Abstract <p>Twisted space-times are logical extensions of Friedmann cosmological models, Lorentz–Minkowski space-times, Einstein-de Sitter space-times, generalized Robertson–Walker (GRW) space-times, and static Einstein space-times. The purpose of this manuscript is to investigate the characteristics of twisted space-times that are almost pseudo-Ricci symmetric (briefly, A(PRS)<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m1--> </InlineEquation>). We establish the sufficient conditions under which A(PRS)<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m2--> </InlineEquation> twisted space-times are GRW space-times, and under which A(PRS)<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m3--> </InlineEquation> space-times are twisted space-times. The necessary and sufficient condition for A(PRS)<InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m4--> </InlineEquation> twisted space-times to be perfect fluid space-times is derived. We also prove that the vorticity and shear of A(PRS)<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m5--> </InlineEquation> twisted space-times filled with perfect fluid vanish identically. Consequently, we establish the equation of state and energy conditions. The non-existence of Ricci symmetric A(PRS)<InlineEquation ID="IEq6"> <EquationSource Format="TEX">\({}_{n}\)</EquationSource> <!--GravCos2570054De-m6--> </InlineEquation> twisted space-times is ensured.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

A Note on Twisted Spacetimes

  • Uday Chand De,
  • Sudhakar Kumar Chaubey

摘要

Abstract

Twisted space-times are logical extensions of Friedmann cosmological models, Lorentz–Minkowski space-times, Einstein-de Sitter space-times, generalized Robertson–Walker (GRW) space-times, and static Einstein space-times. The purpose of this manuscript is to investigate the characteristics of twisted space-times that are almost pseudo-Ricci symmetric (briefly, A(PRS) \({}_{n}\) ). We establish the sufficient conditions under which A(PRS) \({}_{n}\) twisted space-times are GRW space-times, and under which A(PRS) \({}_{n}\) space-times are twisted space-times. The necessary and sufficient condition for A(PRS) \({}_{n}\) twisted space-times to be perfect fluid space-times is derived. We also prove that the vorticity and shear of A(PRS) \({}_{n}\) twisted space-times filled with perfect fluid vanish identically. Consequently, we establish the equation of state and energy conditions. The non-existence of Ricci symmetric A(PRS) \({}_{n}\) twisted space-times is ensured.