Is there slow particle transport in the MBL phase?

Understand

We analyze the saturation value of the bipartite entanglement and number entropy starting from a random product state deep in the MBL phase.

• By studying the probability distributions of these entropies we find that the growth of the saturation value of the entanglement entropy stems from a significant reshuffling of the weight in the probability distributions from the bulk to the exponential tails.
• In contrast, the probability distributions of the saturation value of the number entropy are converged with system size, and exhibit a sharp cut-off for values of the number entropy which correspond to one particle fluctuating across the boundary between the two halves of the system.
• Our results therefore rule out slow particle transport deep in the MBL phase and confirm that the slow entanglement entropy production stems uniquely from configurational entanglement.