Signals of Axion Like Dark Matter in Time Dependent Polarization of
  Light
  We consider the search for axion-like particles (ALPs) by using time series
data of the polarization angle of the light. If the condensation of an ALP
plays the role of dark matter, the polarization plane of the light oscillates
as a function of time and we may be able to detect the signal of the ALP by
continuously observing the polarization. In particular, we discuss that the
analysis of the Fourier-transformed data of the time-dependent polarization
angle is powerful to find the signal of the ALP dark matter. We pay particular
attention to the light coming from astrophysical sources such as protoplanetary
disks, supernova remnants, the foreground emission of the cosmic microwave
background, and so on. We show that, for the ALP mass of $\sim
10^{-22}$--$10^{-19}\ {\rm eV}$, ALP searches in the Fourier space may reach
the parameter region which is unexplored by other searches yet.
