Théorie

New model of the coherent magnetic halo of the Milky Way

Recent catalog of Faraday rotation measures (RM) of extragalactic sources together with the synchrotron polarization data from WMAP and Planck provide us with the wealth of information on the Galactic magnetic field (GMF). In this talk, we will present a new model of the regular GMF outside of the thin disk. The model is based on several phenomenological components of the GMF -- the spiral arms, the toroidal halo, the X-shaped field and the compressed field of the Local Bubble wall.

Love numbers beyond GR and non-linear scalar tidal deformation

In General Relativity (GR), including Einstein-Maxwell theory, it is remarkable that all asymptotically flat black hole (BH) solutions have vanishing Love numbers. Consequently, the Love numbers of BHs present an excellent opportunity to examine any deviations from GR. We will investigate tidal deformations concerning neutral BHs and extremal BHs in EFT of gravity. In four dimensions, the primary contribution to the tidal Love numbers of neutral BHs arises from six derivative operators, while the Love numbers of extremal BHs are subject to corrections from four derivative operators.

Positivity bounds on electromagnetic properties of media

I will talk about the constraints imposed on the electromagnetic response of general media by microcausality (commutators of local fields vanish outside the light cone) and positivity of the imaginary parts (the medium can only absorb energy from the external field). The effect of the medium is encoded in the electric and magnetic permeabilities ε(ω, k) and μ(ω, k). In the case of dielectrics, we obtain bounds on the low-energy values of the response, ε(0, 0) and μ(0, 0).

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