Non-equilibrium effective field theory and second sound

Abstract

We investigate the phenomenon of second sound in various states of matter from the perspective of non-equilibrium effective field theory (EFT). In particular, for each state of matter considered, we find that at least two (though sometimes multiple) qualitatively different EFTs exist at finite temperature such that there is always at least one EFT with a propagating second-sound wave and at least one with no such second-sound wave. To aid in the construction of these EFTs, we use the method of cosets developed for non-equilibrium systems. It turns out that the difference between the EFTs with and without second-sound modes can be understood as arising from different choices of a new kind of inverse Higgs constraint. Finally, we demonstrate that it is possible to bypass the need for new inverse Higgs constraints by formulating EFTs on a new kind of manifold that is like the usual fluid worldvolume, but with reduced gauge symmetries.

30 pages, reflects published version

References in corpus (7)

• Observation of second sound in graphite at temperatures above 100 K
• Low-Energy Quantum Effective Action for Relativistic Superfluids
• Towards an effective action for relativistic dissipative hydrodynamics
• (Re-)Inventing the Relativistic Wheel: Gravity, Cosets, and Spinning Objects
• The second law of thermodynamics from symmetry and unitarity
• Effective Field Theory for Quasicrystals and Phasons Dynamics
• Dynamical chemistry: non-equilibrium effective actions for reactive fluids

Cited by in corpus (5)

• Deformations, relaxation and broken symmetries in liquids, solids and glasses: a unified topological field theory
• A Holographic Superfluid Symphony
• U(1) quasi-hydrodynamics: Schwinger-Keldysh effective field theory and holography
• Holographic Schwinger-Keldysh field theory of SU(2) diffusion
• Effective field theory of fluctuating wall in open systems: from a kink in Josephson junction to general domain wall