BEGIN:VCALENDAR VERSION:2.0 PRODID:-//jEvents 2.0 for Joomla//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VTIMEZONE TZID:America/New_York BEGIN:STANDARD DTSTART:20231105T010000 RDATE:20240310T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20241103T010000 RDATE:20250309T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20251102T010000 RDATE:20260308T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20261101T010000 RDATE:20270314T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20271107T010000 RDATE:20280312T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20281105T010000 RDATE:20290311T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:DAYLIGHT DTSTART:20230327T104500 RDATE:20231105T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20240310T030000 RDATE:20241103T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20250309T030000 RDATE:20251102T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20260308T030000 RDATE:20261101T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20270314T030000 RDATE:20271107T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20280312T030000 RDATE:20281105T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT END:VTIMEZONE BEGIN:VEVENT UID:a88e62c1b1dce697516d0e8aa2af6187 CATEGORIES:Mathematical Physics Seminar CREATED:20240314T230127 SUMMARY:Webinar: Gregory Eyink - Fluid Turbulence and Statistical Physics Collide   DESCRIPTION:MATHEMATICAL PHYSICS WEBINAR\n RUTGERS UNIVERSITY\n________________________ __________________\n  \nGregory Eyink – Johns Hopkins University\nWednesday , March 27th, 10:45AM EDT (Zoom meeting starts at 10:30 EDT) \n \nFluid Tur bulence and Statistical Physics Collide  \nWe present an overview of recent  developments in fluid turbulence and new perspectives that they suggest in statistical physics. We begin with studies of effects of thermal fluctuati ons in very low Reynolds-number turbulence, which challenge the view of "ma croscopic fluctuation theory” that hydrodynamic behavior arises as a law of large numbers in a “scaling limit.” Instead, these studies support an alte rnative idea that fluctuating hydrodynamics originates from molecular dynam ics as a low-wavenumber “effective field theory”. This point of view has im plications also for laminar flows. For example, an asymptotic high-Schmidt theory of liquid diffusion by Donev, Fai and vanden-Eijnden based on nonlin ear fluctuating hydrodynamics predicts that non-equilibrium concentration f luctuations in a liquid at rest subject to a concentration gradient arise b y a turbulent cascade process. This cascade generates non-Gaussian fluctuat ions with order unity skewness and flatness, inconsistent with a central li mit theorem. Experimental measurement of these higher-order correlations ma y therefore be able to distinguish between “effective field theory” and “ma croscopic fluctuation theory”. Furthermore, we present evidence that even a t very high Reynolds numbers effects of tiny thermal fluctuations can rando mize the largest eddies of a turbulent flow, contradicting a deterministic “law of large numbers”. This effect arises from “spontaneous stochasticity” , a weak-noise critical behavior associated to an infinite number of fluid histories with zero  Onsager-Machlup action (deterministic Euler solutions) , analogous to infinitely many ground states in mean-field spin glasses. Ex act renormalization group analysis of simple 1D models of spontaneous stoch asticity derives a novel “singular large deviations” mediated by non-unique  zero-action histories, distinct from the standard large-deviations due to  weak-noise instantons which is predicted by macroscopic fluctuation theory.  \n \n This talk is based on joint work with Nigel Goldenfeld, Dima Bandak, Alexei Mailybaev, John Bell, Alej Garcia, Andy Nonaka, and Amir Jafari. \n X-ALT-DESC;FMTTYPE=text/html:

MATHEMATICAL PHYS ICS WEBINAR
RUTGERS UNIVERSITY

__________________________________________

  

Gregory Eyink – Joh ns Hopkins University

Wednesday, March 27th, 10:45AM EDT (Zoom me eting starts at 10:30 EDT) 

 

Fluid Turbulence and Statistical&n bsp;Physics Collide  

We present an overview of recent& nbsp;developments in fluid turbulence and new perspectives that they s uggest in statistical physics. We begin with studies of effe cts of thermal fluctuations in very low Reynolds-number turbulence, wh ich challenge the view of "macroscopic fluctuation theory” that h ydrodynamic behavior arises as a law of large numbers in a “ scaling limit.” Instead, these studies support an alternative ide a that fluctuating hydrodynamics originates from molecular dynamics as  a low-wavenumber “effective field theory”. This point of view has imp lications also for laminar flows. For example, an asymptotic high -Schmidt theory of liquid diffusion by Donev, Fai and vanden-Eijn den based on nonlinear fluctuating hydrodynamics predicts that non-equ ilibrium concentration fluctuations in a liquid at rest subject to a c oncentration gradient arise by a turbulent cascade process. This cascade generates non-Gaussian fluctuations with order unity skew ness and flatness, inconsistent with a central limit theorem. Exp erimental measurement of these higher-order correlations may therefore be&n bsp;able to distinguish between “effective field theory” and “macroscopic f luctuation theory”. Furthermore, we present evidence that even at very high Reynolds numbers effects of tiny thermal fluctuations can randomize the largest eddies of a turbulent flow, contradicting a  deterministic “law of large numbers”. This effect arises from “spontaneous& nbsp;stochasticity”, a weak-noise critical behavior associated to an i nfinite number of fluid histories with zero  Onsager-Machlup  ;action (deterministic Euler solutions), analogous to infinitely many groun d states in mean-field spin glasses. Exact renormalization group analy sis of simple 1D models of spontaneous stochasticity derives a no vel “singular large deviations” mediated by non-unique zero-actio n histories, distinct from the standard large-deviations due to&n bsp;weak-noise instantons which is predicted by macroscopic fluctuation&nbs p;theory. 

This talk is based on joint work with Nigel G oldenfeld, Dima Bandak, Alexei Mailybaev, John Bell, Alej Garcia, Andy Nonaka, and Amir Jafari. 

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