Coherence migration in high-dimensional bipartite systems

The conservation law for first-order coherence and mutual correlation of a bipartite qubit state is first proposed by Svozilík et al. [Phys. Rev. Lett. 115, 220501 (2015)], and their theories laid the foundation for the study of coherence migration under unitary transformations. In this paper, we generalize the framework of first-order coherence and mutual correlation to an arbitrary $(m \otimes n)$-dimensional bipartite composite state by introducing an extended Bloch decomposition form of the state. We also generalize two kinds of unitary operators in high-dimensional systems, which can bring about coherence migration and help to obtain the maximum or minimum first-order coherence. Meanwhile, coherence migration in open quantum systems are investigated. We take depolarizing channels as examples and establish that the reduced first-order coherence of the principal system over time is completely transformed into mutual correlation of the $(2 \otimes 4)$-dimensional system-environment bipartite composite state. It is expected that our results may provide a valuable idea or method for controlling the quantum resource such as coherence and quantum correlations.

Cold Particle Dark Matter

Possible dark matter candidates in particle physics span a mass range extending over fifty orders of magnitude. In this review, we consider the range of masses from a few keV to a few hundred TeV, which is relevant for cold particle dark matter. We will consider models where dark matter arises as weakly coupled elementary fields and models where dark matter is a composite state bound by a new strong interaction. Different production mechanisms for dark matter in these models will be described. The landscape of direct and indirect searches for dark matter and some of the resulting constraints on models will be briefly discussed.

Is two-pole’s $$\varLambda (1405)$$ one state or two?

To understand the nature of two poles for the $$\varLambda (1405)$$ Λ ( 1405 ) state, we revisit the interactions of $${\bar{K}}N$$ K ¯ N and $$\pi \Sigma $$ π Σ with their coupled channels, where two-pole structure is found in the second Riemann sheet. We also dynamically generate two poles in the single channel interaction of $${\bar{K}}N$$ K ¯ N and $$\pi \Sigma $$ π Σ , respectively. Moreover, we make a further study of two poles’ properties by evaluating the couplings, the compositeness, the wave functions, and the radii for the interactions of four coupled channels, two coupled channels and the single channel. Our results show that the nature of two poles is unique. The higher-mass pole is a pure $${\bar{K}} N$$ K ¯ N molecule, and the lower-mass one is a composite state of mainly $$\pi \Sigma $$ π Σ with tiny component $${\bar{K}} N$$ K ¯ N . From our results, one can conclude that the $$\varLambda (1405)$$ Λ ( 1405 ) state may be overlapped with two different states of the same quantum numbers.

Local Legitimacy and Tax Policy: Qaids as Part of a Composite State in Colonial Tunisia

The colonial history of Tunisia has long been dictated by colonial sources that made the qaid (an official in charge of fiscal attributions), from the viewpoint of the capital city, a local notable and often a prevaricator. This study proposes to reconsider the relationship between government and regional power in the colonial context by drawing on the recent work of Ottoman studies about provincial elites. The article studies the fiscal reforms of the interwar period in a cereal-growing region of Tunisia, relying on sources in Arabic produced by the qaids, namely the administrative correspondence between local authorities, the prime minister, and colonial controllers. This article describes the role of qaids in the negotiation between national law and local specificities and finally highlights the role of decentralization and a local way of thinking about the state in the 1930s. It contributes to colonial history and the history of taxation by highlighting the territorial fractures in North Africa and the agency of local actors under the protectorate.

Bibliometric Analysis of Composite Resin From 2000-2020

Introduction: To indentify the most effective actors(authors, countries, and journals) about composite resin restorations in the period 2000-2020.Material and Methods: An electronis research was conducted in the Scopus database by selecting the words ‘composite resin’ and ‘restoration and English language, article and review types, dentistry field. Their bibliometric data including publication title, authorship, citation count, citation dentistry, year of publication, country and institution of origin, journal of publication, study design, and keywords were extracted and analyzed.Results and Discussion: To our knowledge, this is the first bibliometric article on composite resin restorations. This study provides information about authors, institutions and countries that contribute to significant improvements in composite resin restorations. From 2000 to 2020, there were 7118 articles published from 99 countries.Articles originate primarily from the USA and Brazil. Results indicate that the USA, Brazil, Germany, Turkey, the United Kingdom, Japan, Swtizerland, Italy, Netherlands and India are the leading countries in composite resin restoration research and account for 51.8% of the total number of publications. The total number of citations are 158.404, corresponding to 22 citations per paper publication. During the time period examined, 776 hot articles and 228 classic articles on composite resin restorations were found.The journal with the most publications is ‘Operative Dentistry’. The publishing houses of the top 10 journals are from 4 countries: USA(6),Netherlands(2),Germany(1),Japan(1). The most cited article within the boundaires of this study is Ferracane’s article titled ‘Resin composite-State of the art’, which was published in Dental Materials in 2011 and received 913 citations.

Asientos as sinews of war in the composite superpower of the 16th century

The full analysis of the text of a contract, asiento, between Philip II of Spain and a Genoese merchant–banker details how in this pre-modern composite state, merchant–bankers acted as agents of the Crown who gathered many scattered sources of income to the Crown and transformed them into large and regular cash flows, mesadas, for the army. Because of the uncertain availability of these sources, the contract provided flexibility to both parties and legal assistance to the banker who reported to accountants for audit and, if necessary, the charge of an interest at about 1 percent per month.

Why Did Russia Not Become a Composite State?

The paper asks how the Russian Empire emerged. In the course of European monarchical rise of the 16–17th centuries, composite monarchies turned into nation states and then empires. Russia never became a composite; very soon after its emergence at the end of the 15th century, it immediately moved to the imperial stage. The answer to why this happened is the key to understanding the Russian Empire’s history. One factor that prevented Russia from building a composite monarchy was the weakness of political actors united under Moscow’s leadership. European composite monarchies emerged when and where the dominant monarchy forcefully broke local laws, fought against local class and political systems. But Moscow’s rivals were too weak, and Russian monarchs did not need to compromise with them. A shared Orthodox faith, common culture, language, and economic structure, as well as the absence of natural borders on the Eastern European plain were other factors that allowed Moscow to ignore the rights of conquered regions. Russia’s background as a part of the Mongol Empire also played a role. By the time Russia faced strong European monarchical competitors, its imperial development path already formed. An important feature of the early Muscovite Empire was the dominance of political practice over ideology. The ideological design of the Empire occurred only in the 18th and 19th century. In the 16th and 17th centuries, the imperial character of Muscovy was formed intuitively and spontaneously; one might call it a neonatal, rudimentary, infant empire.

How Does the Planck Scale Affect Qubits?

Gedanken experiments in quantum gravity motivate generalised uncertainty relations (GURs) implying deviations from the standard quantum statistics close to the Planck scale. These deviations have been extensively investigated for the non-spin part of the wave function, but existing models tacitly assume that spin states remain unaffected by the quantisation of the background in which the quantum matter propagates. Here, we explore a new model of nonlocal geometry in which the Planck-scale smearing of classical points generates GURs for angular momentum. These, in turn, imply an analogous generalisation of the spin uncertainty relations. The new relations correspond to a novel representation of SU(2) that acts nontrivially on both subspaces of the composite state describing matter-geometry interactions. For single particles, each spin matrix has four independent eigenvectors, corresponding to two 2-fold degenerate eigenvalues ±(ℏ+β)/2, where β is a small correction to the effective Planck’s constant. These represent the spin states of a quantum particle immersed in a quantum background geometry and the correction by β emerges as a direct result of the interaction terms. In addition to the canonical qubits states, |0⟩=|↑⟩ and |1⟩=|↓⟩, there exist two new eigenstates in which the spin of the particle becomes entangled with the spin sector of the fluctuating spacetime. We explore ways to empirically distinguish the resulting "geometric" qubits, |0′⟩ and |1′⟩, from their canonical counterparts.