Do quantum fluctuations change nonthermal fixed-point exponents
In plain words
Most theory of these scaling stages treats the atoms' matter wave as a classical field with random noise, which works when many atoms share each state. Whether genuinely quantum effects change the universal behaviour, for example at strong interactions, is untested.
Precise statement
Classical-statistical (truncated Wigner) simulations reproduce nonthermal fixed points when occupations $f(k) >> 1$ in the scaling window. In strongly interacting or low-occupation regimes (e.g. the 1D Lieb-Liniger gas with dimensionless coupling $\gamma >\sim 1$, or the Bose-Hubbard model at $U/J >\sim 10$), determine whether $\alpha$ and $\beta$ differ from the classical-field values for the same initial conditions. Answer yes or no, with the exponents.
What would settle it
Fully quantum simulation (tensor networks in 1D, or quantum-simulator data) of the scaling window compared with truncated-Wigner exponents at identical parameters.