Universal scaling at non-thermal fixed points of a two-component Bose gas

Understand

Quasi-stationary far-from-equilibrium critical states of a two-component Bose gas are studied in two spatial dimensions.

• After the system has undergone an initial dynamical instability it approaches a non-thermal fixed point.
• At this critical point the structure of the gas is characterised by ensembles of (quasi-)topological defects such as vortices, skyrmions and solitons which give rise to universal power-law behaviour of momentum correlation functions.
• The resulting power-law spectra can be interpreted in terms of strong-wave-turbulence cascades driven by particle transport into long-wave-length excitations.