BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Post-Maxwellian electrodynamics with neutron stars DTSTART:20250306T143000Z DTEND:20250306T160000Z DTSTAMP:20260731T131017Z UID:ace70c0a-1094-4fde-b9cc-7198d91497f5 SEQUENCE:1 CREATED:20250306T102529Z DESCRIPTION: One of the big\, open problems in gravity is whether or not b lack holes have singularities. In vacuum general relativity this is guaran teed via the Hawking-Penrose theorems\, but by coupling to various nonline ar\, electromagnetic Lagrangians it has been shown that charge may regular ise the object.Physically\, this is argued to be because gravity is attrac tive and electrostatics repulsive\, preventing singularities. Some highly- magnetised neutron stars ("\;magnetars"\;) have inferred polar fie ld strengths well in excess of the Schwinger limit\, where nonlinear elect romagnetic effects may dominate. Their internal fields may be even stronge r\, meaning that Maxwellian descriptions of hydromagnetic structure may re quire revision. In Born-Infeld-like theories -- a popular candidate for re gularizing holes -- I argue that the toroidal field has a maximum strength set by the scale parameter. Because of this\, there is an implicit bound to the stellar prolateness which can be inferred via gravitational waves\; detections or non-detections can thus be used to set bounds on post-Maxwe llian parameters that is competitive with terrestrial experiments. Connect ions with black hole singularitieswill then be made. LAST-MODIFIED:20250306T102529Z LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building URL:http://df.vps.tecnico.ulisboa.pt/en/events/post-maxwellian-electrodyna mics-with-neutron-stars/ X-ALT-DESC;FMTTYPE=text/html:

One of the big\, o pen problems in gravity is whether or not black holes have singularities. In vacuum general relativity this is guaranteed via the Hawking-Penrose th eorems\, but by coupling to various nonlinear\, electromagnetic Lagrangian s it has been shown that charge may regularise the object.

Physic ally\, this is argued to be because gravity is attractive and electrostati cs repulsive\, preventing singularities. Some highly-magnetised neutron st ars ("\;magnetars"\;) have inferred polar field strengths well in excess of the Schwinger limit\, where nonlinear electromagnetic effects ma y dominate. Their internal fields may be even stronger\, meaning that Maxw ellian descriptions of hydromagnetic structure may require revision.

In Born-Infeld-like theories -- a popular candidate for regularizing holes -- I argue that the toroidal field has a maximum strength set by the scale parameter. Because of this\, there is an implicit bound to the stel lar prolateness which can be inferred via gravitational waves\; detections or non-detections can thus be used to set bounds on post-Maxwellian param eters that is competitive with terrestrial experiments. Connections with b lack hole singularities
will then be made.

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