Exploring the expansion of the universe using the Grüneisen parameter
For a perfect fluid, pressure p and energy density ρ are related via the equation of state (EOS) ω=p/ρ, where ω is the EOS parameter, being its interpretation usually constrained to a numerical value for each universe era. Here, based on the Mie–Grüneisen EOS, we show that ω is recognized as the eff...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2024-02-01
|
| Series: | Results in Physics |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211379724000263 |
| _version_ | 1827349858507292672 |
|---|---|
| author | Lucas Squillante Gabriel O. Gomes Isys F. Mello Guilherme Nogueira Antonio C. Seridonio Roberto E. Lagos-Monaco Mariano de Souza |
| author_facet | Lucas Squillante Gabriel O. Gomes Isys F. Mello Guilherme Nogueira Antonio C. Seridonio Roberto E. Lagos-Monaco Mariano de Souza |
| author_sort | Lucas Squillante |
| collection | DOAJ |
| description | For a perfect fluid, pressure p and energy density ρ are related via the equation of state (EOS) ω=p/ρ, where ω is the EOS parameter, being its interpretation usually constrained to a numerical value for each universe era. Here, based on the Mie–Grüneisen EOS, we show that ω is recognized as the effective Grüneisen parameter Γeff, whose singular contribution, the so-called Grüneisen ratio Γ, quantifies the barocaloric effect. Our analysis suggests that the negative p associated with dark-energy implies a metastable state and that in the dark-energy-dominated era ω is time-dependent, which reinforces recent proposals of a time-dependent cosmological constant. Furthermore, we demonstrate that Γeff is embodied in the energy–momentum stress tensor in the Einstein field equations, enabling us to analyse, in the frame of an imperfect fluid picture, anisotropic effects of the universe expansion. We propose that upon going from decelerated- to accelerated-expansion, a phase transition-like behaviour can be inferred. Yet, our analysis in terms of entropy, Γ, and a by us adapted version of Avramov/Casalini’s model to Cosmology unveil hidden aspects related to the expansion of the universe. Our findings pave the way to interpret cosmological phenomena in connection with concepts of condensed matter Physics via Γeff. |
| first_indexed | 2024-03-08T00:50:18Z |
| format | Article |
| id | doaj.art-c0b1b357d23b4d868c281651b34d8fb0 |
| institution | Directory Open Access Journal |
| issn | 2211-3797 |
| language | English |
| last_indexed | 2024-03-08T00:50:18Z |
| publishDate | 2024-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Physics |
| spelling | doaj.art-c0b1b357d23b4d868c281651b34d8fb02024-02-15T05:23:41ZengElsevierResults in Physics2211-37972024-02-0157107344Exploring the expansion of the universe using the Grüneisen parameterLucas Squillante0Gabriel O. Gomes1Isys F. Mello2Guilherme Nogueira3Antonio C. Seridonio4Roberto E. Lagos-Monaco5Mariano de Souza6São Paulo State University (Unesp), IGCE - Physics Department, Rio Claro, SP, BrazilUniversity of São Paulo, Department of Astronomy, São Paulo, BrazilSão Paulo State University (Unesp), IGCE - Physics Department, Rio Claro, SP, BrazilSão Paulo State University (Unesp), IGCE - Physics Department, Rio Claro, SP, BrazilSão Paulo State University (Unesp), Department of Physics and Chemistry, Ilha Solteira, SP, BrazilSão Paulo State University (Unesp), IGCE - Physics Department, Rio Claro, SP, BrazilSão Paulo State University (Unesp), IGCE - Physics Department, Rio Claro, SP, Brazil; Corresponding author.For a perfect fluid, pressure p and energy density ρ are related via the equation of state (EOS) ω=p/ρ, where ω is the EOS parameter, being its interpretation usually constrained to a numerical value for each universe era. Here, based on the Mie–Grüneisen EOS, we show that ω is recognized as the effective Grüneisen parameter Γeff, whose singular contribution, the so-called Grüneisen ratio Γ, quantifies the barocaloric effect. Our analysis suggests that the negative p associated with dark-energy implies a metastable state and that in the dark-energy-dominated era ω is time-dependent, which reinforces recent proposals of a time-dependent cosmological constant. Furthermore, we demonstrate that Γeff is embodied in the energy–momentum stress tensor in the Einstein field equations, enabling us to analyse, in the frame of an imperfect fluid picture, anisotropic effects of the universe expansion. We propose that upon going from decelerated- to accelerated-expansion, a phase transition-like behaviour can be inferred. Yet, our analysis in terms of entropy, Γ, and a by us adapted version of Avramov/Casalini’s model to Cosmology unveil hidden aspects related to the expansion of the universe. Our findings pave the way to interpret cosmological phenomena in connection with concepts of condensed matter Physics via Γeff.http://www.sciencedirect.com/science/article/pii/S2211379724000263Grüneisen parameterDark energyUniverse expansion |
| spellingShingle | Lucas Squillante Gabriel O. Gomes Isys F. Mello Guilherme Nogueira Antonio C. Seridonio Roberto E. Lagos-Monaco Mariano de Souza Exploring the expansion of the universe using the Grüneisen parameter Results in Physics Grüneisen parameter Dark energy Universe expansion |
| title | Exploring the expansion of the universe using the Grüneisen parameter |
| title_full | Exploring the expansion of the universe using the Grüneisen parameter |
| title_fullStr | Exploring the expansion of the universe using the Grüneisen parameter |
| title_full_unstemmed | Exploring the expansion of the universe using the Grüneisen parameter |
| title_short | Exploring the expansion of the universe using the Grüneisen parameter |
| title_sort | exploring the expansion of the universe using the gruneisen parameter |
| topic | Grüneisen parameter Dark energy Universe expansion |
| url | http://www.sciencedirect.com/science/article/pii/S2211379724000263 |
| work_keys_str_mv | AT lucassquillante exploringtheexpansionoftheuniverseusingthegruneisenparameter AT gabrielogomes exploringtheexpansionoftheuniverseusingthegruneisenparameter AT isysfmello exploringtheexpansionoftheuniverseusingthegruneisenparameter AT guilhermenogueira exploringtheexpansionoftheuniverseusingthegruneisenparameter AT antoniocseridonio exploringtheexpansionoftheuniverseusingthegruneisenparameter AT robertoelagosmonaco exploringtheexpansionoftheuniverseusingthegruneisenparameter AT marianodesouza exploringtheexpansionoftheuniverseusingthegruneisenparameter |