Collapse in f(R) gravity and the method of R matching
Abstract Collapsing solutions in f(R) gravity are restricted due to junction conditions that demand continuity of the Ricci scalar and its normal derivative across the time-like collapsing hypersurface. These are obtained via the method of R-matching, which is ubiquitous in f(R) collapse scenarios....
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2020-09-01
|
| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | http://link.springer.com/article/10.1140/epjc/s10052-020-08459-w |
| _version_ | 1819021770024288256 |
|---|---|
| author | Sandip Chowdhury Kunal Pal Kuntal Pal Tapobrata Sarkar |
| author_facet | Sandip Chowdhury Kunal Pal Kuntal Pal Tapobrata Sarkar |
| author_sort | Sandip Chowdhury |
| collection | DOAJ |
| description | Abstract Collapsing solutions in f(R) gravity are restricted due to junction conditions that demand continuity of the Ricci scalar and its normal derivative across the time-like collapsing hypersurface. These are obtained via the method of R-matching, which is ubiquitous in f(R) collapse scenarios. In this paper, we study spherically symmetric collapse with the modification term $$\alpha R^2$$ α R 2 , and use R-matching to exemplify a class of new solutions. After discussing some mathematical preliminaries by which we obtain an algebraic relation between the shear and the anisotropy in these theories, we consider two metric ansatzes. In the first, the collapsing metric is considered to be a separable function of the co-moving radius and time, and the collapse is shear-free, and in the second, a non-separable interior solution is considered, that represents gravitational collapse with non-zero shear viscosity. We arrive at novel solutions that indicate the formation of black holes or locally naked singularities, while obeying all the necessary energy conditions. The separable case allows for a simple analytic expression of the energy-momentum tensor, that indicates the positivity of the pressures throughout collapse, and is further used to study the heat flux evolution of the collapsing matter, whose analytic solutions are presented under certain approximations. These clearly highlight the role of modified gravity in the examples that we consider. |
| first_indexed | 2024-12-21T04:12:23Z |
| format | Article |
| id | doaj.art-7ccd10db071f4b8ca210ba6e1916886f |
| institution | Directory Open Access Journal |
| issn | 1434-6044 1434-6052 |
| language | English |
| last_indexed | 2024-12-21T04:12:23Z |
| publishDate | 2020-09-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-7ccd10db071f4b8ca210ba6e1916886f2022-12-21T19:16:24ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522020-09-0180911510.1140/epjc/s10052-020-08459-wCollapse in f(R) gravity and the method of R matchingSandip Chowdhury0Kunal Pal1Kuntal Pal2Tapobrata Sarkar3Department of Physics, Indian Institute of TechnologyDepartment of Physics, Indian Institute of TechnologyDepartment of Physics, Indian Institute of TechnologyDepartment of Physics, Indian Institute of TechnologyAbstract Collapsing solutions in f(R) gravity are restricted due to junction conditions that demand continuity of the Ricci scalar and its normal derivative across the time-like collapsing hypersurface. These are obtained via the method of R-matching, which is ubiquitous in f(R) collapse scenarios. In this paper, we study spherically symmetric collapse with the modification term $$\alpha R^2$$ α R 2 , and use R-matching to exemplify a class of new solutions. After discussing some mathematical preliminaries by which we obtain an algebraic relation between the shear and the anisotropy in these theories, we consider two metric ansatzes. In the first, the collapsing metric is considered to be a separable function of the co-moving radius and time, and the collapse is shear-free, and in the second, a non-separable interior solution is considered, that represents gravitational collapse with non-zero shear viscosity. We arrive at novel solutions that indicate the formation of black holes or locally naked singularities, while obeying all the necessary energy conditions. The separable case allows for a simple analytic expression of the energy-momentum tensor, that indicates the positivity of the pressures throughout collapse, and is further used to study the heat flux evolution of the collapsing matter, whose analytic solutions are presented under certain approximations. These clearly highlight the role of modified gravity in the examples that we consider.http://link.springer.com/article/10.1140/epjc/s10052-020-08459-w |
| spellingShingle | Sandip Chowdhury Kunal Pal Kuntal Pal Tapobrata Sarkar Collapse in f(R) gravity and the method of R matching European Physical Journal C: Particles and Fields |
| title | Collapse in f(R) gravity and the method of R matching |
| title_full | Collapse in f(R) gravity and the method of R matching |
| title_fullStr | Collapse in f(R) gravity and the method of R matching |
| title_full_unstemmed | Collapse in f(R) gravity and the method of R matching |
| title_short | Collapse in f(R) gravity and the method of R matching |
| title_sort | collapse in f r gravity and the method of r matching |
| url | http://link.springer.com/article/10.1140/epjc/s10052-020-08459-w |
| work_keys_str_mv | AT sandipchowdhury collapseinfrgravityandthemethodofrmatching AT kunalpal collapseinfrgravityandthemethodofrmatching AT kuntalpal collapseinfrgravityandthemethodofrmatching AT tapobratasarkar collapseinfrgravityandthemethodofrmatching |