Chaplygin gas, which occurs in certain theories of cosmology, is a hypothetical substance that satisfies an exotic equation of state in the form
p = − A / ρ α {\displaystyle p=-A/\rho ^{\alpha }} , where p {\displaystyle p} is the pressure, ρ {\displaystyle \rho } is the density, with α = 1 {\displaystyle \alpha =1} and A {\displaystyle A} a positive constant. The substance is named after Sergey Chaplygin. In some models, generalized Chaplygin gas is considered, where α {\displaystyle \alpha } is a parameter, which can take on values 0 < α ≤ 1 {\displaystyle 0<\alpha \leq 1} . A slowly rotating spherically symmetric, non-viscous, self-gravitating Chapligin gas solves the Hubble tension.
See also
Dark fluid
References