English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We study second-order cosmological perturbations in scalar-tensor models ofdark energy that satisfy local gravity constraints, including f(R) gravity. Wederive equations for matter fluctuations under a sub-horizon approximation andclarify conditions under which first-order perturbations in the scalar fieldcan be neglected relative to second-order matter and velocity perturbations. Wealso compute the skewness of the matter density distribution and find that thedifference from the LCDM model is only less than a few percent even if thegrowth rate of first-order perturbations is significantly different from thatin the LCDM model. This shows that the skewness provides a model-independenttest for the picture of gravitational instability from Gaussian initialperturbations including scalar-tensor modified gravity models.

Second-order matter density perturbations and skewness in scalar-tensor modified gravity models