  The spin-boson model is a prototypical model for open quantum dynamics. Here
we simulate the spin-boson model using a chain of trapped ions where a spin is
coupled to a structured reservoir of bosonic modes. We engineer the spectral
density of the reservoir by adjusting the ion number, the target ion location,
the laser detuning to the phonon sidebands, and the number of frequency
components in the laser, and we observe their effects on the collapse and
revival of the initially encoded information. Our work demonstrates the ion
trap as a powerful platform for simulating open quantum dynamics with
complicated reservoir structures.
