Supersymmetric sound in fluids

TL;DR

This paper explores the hydrodynamics of supersymmetric fluids, revealing a massless fermionic mode called the phonino, and analyzes its interactions and properties using two complementary theoretical approaches.

Contribution

It introduces a detailed theoretical framework for supersymmetric fluid hydrodynamics, including the phonino's behavior and non-dissipative diffusion terms, using generating functional and effective field theory methods.

Findings

Phonino is a massless fermionic mode in supersymmetric fluids.

Diffusion terms in the supercurrent are non-dissipative.

Entropy conservation is demonstrated in ideal supersymmetric fluids.

Abstract

We consider the hydrodynamics of supersymmetric fluids. Supersymmetry is broken spontaneously and the low energy spectrum includes a fermionic massless mode, the $\mathit{phonino}$. We use two complementary approaches to describe the system: First, we construct a generating functional from which we derive the equations of motion of the fluid and of the phonino propagating through the fluid. We write the form of the leading corrections in the derivative expansion, and show that the so called diffusion terms in the supercurrent are in fact not dissipative. Second, we use an effective field theory approach which utilizes a non-linear realization of supersymmetry to analyze the interactions between phoninos and phonons, and demonstrate the conservation of entropy in ideal fluids. We comment on possible phenomenological consequences for gravitino physics in the early universe.