Random partitions and the quantum Benjamin-Ono hierarchy

Jack measures on partitions occur naturally in the study of continuum circular log-gases in generic background potentials V at arbitrary values \beta of Dyson’s inverse temperature. Our main result is a law of large numbers (LLN) and central limit theorem (CLT) for Jack measures in the macroscopic scaling limit, which corresponds to the large N limit in the log-gas. Precisely, the emergent limit shape and macroscopic fluctuations of profiles of these random Young diagrams are the push-forwards along V of the uniform measure on the circle (LLN) and of the restriction to the circle of a Gaussian free field on the upper half-plane (CLT), respectively. At \beta=2, this recovers Okounkov’s LLN for Schur measures (2003) and coincides with Breuer-Duits’ CLT for biorthogonal ensembles (2013). Our limit theorems follow from an all-order expansion (AOE) of joint cumulants of linear statistics, which has the same form as the all-order 1/N refined topological expansion for the log-gas on the line due to Chekhov-Eynard (2006) and Borot-Guionnet (2012). To prove our AOE, we rely on the Lax operator for the quantum Benjamin-Ono hierarchy with periodic profile V exhibited in collective field variables by Nazarov-Sklyanin (2013). The characterization of the limit laws as push-forwards follows from factorization formulas for resolvents of Toeplitz operators with symbol V due to Krein and Calderón-Spitzer-Widom (1958).Non UBCUnreviewedAuthor affiliation: MITGraduat