Greenberger–Horne–Zeilinger states: Their identifications and robust violations

The [Formula: see text]-qubit Greenberger–Horne–Zeilinger (GHZ) states are the maximally entangled states of [Formula: see text] qubits, which have had many important applications in quantum information processing, such as quantum key distribution and quantum secret sharing. Thus how to distinguish the GHZ states from other quantum states becomes a significant problem. In this work, by presenting a family of the generalized Clauser–Horne–Shimony–Holt (CHSH) inequality, we show that the [Formula: see text]-qubit GHZ states can be indeed identified by the maximal violations of the generalized CHSH inequality under some specific measurement settings. The generalized CHSH inequality is simple and contains only four correlation functions for any [Formula: see text]-qubit system, thus has the merit of facilitating experimental verification. Furthermore, we present a quantum phenomenon of robust violations of the generalized CHSH inequality in which the maximal violation of Bell’s inequality can be robust under some specific noises adding to the [Formula: see text]-qubit GHZ states.

PELANGGARAN PRINSIP KERJA SAMA DALAM PEMBELAJARAN BAHASA INDONESIA DI SMK BATIK 1 SURAKARTA

<em>The purpose of this research is to explain and describe (1) a form of violation of the principle of cooperation in the interaction of learning Indonesian in SMK Batik 1 Surakarta; (2) the purpose of violating the principle of cooperation in learning Indonesian in SMK Batik 1 Surakarta; (3) the function of violating the principle of cooperation in the interaction of learning Indonesian in SMK Batik 1 Surakarta. This research is descriptive qualitative research with main data source that is recording of learning activity of Indonesia in class X Visual Communication Design and XI Marketing. Technique of data retrieval in this research use observation technique and deep interview technique. Technique of taking research subject using purposive sampling technique. The data validity test used is triangulation technique and triangulation theory. Data analysis techniques using interactive analysis techniques. Based on the results of the research, found a speech breaking a maximum of cooperation and speech principles that violate two maxims of cooperation principles, called a single maximal offense and a double maximal offense. Violation of maxim that happened not only done by teacher but also done by student. Maximum violations have 11 violation objectives. Maximum violation of the principle of cooperation done by both students and teachers have their respective functions. The function of language related to maximal violation have 7 functions.</em>

Enhancing violations of Leggett-Garg inequalities in nonequilibrium correlated many-body systems by interactions and decoherence

We identify different schemes to enhance the violation of Leggett-Garg inequalities in open many-body systems. Considering a nonequilibrium archetypical setup of quantum transport, we show that particle interactions control the direction and amplitude of maximal violation, and that in the strongly-interacting and strongly-driven regime bulk dephasing enhances the violation. Through an analytical study of a minimal model we unravel the basic ingredients to explain this decoherence-enhanced quantumness, illustrating that such an effect emerges in a wide variety of systems.

Bell’s inequality, generalized concurrence and entanglement in qubits

It is well known that the maximal violation of the Bell’s inequality for a two-qubit system is related to the entanglement formation in terms of a concurrence. However, a generalization of this relation to an [Formula: see text]-qubit state has not been found. In this paper, we demonstrate some extensions of the relation between the upper bound of the Bell’s violation and a generalized concurrence in several [Formula: see text]-qubit states. In particular, we show the upper bound of the Bell’s violation can be expressed as a function of the generalized concurrence, if a state can be expressed in terms of two variables. We apply the relation to the Wen-Plaquette model and show that the topological entanglement entropy can be extracted from the maximal Bell’s violation.

Evaluating the Maximal Violation of the Original Bell Inequality by Two-Qudit States Exhibiting Perfect Correlations/Anticorrelations

We introduce the general class of symmetric two-qubit states guaranteeing the perfect correlation or anticorrelation of Alice and Bob outcomes whenever some spin observable is measured at both sites. We prove that, for all states from this class, the maximal violation of the original Bell inequality is upper bounded by 3 2 and specify the two-qubit states where this quantum upper bound is attained. The case of two-qutrit states is more complicated. Here, for all two-qutrit states, we obtain the same upper bound 3 2 for violation of the original Bell inequality under Alice and Bob spin measurements, but we have not yet been able to show that this quantum upper bound is the least one. We discuss experimental consequences of our mathematical study.

Nonlocality dynamics for an eight-qubit model in cavity QEDs

We study the nonlocality dynamics for an eight-qubit model in cavity QED, where four atoms are confined in four different cavities, all of them initially prepared in the maximally correlated state of four qubits, which corresponds to the atomic degrees of freedom. The nonlocality evolution for the latter states will show that the corresponding maximal violation of a multipartite Bell inequality will experience revivals at precise times, defining, in analogy with entanglement, nonlocality sudden deaths, as well as nonlocality sudden rebirths. The present contribution paves the way to describe, by employing the nonlocality multipartite correlation measure, collective complex behavior displayed by slightly interacting cavity QED arrays.