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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Pair creation of strings in time-dependent backgrounds is studied from aneffective field theory viewpoint, and some possible cosmological applicationsare discussed. Simple estimates suggest that excited strings may have played asignificant role in preheating, if the string tension as measured infour-dimensional Einstein frame falls a couple of orders of magnitude below thefour-dimensional Planck scale.Comment: 20 pages, latex2e. v2: a reference adde

String production at the level of effective field theory