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

We investigate time-dependent spherically symmetric solutions of thefour-dimensional Einstein-Maxwell-axion-dilaton system, with the dilatoncoupling that occurs in low-energy effective heterotic string theory. A classof dilaton-electrovacuum radiating solutions with a trivial axion, previouslyfound by G\"uven and Y\"or\"uk, is re-derived in a simpler manner and itscausal structure is clarified. It is shown that such dynamical spacetimesfeaturing apparent horizons do not possess a regular light-like past nullinfinity or future null infinity, depending on whether they are radiating oraccreting. These solutions are then extended in two ways. First we consider aVaidya-like generalisation, which introduces a null dust source. Suchspacetimes are used to test the status of cosmic censorship in the context oflow-energy string theory. We prove that - within this family of solutions -regular black holes cannot evolve into naked singularities by accreting nulldust, unless standard energy conditions are violated. Secondly, we employS-duality to derive new time-dependent dyon solutions with a nontrivial axionturned on. Although they share the same causal structure as theirEinstein-Maxwell-dilaton counterparts, these solutions possess both electricand magnetic charges.

Dynamical black holes in low-energy string theory