Akademik Veri Yönetim Sistemi
Yeni Yüzyıl Üniversitesi 9. Bilim Günleri Kongresi, İstanbul, Türkiye, 9 - 11 Mayıs 2023, ss.70, (Özet Bildiri)
The study of the phenomenon of creating particles due to the gravitational field has been an area of intense interest lately. It is thought to be able to solve the cosmological puzzle alone, without the need for dark energy or a modified theory of gravity. In the early universe, it serves the purpose of reheating the cold universe, which, following gracefully exiting the inflation stage, gives rise to the hot Big-Bang pattern. A flat Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological model with perfect fluid comprising of Chaplygin gas has been studied with particle creation. The solution of the field equations are obtained two different considered form of scale factors. The effective pressure is negative throughout the evolution of universe, which leads to accelerated expansion of the universe. As noted, the thermodynamics of the standard model was developed under the assumption of reversibility and adiabaticity. The entropy density 𝑠 can be derived via the second law of thermodynamics 𝑑𝐸 = 𝑇𝑑𝑆 − 𝑃𝑑𝑉, where 𝑉 ∝ 𝑎 3 (𝑎 is the scale factor) is a volume moving with energy 𝐸 = 𝜌𝑉 and entropy 𝑆 =𝑠. This can be expressed as 𝑑𝜌 = (𝑠𝑇 − 𝜌 −𝑃)𝑑𝑉/ 𝑉+ 𝑇𝑑𝑠. And since 𝜌 depends on 𝑇, equation implies that, 𝑠 =𝜌+𝑃/𝑇. So the total entropy remains constant for the reversible adiabatic universe.