### Abstract

A flat Friedmann universe filled with a mixture of anti-Chaplygin gas and dust-like matter evolves into a future soft singularity, where despite infinite tidal forces the geodesics can be continued. In the singularity the pressure of the anti-Chaplygin gas diverges, while its energy density is zero. The dust energy density however does not vanish, neither does the Hubble parameter, which implies further expansion, if its evolution is to be continuous. If so, the energy density and the pressure of the anti-Chaplygin gas would become ill-defined, hence only a contraction would be allowed. Paradoxically, the universe in this cosmological model would have to expand and contract simultaneously. The paradox can be avoided by redefining the anti-Chaplygin gas in a distributional sense. Then the Hubble parameter could be mirrored to have a jump at the singularity, allowing for a subsequent contraction. With this modification the set of Friedmann, Raychaudhuri and continuity equations are all obeyed both at the singularity and in its vicinity.

Original language | English |
---|---|

Title of host publication | On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories |

Editors | Kjell Rosquist, Robert T. Jantzen, Remo Ruffini, Remo Ruffini |

Publisher | World Scientific |

Pages | 1847-1849 |

Number of pages | 3 |

Edition | 210699 |

ISBN (Print) | 9789814612142 |

DOIs | |

Publication status | Published - Jan 1 2015 |

Event | 13th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation, and Relativistic Field Theories, MG13 2012 - Stockholm, Sweden Duration: Jul 1 2015 → Jul 7 2015 |

### Publication series

Name | The 13th Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proceedings of the MG13 Meeting on General Relativity, 2012 |
---|---|

Number | 210699 |

### Other

Other | 13th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation, and Relativistic Field Theories, MG13 2012 |
---|---|

Country | Sweden |

City | Stockholm |

Period | 7/1/15 → 7/7/15 |

### Keywords

- Anti-Chaplygin gas
- Distributions
- Singularity

### ASJC Scopus subject areas

- Nuclear and High Energy Physics

## Fingerprint Dive into the research topics of 'The paradox of soft singularity crossing avoided by distributional cosmological quantities'. Together they form a unique fingerprint.

## Cite this

*On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories*(210699 ed., pp. 1847-1849). (The 13th Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proceedings of the MG13 Meeting on General Relativity, 2012; No. 210699). World Scientific. https://doi.org/10.1142/9789814623995_0295