Dimension Crossing Turbulent Cascade in an Excited Lattice Bose Gas

TL;DR

This paper reports the experimental observation of a dimension-crossing turbulent energy cascade in a 2D optical lattice Bose-Einstein condensate, revealing universal behaviors in energy redistribution across different dimensions.

Contribution

It introduces the first observation of a turbulent cascade crossing dimensions in a quantum many-body system, linking 2D lattice dynamics to 1D turbulence.

Findings

Energy cascades from 2D lattice to 1D dimension.

Universal behaviors in energy redistribution across dimensions.

Potential implications for cosmological models.

Abstract

Turbulence is an intriguing non-equilibrium state, which originates from fluid mechanics and has far-reaching consequences in the description of climate physics, the characterization of quantum hydrodynamics, and the understanding of cosmic evolution. The concept of turbulent cascade describing the energy redistribution across different length scales offers one profound route to reconcile fundamental conservative forces with observational energy non-conservation of accelerating expansion of the universe bypassing the cosmological constant. Here, we observe a dimension crossing turbulent energy cascade in an atomic Bose-Einstein condensate confined in a two-dimensional (2d) optical lattice forming a 2d array of tubes, which exhibits universal behaviors in the dynamical energy-redistribution across different dimensions. By exciting atoms into the optical-lattice high bands, the excessive energy of this quantum many-body system is found to cascade from the transverse two-dimensional lattice directions to the continuous dimension, giving rise to a one-dimensional turbulent energy cascade, which is in general challenging to reach due to integrability. We expect this observed novel phenomenon of dimension-crossing energy cascade may inspire microscopic theories for modeling positive cosmological constant of our inflationary universe.