Kardar-Parisi-Zhang scaling in the Hubbard model
Cătălin Paşcu Moca, Miklós Antal Werner, Angelo Valli, Tomaž Prosen, Gergely Zaránd
Abstract
We explore the Kardar-Parisi-Zhang (KPZ) scaling in the one-dimensional Hubbard model, which exhibits global $S{U}_{c}(2)\ensuremath{\bigotimes}S{U}_{s}(2)$ symmetry at half filling, for the pseudocharge and the total spin. We analyze dynamical scaling properties of high-temperature charge and spin correlations and transport. At half filling, we observe a clear KPZ scaling in both charge and spin sectors. Away from half filling, the $S{U}_{c}(2)$ charge symmetry is reduced to ${U}_{c}(1)$, while the $S{U}_{s}(2)$ symmetry for the total spin is retained. Consequently, transport in the charge sector becomes ballistic, while KPZ scaling is preserved in the spin sector. These findings confirm the link between non-Abelian symmetries and KPZ scaling in the presence of integrability. We study two settings of the model: one involving a quench from a bipartitioned state asymptotically close to the $T=\ensuremath{\infty}$ equilibrium state of the system, and another where the system is coupled to two Markovian reservoirs at the two edges of the chain.