Macroscopic Coherence in Quantum Mechanics: Quantification and Applications

Leonardo Chiatti, Michele Cini, Maurizio Serva

Hyunseok Jeong, Minsu Kang, Hyukjoon Kwon

We present a review and discussions on characterizations and quantifications of macroscopic quantum states as well as their implementations and applications in optical systems. We compare and criticize different measures proposed to define and quantify macroscopic quantum superpositions and extend such comparisons to several types of optical quantum states actively considered for experimental implementations within recent research topics.

Xiao‐Dong Yu, Otfried Gühne

Coherence is a basic phenomenon in quantum mechanics and considered to be an essential resource in quantum information processing. Although the quantification of coherence has attracted a lot of interest, the lack of efficient methods to measure the coherence in experiments limits the applications. We address this problem by introducing an experiment-friendly method for coherence and spectrum estimation. This method is based on the theory of majorization and can not only be used to prove the presence of coherence, but also result in a rather precise lower bound of the amount of coherence. As an illustration, we show how to characterize the freezing phenomenon of coherence with only two local measurements for any $N$-qubit quantum systems. Our approach also has other applications in quantum information processing, such as the characterization of distillability and entanglement transformations.

Stephan Zanzinger

Partha Ghose

Moïse DANIEL

🇫🇷 Description Ce dépôt présente l’application de la Loi de Quantification Structurelle des Fermetures (LQSF) à la physique quantique. La LQSF formalise la structure générale des systèmes cohérents munis d’un invariant discret et impose trois contraintes fondamentales : localisation des fermetures dans des classes critiques, transitions locales entre classes adjacentes, et globalité des fermetures. Le document développe le formalisme mathématique complet associé à cette loi, puis montre comment ce cadre structurel permet d’unifier plusieurs phénomènes quantiques : intrication, non‑localité, mesures locales, décohérence et émergence des degrés de liberté. Trois extensions naturelles sont également introduites : QS‑O : quantification structurelle des opérateurs, QS‑D : quantification structurelle des dynamiques, QS‑P : quantification structurelle des partitions. L’ensemble constitue un formalisme structurel général pour la physique quantique, indépendant des interprétations usuelles et fondé exclusivement sur la structure discrète des systèmes cohérents. 🇬🇧 Description This deposit presents the application of the Structural Quantification Law of Closures (SQLC) to quantum physics. The SQLC formalizes the general structure of coherent systems equipped with a discrete invariant and imposes three fundamental constraints: localization of closures in critical classes, local transitions between adjacent classes, and globality of closures. The document develops the full mathematical formalism associated with this law, then shows how this structural framework unifies several quantum phenomena: entanglement, non‑locality, local measurements, decoherence, and the emergence of degrees of freedom. Three natural extensions are also introduced: SQ‑O: structural quantification of operators, SQ‑D: structural quantification of dynamics, SQ‑P: structural quantification of partitions. Together, they form a general structural formalism for quantum physics, independent of standard interpretations and based solely on the discrete organization of coherent systems.