Strongly anomalous non-thermal fixed point in a quenched two-dimensional Bose gas

Understand

Universal scaling behavior in the relaxation dynamics of an isolated two-dimensional Bose gas is studied by means of semi-classical stochastic simulations of the Gross-Pitaevskii model.

• The system is quenched far out of equilibrium by imprinting vortex defects into an otherwise phase-coherent condensate.
• A strongly anomalous non-thermal fixed point is identified, associated with a slowed decay of the defects in the case that the dissipative coupling to the thermal background noise is suppressed.
• At this fixed point, a large anomalous exponent $\eta \simeq -3$ and, related to this, a large dynamical exponent $z \simeq 5$ are identified.