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

A new set of boundary conditions for string propagators is proposed in thispaper. The boundary conditions are parametrized by a complex number $\lambda$.Under these new boundary conditions, the left-moving and right-moving modes aretreated unequally. Thus, we called them chiral string theories. If $\lambda =-1$, the spectrum of such theory truncates to a finite number, and therefore itbecomes a different description of supergravity. We found the spectrum ofchiral string theories by requiring that the vertex operators are conformallyinvariant. In addition, we also calculate the amplitudes for arbitrary$\lambda$. The amplitudes are expressed as a product of open string amplitudeswhich are similar to the KLT relation. The unitarity of these theories areinvestigated. However, we found out that except for $\lambda = \pm 1$, allother theories are not unitary; i.e., only the supergravity and ordinarystrings are unitary. Although most of the chiral strings are not physical, theystill serve as a valuable tool in studying the relation between particletheories and string theories.

Chiral string theories as an interpolation between strings and particles