FIG. 4.

Relaxation in a quadratic field. a, We reconfigure the site-resolved field from a linear gradient to a quadratic, characterized by the maximum slope γ. For clarity, we show N = 7. b, Dynamics are split into a thermalizing region near the center of the system and localized regions near the edges, with the approximate boundaries indicated by the dashed lines. As the maximum gradient is increased, the fraction of the system in the thermalizing regime shrinks. c, Ion-resolved traces of the dynamics for max g/J₀ = 1.8, showing separation of the spins into localizing regions (bright hues with round points) and thermalizing regions (faded hues with square points). Colors reflect the local field strength at each ion.