Fluid dynamics in the warp drive spacetime geometry

Osvaldo Santos-Pereira (Physics Institute, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil) ; Everton Abreu (Physics Department, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil; Physics Department, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil; Graduate Program in Applied Physics, Physics Institute, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil) ; Marcelo Ribeiro (Physics Institute, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Applied Physics, Physics Institute, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Valongo Observatory, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil)

The Alcubierre warp drive metric is a spacetime geometry featuring a spacetime distortion, called a warp bubble, where a massive particle inside it acquires global superluminal velocities, or warp speeds. This work presents solutions of the Einstein equations for the Alcubierre metric having fluid matter as gravity source. The energy–momentum tensor considered has two fluid contents, the perfect fluid and the parametrized perfect fluid (PPF), a tentative more flexible model whose aim is to explore the possibilities of warp drive solutions with positive matter density content. Santos-Pereira et al. (Eur Phys J C 80:786, 2020) already showed that the Alcubierre metric having dust as source connects this geometry to the Burgers equation, which describes shock waves moving through an inviscid fluid, but led the solutions back to vacuum. The same happened for two out of four solutions subcases for the perfect fluid. Other solutions for the perfect fluid indicate the possibility of warp drive with positive matter density, but at the cost of a complex solution for the warp drive regulating function. Regarding the PPF, solutions were also obtained indicating that warp speeds could be created with positive matter density. Weak, dominant, strong and null energy conditions were calculated for all studied subcases, being satisfied for the perfect fluid and creating constraints in the PPF quantities such that a positive matter density is also possible for creating a warp bubble. Summing up all results, energy–momentum tensors describing more complex forms of matter or field distributions generate solutions for the Einstein equations with the warp drive metric where a negative matter density might not be a strict precondition for attaining warp speeds.

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      "value": "The Alcubierre warp drive metric is a spacetime geometry featuring a spacetime distortion, called a warp bubble, where a massive particle inside it acquires global superluminal velocities, or warp speeds. This work presents solutions of the Einstein equations for the Alcubierre metric having fluid matter as gravity source. The energy\u2013momentum tensor considered has two fluid contents, the perfect fluid and the parametrized perfect fluid (PPF), a tentative more flexible model whose aim is to explore the possibilities of warp drive solutions with positive matter density content. Santos-Pereira et al. (Eur Phys J C 80:786, 2020) already showed that the Alcubierre metric having dust as source connects this geometry to the Burgers equation, which describes shock waves moving through an inviscid fluid, but led the solutions back to vacuum. The same happened for two out of four solutions subcases for the perfect fluid. Other solutions for the perfect fluid indicate the possibility of warp drive with positive matter density, but at the cost of a complex solution for the warp drive regulating function. Regarding the PPF, solutions were also obtained indicating that warp speeds could be created with positive matter density. Weak, dominant, strong and null energy conditions were calculated for all studied subcases, being satisfied for the perfect fluid and creating constraints in the PPF quantities such that a positive matter density is also possible for creating a warp bubble. Summing up all results, energy\u2013momentum tensors describing more complex forms of matter or field distributions generate solutions for the Einstein equations with the warp drive metric where a negative matter density might not be a strict precondition for attaining warp speeds."
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Published on:
06 February 2021
Publisher:
Springer
Published in:
European Physical Journal C , Volume 81 (2021)
Issue 2
Pages 1-22
DOI:
https://doi.org/10.1140/epjc/s10052-021-08921-3
Copyrights:
The Author(s)
Licence:
CC-BY-4.0

Fulltext files: