Abstract
Ultralight dark matter is a compelling dark matter candidate. Being wavelike, it has interesting phenomenological implications in the early and late universe. Recent simulations have shown that ultralight dark matter exhibits an order-one density fluctuation in galaxies. Such density fluctuations can be intuitively understood as quasiparticles. In this talk, we will discuss the statistical properties of density fluctuations (quasiparticles) and related phenomenological consequences. For instance, we will discuss how the wavelike nature of dark matter and density fluctuations could change the evolution of stellar objects as well as modify the pattern of gravitational waves from intermediate-mass ratio inspirals. We will also discuss the possibility to search for such density fluctuations with gravitational wave interferometers.