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 prove new quantitative limitations on any approximate simultaneous cloningor broadcasting of mixed states. The results are based on information-theoretic(entropic) considerations and generalize the well known no-cloning andno-broadcasting theorems. We also observe and exploit the fact that theuniversal cloning machine on the symmetric subspace of $n$ qudits andsymmetrized partial trace channels are dual to each other. This dualitymanifests itself both in the algebraic sense of adjointness of quantum channelsand in the operational sense that a universal cloning machine can be used as anapproximate recovery channel for a symmetrized partial trace channel and viceversa. The duality extends to give control on the performance of generalizedUQCMs on subspaces more general than the symmetric subspace. This gives a wayto quantify the usefulness of a-priori information in the context of cloning.For example, we can control the performance of an antisymmetric analogue of theUQCM in recovering from the loss of $n-k$ fermionic particles.

Information-theoretic limitations on approximate quantum cloning and broadcasting