Wormhole formation in f(R,T) gravity: Varying Chaplygin gas and barotropic fluid

作     者：Emilio Elizalde Martiros Khurshudyan 

作者机构：Consejo Superior de Investigaciones Científicas ICE/CSIC-IEEC Campus UAB Carrer de Can Magrans s/n 08193 Bellaterra (Barcelona) Spain International Laboratory for Theoretical Cosmology Tomsk State University of Control Systems and Radioelectronics (TUSUR) 634050 Tomsk Russia Research Division Tomsk State Pedagogical University 634061 Tomsk Russia CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei 230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei 230026 China 

出 版 物：《Physical Review D》 (Phy. Rev. D)

年 卷 期：2018年第98卷第12期

页      面：123525-123525页

核心收录：

基　　金：Chinese Academy of Sciences, CAS, (2018PM0054) Chinese Academy of Sciences, CAS Generalitat de Catalunya, (2017-SGR-247) Generalitat de Catalunya Ministerio de Economía y Competitividad, MINECO, (FIS2016-76363-P) Ministerio de Economía y Competitividad, MINECO 

主　　题：Alternative gravity theories Evolution of the Universe General relativity equations & solutions 

摘      要：In this paper, the formation of specific static wormhole models is discussed, by assuming an f(R,T)=R+2λT extended theory of gravity, T=−ρ+Pr+2Pl being the trace of the energy momentum tensor. In the first part, wormhole solutions are constructed imposing that the radial pressure admits an equation of state corresponding to a varying Chaplygin gas. Two forms for the varying Chaplygin gas are considered, namely Pr=−Bb(r)u/ρα and Pr=−BR(r)m/ρα, respectively. In the second part, the wormhole models are constructed assuming that the radial pressure can be described by a varying barotropic fluid. In particular, Pr=ωb(r)vρ and Pr=ω^rkR(r)ηρ are considered, respectively, leading to two additional, traversable wormhole models. In all cases, b(r) is the shape function, and R(r) the Ricci scalar obtained from the wormhole metric for a redshift function equal to 1. With the help of specific examples, it is demonstrated that the shape functions of the exact wormhole models previously constructed do obey the necessary metric conditions. The same energy conditions help reveal the physical properties of these models. A general feature is the violation of the null energy condition (NEC) (ρ+Pi≥0) in terms of the radial pressure Pr at the throat of the wormhole. For some of the models, one can satisfy the NEC at the throat while a violation of the dominant energy condition (DEC) (ρ−Pi≥0) occurs. To summarize, exact wormhole models can be constructed with a possible violation of the NEC and DEC at the throat of the wormhole, while being ρ≥0. Thus, the interesting feature appears that one has a violation of the weak energy condition (ρ≥0 and ρ+Pi≥0) not related to the energy density behavior (the index i, being r respectively l, indicates radial respectively lateral pressure).