  It is increasingly important to understand the spatial dynamics of epidemics.
While there are numerous mathematical models of epidemics, there is a scarcity
of physical systems with sufficiently well-controlled parameters to allow
quantitative model testing. It is also challenging to replicate the macro
non-equilibrium effects of complex models in microscopic systems. In this work,
we demonstrate experimentally a physics analog of epidemic spreading using
optically driven non-equilibrium phase transitions in strongly interacting
Rydberg atoms. Using multiple laser beams we can impose any desired spatial
structure. We observe spatially localized phase transitions and their interplay
in different parts of the sample. These phase transitions simulate the outbreak
of an infectious disease in multiple locations, as well as the dynamics towards
herd immunity and endemic state in different regimes. The reported results
indicate that Rydberg systems are versatile enough to model complex
spatial-temporal dynamics.
