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Cosmological Evolution: A Study of Transition Periods
Research Article | Published: 23 November 2025
Journal of Numerical Simulations in Physics and Mathematics Volume 1, Issue 2, 2025: 67-75
Volume 1, Issue 2, Journal of Numerical Simulations in Physics and Mathematics
Volume 1, Issue 2, 2025
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Journal of Numerical Simulations in Physics and Mathematics, Volume 1, Issue 2, 2025: 67-75

Open Access | Research Article | 23 November 2025
Cosmological Evolution: A Study of Transition Periods
by
Bob Osano Bob Osano 1,2 *
1 Cosmology and Gravity Group, Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, South Africa
2 Centre for Higher Education Development, University of Cape Town, Rondebosch 7701, South Africa
* Corresponding Author: Bob Osano, [email protected]
DOI: 10.62762/JNSPM.2025.159712
ARK: ark:/57805/jnspm.2025.159712
Received: 09 September 2025, Accepted: 18 September 2025, Published: 23 November 2025  
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Abstract
This study investigates two transitions in cosmology: radiation-matter and matter-dark energy. For each transition, a parameter $\chi$ is employed, representing the ratio of the two energy densities involved in the relevant transition. The focus on the second transition is motivated by the need to understand an accelerating universe. In examining potential cosmic acceleration due to dynamic dark energy, a dynamical equation of state for dark energy is considered in terms of the ratio $\chi$ and the deceleration parameter $q$. The resulting system of equations is analyzed by varying parameters to investigate their influence on the evolution of the universe. To achieve cosmic acceleration, the equation of state for dynamic dark energy (denoted $\omega$) must satisfy $\omega<-2/3$ at the matter-dark energy transition, corresponding to $\omega<-0.47$ at present.
Graphical Abstract
Cosmological Evolution: A Study of Transition Periods
Keywords
cosmological transitions
dark energy dynamics
deceleration parameter
friedmann equations
equation of state
Data Availability Statement
Data will be made available on request.
Funding
This work was supported by the University of Cape Town’s NGP.
Conflicts of Interest
The author declares no conflicts of interest.
Ethical Approval and Consent to Participate
Not applicable.
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APA Style
Osano, B. (2025). Cosmological Evolution: A Study of Transition Periods. Journal of Numerical Simulations in Physics and Mathematics, 1(2), 67–75. https://doi.org/10.62762/JNSPM.2025.159712
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TY  - JOUR
AU  - Osano, Bob
PY  - 2025
DA  - 2025/11/23
TI  - Cosmological Evolution: A Study of Transition Periods
JO  - Journal of Numerical Simulations in Physics and Mathematics
T2  - Journal of Numerical Simulations in Physics and Mathematics
JF  - Journal of Numerical Simulations in Physics and Mathematics
VL  - 1
IS  - 2
SP  - 67
EP  - 75
DO  - 10.62762/JNSPM.2025.159712
UR  - https://www.icck.org/article/abs/JNSPM.2025.159712
KW  - cosmological transitions
KW  - dark energy dynamics
KW  - deceleration parameter
KW  - friedmann equations
KW  - equation of state
AB  - This study investigates two transitions in cosmology: radiation-matter and matter-dark energy. For each transition, a parameter $\chi$ is employed, representing the ratio of the two energy densities involved in the relevant transition. The focus on the second transition is motivated by the need to understand an accelerating universe. In examining potential cosmic acceleration due to dynamic dark energy, a dynamical equation of state for dark energy is considered in terms of the ratio $\chi$ and the deceleration parameter $q$. The resulting system of equations is analyzed by varying parameters to investigate their influence on the evolution of the universe. To achieve cosmic acceleration, the equation of state for dynamic dark energy (denoted $\omega$) must satisfy $\omega
SN  - 3068-9082
PB  - Institute of Central Computation and Knowledge
LA  - English
ER  -
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@article{Osano2025Cosmologic,
  author = {Bob Osano},
  title = {Cosmological Evolution: A Study of Transition Periods},
  journal = {Journal of Numerical Simulations in Physics and Mathematics},
  year = {2025},
  volume = {1},
  number = {2},
  pages = {67-75},
  doi = {10.62762/JNSPM.2025.159712},
  url = {https://www.icck.org/article/abs/JNSPM.2025.159712},
  abstract = {This study investigates two transitions in cosmology: radiation-matter and matter-dark energy. For each transition, a parameter \$\chi\$ is employed, representing the ratio of the two energy densities involved in the relevant transition. The focus on the second transition is motivated by the need to understand an accelerating universe. In examining potential cosmic acceleration due to dynamic dark energy, a dynamical equation of state for dark energy is considered in terms of the ratio \$\chi\$ and the deceleration parameter \$q\$. The resulting system of equations is analyzed by varying parameters to investigate their influence on the evolution of the universe. To achieve cosmic acceleration, the equation of state for dynamic dark energy (denoted \$\omega\$) must satisfy \$\omega},
  keywords = {cosmological transitions, dark energy dynamics, deceleration parameter, friedmann equations, equation of state},
  issn = {3068-9082},
  publisher = {Institute of Central Computation and Knowledge}
}
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