BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Benjamin Doyon DTSTART:20211118T154500Z DTEND:20211118T173000Z DTSTAMP:20260423T022812Z UID:LIJC/57 DESCRIPTION:Title: Co rrelation functions of twist fields from hydrodynamics\nby Benjamin Do yon as part of London Integrability Journal Club\n\n\nAbstract\nThe Euler- scale power-law asymptotics of space-time correlation functions in many-bo dy systems\, quantum and classical\, can be obtained by projecting the obs ervables onto the hydrodynamic modes admitted by the model and state. This is the Boltzmann-Gibbs principle\; it works for integrable and non-integr able models alike. However\, certain observables\, such as some order para meters in thermal of generalised Gibbs ensembles\, do not couple to any hy drodynamic mode: the Boltzmann-Gibbs principle gives zero. I will explain how hydrodynamics can still give the leading exponential decay of order pa rameter correlation functions. With the examples of the quantum XX chain a nd the sine-Gordon model\, I will explain how large deviations of the spin and U(1) current fluctuations are related to such exponential decay. Exac t predictions are given by the ballistic fluctuation theory based on gener alised hydrodynamics. In the XX model\, this is in agreement with results obtained previously by a more involved Fredholm determinant analysis and o ther techniques\, and even gives a new formula for a parameter regime not hitherto studied. In the sine-Gordon model\, these are new results\, inacc essible by other techniques. Works in collaboration with Giuseppe Del Vecc hio Del Vecchio\, and Márton Kormos.\n LOCATION:https://researchseminars.org/talk/LIJC/57/ END:VEVENT END:VCALENDAR