In this talk I will discuss a new model for producing ultra-light, 
dark photon dark matter and a new observational strategy for probing 
ultra-light, axion-like particles.  In regard to dark photons, it is 
notoriously difficult to explain how this dark matter candidate was 
produced in the early universe, and I will discuss how dark photons 
can arise from a network of cosmic strings.  In regard to axions, it 
is well-known that the anomalous cooling of compact stars can provide 
an indirect probe of these weakly-coupled particles, and I will discuss 
how X-ray observations of magnetic white dwarf stars provide a new test 
of these theories.
