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SUMMARY:Solid matter with zero shear modulus in flat universe
DTSTART;VALUE=DATE-TIME:20210901T154500Z
DTEND;VALUE=DATE-TIME:20210901T160000Z
DTSTAMP;VALUE=DATE-TIME:20260808T000923Z
UID:indico-contribution-15691@indico.ific.uv.es
DESCRIPTION:Speakers: Peter Mészáros (Department of Theoretical Physics\
 , Comenius University in Bratislava\, Slovakia)\nFor a perfect fluid\, the
  quantity defined through mixed components of the stress-energy tensor $\\
 widetilde{w}=(T_{i}^{\\phantom{i}i}/3)/(-T_{0}^{\\phantom{0}0})$ is indepe
 ndent on the choice of coordinates only for two values of the pressure to 
 energy density ratio $w=p/\\rho$: for radiation with $w=1/3$\, and for dar
 k energy with $w=-1$. With other choices of $w$\, the quantity $\\widetild
 e{w}$ is coordinate dependent\, and $\\widetilde{w}=w$ only in the local r
 est frame of the fluid. We show that the same is true also for solid matte
 r with shear stress Lamé coefficient set to zero in a flat Friedmann-Lema
 itre-Robertson-Walker universe with perturbed metric as well as stress-ene
 rgy tensor. We call the two different solids with coordinate independent $
 \\widetilde{w}$ radiation-like solid and dark energy-like solid\, and we r
 estrict ourselves to these two special cases. By analysing second order pe
 rturbations we discover two one parametric sets of such solid matter model
 s containing special cases of radiation and dark energy as perfect fluids.
  We also study equations for perturbations up to the second order for both
  sets of models.\n\nhttps://indico.ific.uv.es/event/6178/contributions/156
 91/
LOCATION:
URL:https://indico.ific.uv.es/event/6178/contributions/15691/
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