arXiv:2308.09316 · Physical review. B./Physical review. B
Nonadiabatic effect in topological and interacting charge pumping
Fan Yang, Xingyu Li, Hui Zhai
Abstract
Topological charge pumping occurs in the adiabatic limit, and the nonadiabatic effect due to finite driving velocity reduces the pumping efficiency and leads to deviation from quantized charge pumping. In this paper, we discuss the relation between this deviation from quantized charge pumping and the entanglement generation after a pumping circle. In the simplest setting, we show that the purity $\mathcal{P}$ of the half-system reduced density matrix is equal to $\mathcal{R}$, defined as ${(1\ensuremath{-}\ensuremath{\kappa})}^{2}+{\ensuremath{\kappa}}^{2}$, where $\ensuremath{\kappa}$ denotes the pumping efficiency. In generic situations, we argue that $\mathcal{P}<\mathcal{R}$ and the pumping efficiency can provide an upper bound for purity and, therefore, a lower bound for generated entanglement. To support this conjecture, we propose a solvable pumping scheme in the Rice-Mele-Hubbard model, which can be represented as a brick-wall-type quantum circuit model. With this pumping scheme, numerical calculation of charge pumping only needs to include at most six sites, and therefore the interaction and the finite-temperature effects can be both included reliably in the exact diagonalization calculation. The numerical results using the solvable pumping circle identify two regimes where the pumping efficiency is sensitive to driving velocity and support the conjecture $\mathcal{P}<\mathcal{R}$ when both interaction and finite-temperature effects are present.