Madrid's Polygonal Gravity Seminar Series

10:30h First talk

Speaker: Mariam Bouhmadi Lopez (UPV/EHU)

Title: Speeding up the Universe

Abstract: We are currently living an outstanding time in the field of cosmology 
and gravitation where more and more data are being collected constantly. One of 
the most puzzling questions that we cosmologists are facing nowadays is the 
mysterious source that is driving our recent acceleration. One of the most 
accepted explanations for this phenomenon is a dark energy (DE) component. In 
the current talk, we present several DE models ranging from perfect fluid, 
imperfect fluid, scalar fields to 3-forms. We present observational constraints 
on them.  We will as well address the $H_0$ and $S_8$ tensions. For those 
models that show a phantom or a phantom-like behaviour; i.e. where some energy 
condition violations take place, it can be shown their harmlessness from a 
quantum point of view, i.e. the singularities or abrupt events they might 
induce are "cured" at the quantum level.

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11:30 Coffee break

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12:00h Second talk

Speaker: P.K. Townsend (Cambridge U.)

Title: Nonlinear Electrodynamics re-Born

Abstract: Nonlinear Electrodynamics (NLED) was born more than 90 years ago. 
Some old, not-so old, and some recent results on this topic will be reviewed 
and/or explained. The general theory will be developed from the macroscopic 
Maxwell equations, and topics covered will include self-duality, conformal 
limits, birefringence and causality. Examples, such as Born’s original model, 
the Born-Infeld (BI) theory, Bialynicki-Birula’s ``photon dust’’, and ModMax 
will be used to illustrate the themes discussed.  Some String/M-Theory 
motivations may be mentioned.

More information about these and following monthly seminars can be found at the
webpage

https://sites.google.com/view/polygrav

We very much hope to see you there! (No registration is needed)

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