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VERSION:2.0
PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN
BEGIN:VEVENT
SUMMARY:Causality constraints on K-essence: Superfluid dark matter to modi
 fied gravity
DTSTART:20230620T143000Z
DTEND:20230620T160000Z
DTSTAMP:20260731T184835Z
UID:6ea621df-e205-4c8a-88c5-0ef3c3f07921
SEQUENCE:1
CREATED:20230616T110435Z
DESCRIPTION: ABSTRACT: Superfluid dark matter is a novel way of reconcilin
 g the apparent discrepancy between galactic phenomenology and LCDM cosmolo
 gy. The advantage of these models is that on cosmological scales they can 
 play the role of CDM\, while on galactic scales there is a phase transitio
 n to a superfluid\, and the nontrivial dynamics in this regime can reprodu
 ce the observed Tully-Fisher relation. However\, we find in general these 
 models exhibit a breakdown of causality\, which indicates they would resis
 t having any standard UV completion. Constructing a class of causal k-esse
 nce theories\, instead of dark matter we can consider these as scalar modi
 fications of gravity. In these theories the strength of the new force grow
 s with increasing density\, becoming most relevant in the densest astrophy
 sical environments. We consider various observational constraints on this 
 class of modified gravity theories\, with the strongest constraint coming 
 from equilibrium of neutron stars.  
LAST-MODIFIED:20230616T110435Z
LOCATION:Sala de Seminários do DF\,  Pavilhão de Física\, 2º piso
URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/causality-constraints-on-k
 -essence-superfluid-dark-matter-to-modified-gravity/
X-ALT-DESC;FMTTYPE=text/html:<p data-block-key="w97pf"> ABSTRACT: Superflu
 id dark matter is a novel way of reconciling the apparent discrepancy betw
 een galactic phenomenology and LCDM cosmology. The advantage of these mode
 ls is that on cosmological scales they can play the role of CDM\, while on
  galactic scales there is a phase transition to a superfluid\, and the non
 trivial dynamics in this regime can reproduce the observed Tully-Fisher re
 lation. </p><p data-block-key="e1obk"></p><p data-block-key="chcoo">Howeve
 r\, we find in general these models exhibit a breakdown of causality\, whi
 ch indicates they would resist having any standard UV completion. Construc
 ting a class of causal k-essence theories\, instead of dark matter we can 
 consider these as scalar modifications of gravity. </p><p data-block-key="
 ecea9"></p><p data-block-key="b2men">In these theories the strength of the
  new force grows with increasing density\, becoming most relevant in the d
 ensest astrophysical environments. We consider various observational const
 raints on this class of modified gravity theories\, with the strongest con
 straint coming from equilibrium of neutron stars.  </p>
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