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

In recent years, there is a huge interest in the characterization,quantification and manipulation of quantum coherence, a defining nonclassicalfeature of quantum mechanics, by regarding it as a resource in quantuminformation processing. On the other hand, since the early days, there has beena research program using the nonclassical values of some quasiprobabilitydistributions, i.e., those that deviate from the conventional real andnonnegative probability, to indicate the nonclassical aspects of quantumphenomena. Previously, we linked this two nonclassical features of quantummechanics, showing that coherence in a quantum state can indeed bequantitatively characterized by using the total nonreality of the associatedKirkwood-Dirac (KD) quasiprobability. Here, we develop another faithfulquantifier of coherence based on the KD nonclassicality which capturessimultaneously the total nonreality and the total negativity of the real partof the KD quasiprobability. This is motivated by the fact that the real part ofthe KD quasiprobability appears independently of the imaginary part, and itsnegativity has been used to characterize quantumness in different areas ofquantum science and technology. The proposed coherence quantifier, which wecall KD-nonclassicality coherence, gives a lower bound to the $l_1$-normcoherence. It also gives a lower bound to the uncertainty of outcomes ofmeasurement described by a projection-valued measure corresponding to theincoherent orthonormal basis quantified by half of the Tsallis entropy withentropy index $1/2$. For arbitrary pure states, they are shown to be identical.Moreover, KD-nonclassicality coherence is upper bounded by the state purity andmaximized by the maximally coherent states. We then sketch a variational schemefor its direct estimation in laboratory and discuss an application for thecharacterization of static susceptibility.

Characterizing quantum coherence based on the nonclassicality of the Kirkwood-Dirac quasiprobability