering η, we prove that in the semi-classical limit → 01/2 with mean 0 and variance ||(∇O)| v || 2 g independent of η. These results do not assume integrability of the Hamiltonian flow generated by O but follow directly from the fact that at fixed > 0 the Segal-Bargmann weight on M is already Gaussian with covariance kernel g −1 given by the inverse metric.The classical periodic Benjamin-Ono equation for real 2π-periodic v of mean a ∈ R is Hamiltonian in the leaf (M (a), J, g −1/2 , ω −1/2 ) of the real L 2 -Sobolev space on the circle T at critical regularity s = −1/2 with J the spatial periodic Hilbert transform. We find a classical conserved density dF |v (c|ε) on c ∈ R for this system with dispersion coefficient ε, extending Nazarov-Sklyanin (2013). The authors also give an ordering η N S for an integrable canonical quantization, which we use to construct a quantum conserved density d F η N S (c| , ε)| Ψ . For quantum stationary states, we identify this conserved density with dF λ (c| ε 2 , ε 1 ) the Rayleigh measure of the profile of a partition λ of anisotropy (εAs Jack polynomials are the quantum stationary states and Stanley's Cauchy kernel (1989) is the reproducing kernel, the random values of the quantum periodic Benjamin-Ono hierarchy in a coherent state Υ v (•| ) are a "Jack measure" on partitions, a dispersive generalization of Okounkov's Schur measures (1999). By the above,we have concentration on a limit shape as → 0, the classical conserved density at v, and quantum fluctuations are an explicit Gaussian field. Our results follow from an enumerative asymptotic expansion in and ε of joint cumulants over new combinatorial objects we call "ribbon paths". As above, our results reflect the fact that at fixed > 0 the weight defining Fock space is already a fractional Brownian motion of variance and Hurst index (−s) − 1 2 dim T = + 1 2 − 1 2 = 0.