  The concept of topological phases is a powerful framework to characterize
ground states of quantum many-body systems that goes beyond the paradigm of
symmetry breaking. While a few topological phases appear in condensed matter
systems, a current challenge is the implementation and study of such quantum
many-body ground states in artificial matter. Here, we report the experimental
realization of a symmetry protected topological phase of interacting bosons in
a one-dimensional lattice, and demonstrate a robust ground state degeneracy
attributed to protected edge states. The setup is based on atoms trapped in an
array of optical tweezers and excited into Rydberg levels, which gives rise to
hard-core bosons with an effective hopping by dipolar exchange interaction.
