Thermodynamics of perfect fluids from scalar field theory

Understand

The low-energy dynamics of relativistic continuous media is given by a shift-symmetric effective theory of four scalar fields.

• These scalars describe the embedding in spacetime of the medium and play the role of St\"uckelberg fields for spontaneously broken spatial and time translations.
• Perfect fluids are selected imposing a stronger symmetry group or reducing the field content to a single scalar.
• We explore the relation between the field theory description of perfect fluids to thermodynamics.