BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:O.V. Lychkovskiy DTSTART:20240907T134000Z DTEND:20240907T151000Z DTSTAMP:20260423T005705Z UID:QOART/33 DESCRIPTION:Title: M any-body correlation functions by the recursion method: symbolic nested co mmutators\, universal operator growth hypothesis and pseudomode expansion< /a>\nby O.V. Lychkovskiy as part of Quantum Optics and Related Topics\n\n\ nAbstract\nRecursion method is a technique to solve coupled Heisenberg equ ations in a tridiagonal operator basis constructed via Lanczos algorithm. We report an implementation of the recursion method that addresses quantu m many-body dynamics in the nonperturbative regime. The implementation has three key ingredients: a computer-algebraic routine for symbolic calculat ion of nested commutators\, a procedure to extrapolate the sequence of Lan czos coefficients according to the universal operator growth hypothesis an d the pseudomode expansion addressing the large time asymptotics. We apply the method to calculate infinite-temperature correlation functions for sp in-1/2 systems on one- and two-dimensional lattices. The method allows one to accurately calculate transport coefficients. As an illustration\, we c ompute the diffusion constant for the transverse-field Ising model on a sq uare lattice. The talk is based on arXiv 2401.17211\, 2407.12495. \n\nThe research is supported by the Russian Science Foundation under the grant No . 24-22-00331.\n LOCATION:https://researchseminars.org/talk/QOART/33/ END:VEVENT END:VCALENDAR