Study On The Bipartite Entanglement And Quantum Discord In Even-Even Nuclei Based On The Intermediate Coupling Model

Entanglement is one of the basic characteristics in quantum phenomenon. Quantum entanglement involves reality, locality, and hidden variables and measurement theory and so on, it is important to understand the basic concepts of quantum mechanics. And in recent years it has been in some frontier areas, especially it plays an important role in the study of quantum computation and quantum communication. It is also a essential question in quantum information theory. So to speak, if there is no quantum entanglement phenomenon, it doesn’t matter quantum information.For quantum entanglement, the measure of entanglement is very important, it is a measure of entanglement degree. People put forward all kinds of the entanglement, there are the entanglement of part entropy, entanglement of formation, the entanglement of the relative entropy, purification entanglement, negative value degree, and concurrent degree, etc. Wootters introduced concurrent degree in the calculation of entanglement of formation of the two level two body quantum state (the state space of A system and B system is2d).Entanglement does not express the quantum nature completely, later people extract another physical quantity-quantum discord, It reflects the quantumness of the system from another side. This notion is introduced by Olliver and Zurek, and it is a measure of the discrepancy between two natural yet different quantum analogs of the classical mutual information. It characterizes and quantifies quantumness of correlations in bipartite states from a measurement perspective, and is fundamentally different from the various entanglement measures in the entanglement vs separability paradigm. It can be used as a measure of the quantumness of correlations, and it describes the quantum nonlocal association. To sum up, the entanglement (negative value degree, concurrent degree) and quantum discord are both the embodiment of the quantumness.Atom-cavity, ion trap, two-photon system, and Bose-Einstein condensation body has always been a carrier of the entangled state preparation, and obtained the extensive and in-depth research, but now no one takes the nucleus as the carrier of entangled state preparation. Previously, we have carried on the theoretical exploration and research, investigate the quantumness within the nucleus188O10,188Ne8and5828Ni30. Specifically, we calculate the entanglement degree (negativity and concurrence) and quantum discord between arbitrary two-pair-state on O+state of them, and get some inspiring conclusions. The common characteristic of these nuclei is that they all have a stable core, and there are two valence neutrons outside the core.In this paper, on the basis of the above work, we do further research the quantumness within a class of even-even nucleus with the core excitation. In particular, we chose two typical nuclide,3416S18�'�14860Nd88, as the inspection object. They both have a vibration core excitation, and there are two valence neutrons outside the core.We use the intermediate coupling model to describe such nuclei, the Hamiltonian of the system is composed of single particle shell model Hamiltonian、core vibration Hamiltonian which contains the anharmonic ten core and valence nucleon interaction Hamiltonian and remaining two body interaction Hamiltonian. For3416S18,we take Id3/22s182as the model space of valence neutrons; the remaining two body interaction of two valence neutrons we use comes from the literature. For14860Nd88, the model space of valence neutrons is off for2f1/2lh9/21li13/2the two body interaction of we consider is the delta function potential. We also assume that two neutrons on the same single particle energy level (j1,j2) couple in pairs (J=0). In the calculation, we take the interact strength between the valence neutrons and the core as a adjustable parameter, fit the low excitation experiment spectrum of two species, get the low excitation level of the system and the corresponding state function, and then we calculate and analyze the Von Neumann entropy of3416S18and the measure of entanglement (negativity and concurrence) and quantum discord between arbitrary two-pair-state on0+state of3416S18and14860Nd88, investigate the relationship between the Von Neumann entropy and the state function components, as well as the relationship between the degree of entanglement and quantum discord and the system energy. We also compare and analyze the quantum nature between these two kinds of nuclei3416S18and14860Nd88as well as’188O10,1810Ne8and5828Ni30. In the end. we discuss our work for the next step.