Recently, a new technique called kinematic Sunyaev-Zel’dovich (kSZ) tomography has emerged as a potentially powerful probe of cosmology. With kSZ tomography, correlations between cosmic microwave background and galaxy survey data allow us to reconstruct the peculiar velocity field of large-scale structure. 
In this talk, I will discuss how we can leverage the information in the velocity field to probe fundamental physics, focusing on two applications. First, I will show how we can use kSZ tomography to search for new physics from the primordial Universe, for example in the form of light particles during inflation. In the second application, we will pivot to the late Universe and explore the possibility of using the velocity field as a probe of the neutrino masses. Finally, I will speculate about some avenues for future progress with kSZ tomography and cosmological probes of fundamental physics.