A recent analysis highlights how small-scale cosmic structure has become a fundamental tool for investigating the fundamental nature of dark matter (DM). Alternative models to the standard cold dark matter (CDM) paradigm, such as warm, fuzzy, or self-interacting dark matter, predict distinct effects on matter distribution at small scales. These models modify the abundance and internal structure of dark matter halos through phenomena like free-streaming, wave interference, or interactions with the Standard Model, leaving observable imprints in the universe.

Cosmological and astrophysical probes of nonlinear structure are particularly sensitive to these effects. These include dwarf galaxies, strong gravitational lensing, the Lyman-α forest, stellar streams, and high-redshift galaxies. The study focuses on the constraints these observations impose on dark matter, paying special attention to scales smaller than approximately 1 Mpc, which represent the current frontier of measurements. It details how these constraints have been translated into limits for microphysical dark matter models, as well as key modeling uncertainties and observational systematics.

The work emphasizes the growing importance of combining different probes and simulation-based inference to advance this field. Furthermore, it anticipates future observational facilities that will allow for further refinement of dark matter physics tests through small-scale structure. These advances are crucial for distinguishing between proposed models and, ultimately, for understanding the true nature of dark matter, one of the greatest mysteries in modern physics.