Field theory spin and momentum in water waves

Area of Science:

• Physics
• Fluid Dynamics
• Quantum Field Theory

Background:

• Spin is a key property of quantum particles and fields in relativistic theory.
• The Belinfante-Rosenfeld construction describes spin density using momentum differences, often considered abstract.
• These concepts lack direct observation in classical systems.

Purpose of the Study:

• To demonstrate the Belinfante-Rosenfeld construction in a classical wave system.
• To experimentally observe fundamental spin and momentum properties in gravity waves.
• To explore the universality of relativistic field theory concepts.

Main Methods:

• Theoretical analysis of wave fields.
• Experimental setup using surface gravity waves.
• Measurement of canonical and kinetic momentum densities.
• Observation of subwavelength circular motion in water particles.

Main Results:

• The Belinfante-Rosenfeld construction was shown to naturally arise in water surface waves.
• Canonical momentum was linked to the generalized Stokes drift.
• Spin generation was observed through subwavelength circular water particle motion.
• Fundamental field theory properties were directly observed as mechanical properties.

Conclusions:

• Relativistic field theory concepts, including spin, are observable in classical mechanical systems.
• Water surface waves provide a novel platform for studying fundamental physics.
• The study bridges quantum phenomena with classical wave mechanics, enhancing understanding of spin and momentum.