The Dynamics of Quantum Fluids

TL;DR

This paper reviews recent experimental and theoretical advances in understanding the complex dynamics of quantum fluids helium-4 and helium-3, highlighting their elementary excitations and rich behaviors.

Contribution

It provides a comprehensive overview of the latest progress in describing the dynamics of quantum fluids, integrating experimental data with theoretical insights.

Findings

Identification of phonons and rotons as elementary excitations

High-precision measurements reveal complex fluid behaviors

Theoretical models now capture the rich dynamics of helium fluids

Abstract

We review experimental and theoretical progress in the physical description of the dynamics of the quantum fluids \he4 and \he3. Historically, the elementary excitations in these systems have been identified as phonons and rotons and, in \he3, collective zero sound and spin-fluctuations. Both recent high-precision measurements and theoretical methods have shown that the dynamics of these systems is actually very rich as will be discussed in detail in the body of this contribution.