A Nonequilibrium Equation of State for a Turbulent 2D Bose Gas

TL;DR

This paper develops a nonequilibrium equation of state for a turbulent 2D Bose gas, linking energy flux and cascade amplitude, and demonstrating universal scaling behavior in a far-from-equilibrium quantum system.

Contribution

It introduces a novel nonequilibrium equation of state for a turbulent 2D Bose gas, connecting cascade dynamics with thermodynamic-like descriptions.

Findings

Established a power-law momentum distribution in a driven 2D Bose gas.

Derived a universal power-law form of the equation of state across different parameters.

Linked cascade amplitude to energy flux in a nonequilibrium quantum system.

Abstract

Nonequilibrium equations of state can provide an effective thermodynamic-like description of far-from-equilibrium systems. We experimentally construct such an equation for a direct energy cascade in a turbulent two-dimensional Bose gas. Our homogeneous gas is continuously driven on a large length scale and, with matching dissipation on a small length scale, exhibits a nonthermal but stationary power-law momentum distribution. Our equation of state links the cascade amplitude with the underlying scale-invariant energy flux, and can, for different drive strengths, gas densities, and interaction strengths, be recast into a universal power-law form using scalings consistent with the Gross-Pitaevskii model.