BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Ashish Shukla (Perimeter) DTSTART:20201119T150000Z DTEND:20201119T160000Z DTSTAMP:20260423T010012Z UID:HEPTUW/11 DESCRIPTION:Title: The Effective Field Theory for Hydrodynamics and its Analytic Properties\nby Ashish Shukla (Perimeter) as part of HEP seminars TU Wien (Vienna)\ n\n\nAbstract\nHydrodynamics provides an effective description for many-bo dy systems near thermal equilibrium. The success of the paradigm rests on the idea that the dynamics of such near-equilibrium systems can be capture d by a very small number of parameters\, such as the temperature and fluid velocity\, and their derivatives. For instance\, relativistic hydrodynami cs\, which is applicable to systems which respect the Lorentz symmetry\, h as been immensely successful in understanding the properties of the Quark- Gluon plasma that is produced in heavy-ion collisions at RHIC and CERN. In this talk\, I will start by reviewing the construction of hydrodynamics i n terms of a derivative expansion\, followed by a discussion of the equili brium generating functional and its properties. Interestingly\, though the standard formulation of hydrodynamics captures the dissipative aspects of the system quite well\, it does not take into account the effects of the underlying thermal fluctuations efficiently. One can remedy the situation to some extent by using the stochastic approach\, where one can introduce random Gaussian fluctuations and derive an effective action. However\, thi s approach has its limitations\, as the structure of the interaction terms in the effective action is quite restricted. Recently\, an effective fiel d theory (EFT) approach based on the Schwinger-Keldysh (SK) formalism has been proposed\, which systematically captures the effects of the underlyin g fluctuations\, making use of symmetries. In the second part of the talk\ , I will review the construction of the stochastic as well as the SK effec tive actions for a theory of charge diffusion. I will then discuss a simpl ifying limit of the SK diffusive EFT\, where the sound modes effectively d ecouple from the dynamics. I will discuss one-loop corrections to the reta rded and symmetric correlators in this model\, with special emphasis on th e role played by the KMS symmetry in ensuring the correct analytic structu re for the theory as required by the limit of thermal equilibrium\, provid ing a strong consistency check on the EFT framework.\n LOCATION:https://researchseminars.org/talk/HEPTUW/11/ END:VEVENT END:VCALENDAR