The history of cosmic expansion as revealed by the Dark Energy Spectroscopic Instrument

The Dark Energy Spectroscopic Instrument (DESI) survey is an ongoing program to study the expansion history of the Universe and the growth of large-scale structure.  After an introduction to large-scale structure, baryon acoustic oscillations (BAO) and the DESI survey, I will present the DESI Year 3 BAO measurements -- the most precise such measurements ever -- that constrain the expansion history of the Universe.  I will discuss the implications of these measurements for cosmology and fundamental physics, including dark energy and neutrino masses, and what to expect from DESI in the coming years.