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Электронный каталог: Nashed, G. G. L. - Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity
Nashed, G. G. L. - Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity
Статья
Автор: Nashed, G. G. L.
Physics Letters B: Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity
б.г.
ISBN отсутствует
Автор: Nashed, G. G. L.
Physics Letters B: Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity
б.г.
ISBN отсутствует
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Статья
Nashed, G.G.L.
Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity / G.G.L.Nashed, P.V.Tretyakov, A.Eid. – Text : electronic // Physics Letters B. – 2026. – Vol/ 878. – P. 140575. – URL: https://doi.org/10.1016/j.physletb.2026.140575. – Bibliogr.: 123.
We study the cosmological dynamics of the quadratic symmetric teleparallel gravity model 𝑓(𝑄) = 𝑄 + 𝛼𝑄&sup(2) + 𝛽*b, which introduces an 𝐻&sup(4) correction to the Friedmann equation due to 𝑄 ∝ 𝐻&sup(2) . Using the exact algebraic solution for 𝐻(𝑧), we reconstruct the effective dark-energy sector and compare the background evolution with *LCDM using Type Ia supernovae, BAO, and cosmic-chronometer data. At the perturbative level, the model modifies the Poisson equation through a time-dependent effective gravitational coupling 𝐺&sub(e𝑓𝑓) (𝑧) = 𝐺 [ 1 + 2/3 𝐴𝐸&sup(2) (𝑧) ]&sup(−1) , where 𝐴 = 18*a𝐻&sup(2)&sub(0) . For 𝛼 > 0 this produces a weakened gravitational interaction, suppressing the linear growth factor 𝐷(𝑧), the growth rate 𝑓(𝑧), and the RSD observable 𝑓&sub(*s8) (𝑧). In the nonlinear regime, the reduced gravitational strength increases the spherical-collapse threshold and suppresses the halo mass function, leading to a lower predicted value of 𝑆&sub(8) = *s&sub(8) *% *W&sub(𝑚)∕0.3. Thus, the quadratic 𝑓(𝑄) extension can reproduce mild deviations from ΛCDM at the background level while naturally alleviating the 𝑆&sub(8) tension, offering a viable modified-gravity explanation for recent observational hints of dynamical dark energy.
Спец.(статьи,препринты) = С 322.4 - Квантовая гравитация
ОИЯИ = ОИЯИ (JINR)2026
Nashed, G.G.L.
Late-Time Cosmology and Structure Formation in Quadratic f(Q) Gravity / G.G.L.Nashed, P.V.Tretyakov, A.Eid. – Text : electronic // Physics Letters B. – 2026. – Vol/ 878. – P. 140575. – URL: https://doi.org/10.1016/j.physletb.2026.140575. – Bibliogr.: 123.
We study the cosmological dynamics of the quadratic symmetric teleparallel gravity model 𝑓(𝑄) = 𝑄 + 𝛼𝑄&sup(2) + 𝛽*b, which introduces an 𝐻&sup(4) correction to the Friedmann equation due to 𝑄 ∝ 𝐻&sup(2) . Using the exact algebraic solution for 𝐻(𝑧), we reconstruct the effective dark-energy sector and compare the background evolution with *LCDM using Type Ia supernovae, BAO, and cosmic-chronometer data. At the perturbative level, the model modifies the Poisson equation through a time-dependent effective gravitational coupling 𝐺&sub(e𝑓𝑓) (𝑧) = 𝐺 [ 1 + 2/3 𝐴𝐸&sup(2) (𝑧) ]&sup(−1) , where 𝐴 = 18*a𝐻&sup(2)&sub(0) . For 𝛼 > 0 this produces a weakened gravitational interaction, suppressing the linear growth factor 𝐷(𝑧), the growth rate 𝑓(𝑧), and the RSD observable 𝑓&sub(*s8) (𝑧). In the nonlinear regime, the reduced gravitational strength increases the spherical-collapse threshold and suppresses the halo mass function, leading to a lower predicted value of 𝑆&sub(8) = *s&sub(8) *% *W&sub(𝑚)∕0.3. Thus, the quadratic 𝑓(𝑄) extension can reproduce mild deviations from ΛCDM at the background level while naturally alleviating the 𝑆&sub(8) tension, offering a viable modified-gravity explanation for recent observational hints of dynamical dark energy.
Спец.(статьи,препринты) = С 322.4 - Квантовая гравитация
ОИЯИ = ОИЯИ (JINR)2026
