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SUMMARY:Constraining Axion Fields in the Late Universe - Anastasios Avgous
 tidis (University of Nottingham)
DTSTART:20140512T120000Z
DTEND:20140512T130000Z
UID:TALK51890@talks.cam.ac.uk
CONTACT:Camille Bonvin
DESCRIPTION:Scalar fields are ubiquitous in fundamental theories of the ea
 rly universe. Axions\, for example\, are theoretically well-motivated\, pr
 oviding an elegant solution to the strong CP problem\, while a plethora of
  other axion-like fields arise naturally in theories with extra dimensions
 . Such fields have couplings to the electromagnetic sector\, offering an e
 xciting opportunity to constrain high-energy physics using astrophysical p
 hotons in the late universe. I will discuss how distance determinations in
  cosmology (coming from supernova observations\, measurements of cosmic ex
 pansion\, and baryon acoustic oscillations) can be used to place strong co
 nstraints on axion-like particles through distance duality tests. Similar 
 techniques apply to any scalar field coupling to photons\, including dark 
 energy. I will point out additional effects of scalar-photon couplings on 
 the CMB temperature evolution\, that could be used to break degeneracies i
 n dark energy parameter estimations. 
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
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