In this article, we examine gradient type Ricci solitons and -quasi Einstein solitons in generalized Robertson-Walker (GRW) spacetimes. Besides, we demonstrate that in this scenario the GRW spacetime presents the Robertson-Walker (RW) spacetime and the perfect fluid (PF) spacetime presents the phantom era. Consequently, we show that if a GRW spacetime permits a gradient τ-Einstein solitons, then it also represents a PF spacetime under certain condition.
Keywords: 53C50; 53Z05; 83C05; Differential equations; Generalized Robertson-Walker spacetime; Gradient -quasi Einstein soliton; Gradient Ricci soliton; Nonlinear equations; Partial differential equations.
© 2024 The Author(s).