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/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

We derive the low-energy expansion of $(Z\alpha) ^{2}$ and $(Z\alpha) ^{4}$terms of the polarization operator in the Coulomb field. Physical applicationssuch as the low-energy Delbr\"{u}ck scattering and "magnetic loop" contributionto the $g$ factor of the bound electron are considered.

$(Z\alpha)^{4}$ order of the polarization operator in Coulomb field at low energy