Contributor info: Dr Natalia Pinzani-Fokeeva

Natalia Pinzani-Fokeeva, Amos Yarom

SciPost Phys. 12, 136 (2022) · published 21 April 2022 | Toggle abstract · pdf

We construct an approximately conserved current for $2+1$ dimensional, Aristotelian (non boost invariant), fluid flow. When Aristotelian symmetry is enhanced to Galilean symmetry, this current matches the enstrophy current responsible for the inverse cascade in incompressible fluids. Other enhancements of Aristotelian symmetry discussed in this work include Lorentzian, Carrollian and Lifshitz scale symmetry.

Raja Marjieh, Natalia Pinzani-Fokeeva, Amos Yarom

SciPost Phys. 12, 085 (2022) · published 9 March 2022 | Toggle abstract · pdf

We study symmetry principles associated with the approximately conserved enstrophy current, responsible for the inverse energy cascade in non relativistic 2+1 dimensional turbulence. We do so by identifying the accidental symmetry associated with enstrophy current conservation in a recently realized effective action principle for hydrodynamics. Our analysis deals with both relativistic and non relativistic effective actions and their associated symmetries.

Kristan Jensen, Raja Marjieh, Natalia Pinzani-Fokeeva, Amos Yarom

SciPost Phys. 5, 053 (2018) · published 27 November 2018 | Toggle abstract · pdf

We classify all possible allowed constitutive relations of relativistic fluids in a statistical mechanical limit using the Schwinger-Keldysh effective action for hydrodynamics. We find that microscopic unitarity enforces genuinely new constraints on the allowed transport coefficients that are invisible in the classical hydrodynamic description; they are not implied by the second law or the Onsager relations. We term these conditions Schwinger-Keldysh positivity and provide explicit examples of the various allowed terms.