Transformation relation between coherence and entanglement for two-qubit states

Entanglement and coherence are two important resources in quantum information theory. A question naturally arises:Is there some connection between them? We prove that the entanglement of formation and the first-order coherence of twoqubit states satisfy an inequality relation. Two-qubit pure state reaches the upper bound of this inequality. A large number of randomly generated states are used to intuitively verify the complementarity between the entanglement of formation and the first-order coherence. We give the maximum accessible coherence of two-qubit states. Our research results will provide a reliable theoretical basis for conversion of the two quantum resources.

Coherence migration in high-dimensional bipartite systems

The conservation law for first-order coherence and mutual correlation of a bipartite qubit state was firstly proposed by Svozil′?k et al.,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■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,the coherence migration in open quantum systems is 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■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.

Mutual Restriction between Concurrence and Intrinsic Concurrence for Arbitrary Two-Qubit States

Concurrence is viewed as the most commonly approach for quantifying entanglement of two-qubit states,while intrinsic concurrence contains concurrence of four pure states consisting of a special pure state ensemble concerning an arbitrary two-qubit state.Thus,a natural question arises:Whether there is a specified relation between them.We firstly examine the relation between concurrence and intrinsic concurrence for the maximally nonlocal mixed state under a special unitary operation,which is not yet rigorously proved.In order to obtain a general result,we investigate the relation between concurrence and intrinsic concurrence using randomly generated two-qubit states,and derive an inequality relation between them.Finally,we take into account the relation between concurrence and intrinsic concurrence in open systems,and reveal the ratio of the two quantum resources,which is only correlated with the experiencing channels.

Inequality relations for the hierarchy of quantum correlations in two-qubit systems

Entanglement,quantum steering and Bell nonlocality can be used to describe the distinct quantum correlations of quantum systems.Because of their different characteristics and application fields,how to divide them quantitatively and accurately becomes particularly important.Based on the sufficient and necessary criterion for quantum steering of an arbitrary two-qubit T-state,we derive the inequality relations between quantum steering and entanglement as well as between quantum steering and Bell nonlocality for the T-state.Additionally,we have verified those relations experimentally.

Application of Energy Efficiency Optimization Technology in Steel Industry

It’s systematically analyzed that energy efficiency optimization technology has been applied in the field of steel industry. The fundamental principal of energy optimization technology is reasonably matching the quality and price of energy as well as energy-dominated systematic energy efficiency management system. Specific measures of energy optimization have been put forward, which include taking high efficiency utilized technology such as energy saving from the original, the production process and recycling of waste heat and waste energy etc., integrating and configuring energy in an optimized way of high efficiency and excellent quality, fully realizing the function of different energy in order to optimize the utilization sequence of energy, and improving the energy medium system by themselves. Finally it is clearly pointed out that the steel industry should pay more consideration about the great deal of energy system which they have used now and an ideal energy evaluation methodology and standard should be built as soon as possible if they want to take full usage of the real role and function of energy in all aspects.

Complementary relation between quantum entanglement and entropic uncertainty

Quantum entanglement is regarded as one of the core concepts,which is used to describe the nonclassical correlation between subsystems,and entropic uncertainty relation plays a vital role in quantum precision measurement.It is well known that entanglement of formation can be expressed by von Neumann entropy of subsystems for arbitrary pure states.An interesting question is naturally raised:is there any intrinsic correlation between the entropic uncertainty relation and quantum entanglement?Or if the relation can be applied to estimate the entanglement.In this work,we focus on exploring the complementary relation between quantum entanglement and the entropic uncertainty relation.The results show that there exists an inequality relation between both of them for an arbitrary two-qubit system,and specifically the larger uncertainty will induce the weaker entanglement of the probed system,and vice versa.Besides,we use randomly generated states as illustrations to verify our results.Therefore,we claim that our observations might offer and support the validity of using the entropy uncertainty relation to estimate quantum entanglement.