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VERSION:2.0
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SUMMARY:Post-Maxwellian electrodynamics with neutron stars
DTSTART:20250306T143000Z
DTEND:20250306T160000Z
DTSTAMP:20260725T114319Z
UID:ace70c0a-1094-4fde-b9cc-7198d91497f5
SEQUENCE:2
CREATED:20250306T102538Z
DESCRIPTION:One of the big\, open problems in gravity is whether or not bl
 ack holes have singularities. In vacuum general relativity this is guarant
 eed via the Hawking-Penrose theorems\, but by coupling to various nonlinea
 r\, electromagnetic Lagrangians it has been shown that charge may regulari
 se the object.Physically\, this is argued to be because gravity is attract
 ive and electrostatics repulsive\, preventing singularities. Some highly-m
 agnetised neutron stars (&quot\;magnetars&quot\;) have inferred polar fiel
 d strengths well in excess of the Schwinger limit\, where nonlinear electr
 omagnetic effects may dominate. Their internal fields may be even stronger
 \, meaning that Maxwellian descriptions of hydromagnetic structure may req
 uire revision. In Born-Infeld-like theories -- a popular candidate for reg
 ularizing holes -- I argue that the toroidal field has a maximum strength 
 set by the scale parameter. Because of this\, there is an implicit bound t
 o the stellar prolateness which can be inferred via gravitational waves\; 
 detections or non-detections can thus be used to set bounds on post-Maxwel
 lian parameters that is competitive with terrestrial experiments. Connecti
 ons with black hole singularitieswill then be made.
LAST-MODIFIED:20250306T102552Z
LOCATION:DF Seminar Room (2-8.3)\, 2nd floor of Physics Building
URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/post-maxwellian-electrodyn
 amics-with-neutron-stars/
X-ALT-DESC;FMTTYPE=text/html:<p data-block-key="3swrd">One of the big\, op
 en problems in gravity is whether or not black holes have singularities. I
 n vacuum general relativity this is guaranteed via the Hawking-Penrose the
 orems\, but by coupling to various nonlinear\, electromagnetic Lagrangians
  it has been shown that charge may regularise the object.<br/><br/>Physica
 lly\, this is argued to be because gravity is attractive and electrostatic
 s repulsive\, preventing singularities. Some highly-magnetised neutron sta
 rs (&quot\;magnetars&quot\;) have inferred polar field strengths well in e
 xcess of the Schwinger limit\, where nonlinear electromagnetic effects may
  dominate. Their internal fields may be even stronger\, meaning that Maxwe
 llian descriptions of hydromagnetic structure may require revision.<br/><b
 r/> In Born-Infeld-like theories -- a popular candidate for regularizing h
 oles -- 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 stell
 ar prolateness which can be inferred via gravitational waves\; detections 
 or non-detections can thus be used to set bounds on post-Maxwellian parame
 ters that is competitive with terrestrial experiments. Connections with bl
 ack hole singularities<br/>will then be made.<br/></p>
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