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 study the local distinguishability of general multi-qubit states and showthat local projective measurements and classical communication are as powerfulas the most general local measurements and classical communication. Remarkably,this indicates that the local distinguishability of multi-qubit states can bedecided efficiently. Another useful consequence is that a set of orthogonal$n$-qubit states is locally distinguishable only if the summation of theirorthogonal Schmidt numbers is less than the total dimension $2^n$. When $n=2$such a condition is also sufficient. Employing these results, we show that anyorthonormal basis of a subspace spanned by arbitrary three-qubit orthogonalunextendible product bases (UPB) cannot be exactly distinguishable by localoperations and classical communication. This not only reveals another intrinsicproperty of three-qubit orthogonal UPB, but also provides a class of locallyindistinguishable subspaces with dimension 4. We also explicitly constructlocally indistinguishable subspaces with dimensions 3 and 5, respectively. Inparticular, 3 is the minimal possible dimension of locally indistinguishablesubspaces. Combining with the previous results, we conclude that any positiveinteger between 3 and 7 is the possible dimension of some three-qubit locallyindistinguishable subspace.

Locally Indistinguishable Subspaces Spanned by Three-Qubit Unextendible Product Bases