Astrophysical and cosmological observations currently provide the only
robust, empirical measurements of dark matter. Future observations with Large
Synoptic Survey Telescope (LSST) will provide necessary guidance for the
experimental dark matter program. This white paper represents a community
effort to summarize the science case for studying the fundamental physics of
dark matter with LSST. We discuss how LSST will inform our understanding of the
fundamental properties of dark matter, such as particle mass, self-interaction
strength, non-gravitational couplings to the Standard Model, and compact object
abundances. Additionally, we discuss the ways that LSST will complement other
experiments to strengthen our understanding of the fundamental characteristics
of dark matter. More information on the LSST dark matter effort can be found at
https://lsstdarkmatter.github.io/