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

Violating Bell's inequalities (BIs) allows one to certify the preparation ofentangled states from minimal assumptions -- in a device-independent manner.Finding BIs tailored to many-body correlations as prepared in present-dayquantum computers and simulators is however a highly challenging endeavour. Inthis work, we focus on BIs violated by very coarse-grain features of thesystem: two-body correlations averaged over all permutations of the parties.For two-outcomes measurements, specific BIs of this form have beentheoretically and experimentally studied in the past, but it is practicallyimpossible to explicitly test all such BIs. Data-driven methods --reconstructing a violated BI from the data themselves -- have therefore beenconsidered. Here, inspired by statistical physics, we develop a noveldata-driven approach specifically tailored to such coarse-grain data. Ourapproach offers two main improvements over the existing literature: 1) it isdirectly designed for any number of outcomes and settings; 2) the obtained BIsare quadratic in the data, offering a fundamental scaling advantage for theprecision required in experiments. This very flexible method, whose complexitydoes not scale with the system size, allows us to systematically improve overall previously-known Bell's inequalities robustly violated by ensembles ofquantum spin-$1/2$; and to discover novel families of Bell's inequalities,tailored to spin-squeezed states and many-body spin singlets of arbitraryspin-$j$ ensembles.

Inferring Nonlinear Many-Body Bell Inequalities From Average Two-Body Correlations: Systematic Approach for Arbitrary Spin-j Ensembles