Evolution of primordial black holes in f(Q) gravity with non-linear equation of state

Abstract

Abstract We study evolution of primordial black holes (PBH) in the f ( Q ) modified gravity for matter accretion from the cosmic fluid surrounding the PBH. For matter described by non-linear equation of state $$p=f(\rho )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mo>=</mml:mo> <mml:mi>f</mml:mi> <mml:mo>(</mml:mo> <mml:mi>ρ</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , the accretion of matter in PBH is probed. Two different branches of non-linear EoS is considered here namely, (i) modified Chaplygin gas (MCG) and (ii) viscous fluid in addition to barotropic fluid. We also probe the EoS needed for the emergent universe which admits different compositions of the cosmic fluid surrounding the black hole to probe the evolution and then compared the evolutionary features for the other polynomial form of the EoS. In f ( Q ) modified gravity, primordial black holes are found to gain mass in the early epoch which finally attains a saturated mass. The picture is different from that of GR as well as $$f(\mathcal {T})$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>f</mml:mi> <mml:mo>(</mml:mo> <mml:mi>T</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> gravity. We have also compared the PBH evolution in f ( Q )-gravity with or without the MCG.