报告题目：Constraining Scalar-Photon Couplings with Cosmological Observations
报告人简介：2003-2006: PhD in Theoretical Cosmology, University of Cambridge, UK;
2006–2008: Marie-Curie RTN Postdoctoral Position, University of Barcelona, Spain;
2009–2011: CTC Research Fellow, University of Cambridge, UK;
2011–2013: Marie-Curie Research Fellow, University of Nottingham, UK;
2013–present: Nottingham Advanced Research Fellow, University of Nottingham, UK.
报告摘要：Scalar and pseudoscalar fields are generically present in fundamental theories of the early universe. Axions, for example, provide an elegant solution to the strong CP problem, while other axion-like (pseudo)scalars arise naturally in theories with extra dimensions. Such fields have couplings to the electromagnetic sector, providing an exciting opportunity to constrain high-energy physics using astrophysical photons in the observable universe. In particular, scalar-photon couplings induce deviations from the standard distance-duality relation and I will discuss how distance determinations in cosmology can be used to obtain strong constraints on axion-like particles. Similar techniques also apply to other scalar fields like those invoked in evolving Dark Energy models. For such cases, I will point out additional effects on the CMB temperature evolution T(z), which are parametrically related to distance-duality deviations and can thus be used to break degeneracies in Dark Energy parameter estimations. I will also present the latest constraints on T(z) and discuss their implications.