1,054 research outputs found

    Systematic investigation of the rotational bands in nuclei with Z100Z \approx 100 using a particle-number conserving method based on a cranked shell model

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    The rotational bands in nuclei with Z100Z \approx 100 are investigated systematically by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are taken into account exactly. By fitting the experimental single-particle spectra in these nuclei, a new set of Nilsson parameters (κ\kappa and μ\mu) and deformation parameters (ε2\varepsilon_2 and ε4\varepsilon_4) are proposed. The experimental kinematic moments of inertia for the rotational bands in even-even, odd-AA and odd-odd nuclei, and the bandhead energies of the 1-quasiparticle bands in odd-AA nuclei, are reproduced quite well by the PNC-CSM calculations. By analyzing the ω\omega-dependence of the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions of valence orbitals in each major shell to the angular momentum alignment, the upbending mechanism in this region is understood clearly.Comment: 21 pages, 24 figures, extended version of arXiv: 1101.3607 (Phys. Rev. C83, 011304R); added refs.; added Fig. 4 and discussions; Phys. Rev. C, in pres

    Regularization dependence of pion generalised parton distributions

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    Pion generalised parton distributions are calculated within the framework of the Nambu--Jona-Lasinio model using different regularization schemes, including the proper time regularization scheme, the three dimensional momentum cutoff scheme, the four dimensional momentum cutoff scheme, and the Pauli-Villars regularization scheme. Furthermore, we check the theoretical constraints of pion generalised parton distributions required by the symmetries of quantum chromodynamics in different regularization schemes. The diagrams of pion parton distribution functions are plotted, in addition, we evaluate the Mellin moments of generalised parton distributions, which related to the electromagnetic and gravitational form factors of pion. Pion generalised parton distributions are continuous but not differential at x=±ξx=\pm \,\xi, when considering the effect of D-term, generalised parton distributions become not continuous at x=±ξx=\pm \,\xi in all the four regularization schemes. Generalised parton distributions in impact parameter space are considered, the width distribution of uu quark in the pion and the mean-squared b2πu\langle \mathbf{b}_{\bot}^2\rangle_{\pi}^u are calculated. The light-front transverse-spin distributions are studied, when quark polarized in the light-front-transverse +x+\,x direction, the transverse-spin density is no longer symmetric around (bx=0,by=0)(b_x=0,b_y=0), the peaks shift to (bx=0,by>0)(b_x=0,b_y>0), we compare the average transverse shift by1u\langle b_{\bot}^y\rangle_1^u and by2u\langle b_{\bot}^y\rangle_2^u in different regularization schemes. The light-cone energy radius rE,LCr_{E,LC} and the light-cone charge radius rc,LCr_{c,LC} are also evaluated, we find that in the proper time regularization scheme the values of these quantities are the largest, in the three dimensional momentum cutoff scheme they are the smallest.Comment: 34 pages, 39 figure

    Nuclear superfluidity for antimagnetic rotation in 105^{105}Cd and 106^{106}Cd

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    The effect of nuclear superfluidity on antimagnetic rotation bands in 105^{105}Cd and 106^{106}Cd are investigated by the cranked shell model with the pairing correlations and the blocking effects treated by a particle-number conserving method. The experimental moments of inertia and the reduced B(E2)B(E2) transition values are excellently reproduced. The nuclear superfluidity is essential to reproduce the experimental moments of inertia. The two-shears-like mechanism for the antimagnetic rotation is investigated by examining the shears angle, i.e., the closing of the two proton hole angular momenta, and its sensitive dependence on the nuclear superfluidity is revealed.Comment: 14 pages, 4 figure

    μ-Adipato-bis­[chlorido(2,2′:6′,2′′-terpyridine)­copper(II)] tetra­hydrate

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    In the title compound, [Cu2(C6H8O4)Cl2(C15H11N3)2]·4H2O, the dinuclear copper complex is located on a crystallographic inversion centre. Each Cu atom is in a distorted square-pyramidal coordination environment, with one O atom of an adipate dianion and three N atoms from the 2,2′:6′,2′′-terpyridine ligand occupying the basal plane, and one chlorine in the apical site. In addition, there is weak Cu—O inter­action opposite of the chlorine with a distance of 2.768 (1) Å. The adipate ligand adopts a gauche–anti–gauche conformation. The inter­stitial water mol­ecules form hydrogen-bonded tertramers that are connected to the complexes via O—H⋯O and O—H⋯Cl hydrogen bonds, thus leading to the formation of tightly hydrogen-bonded layers extending perpendicular to the b-axis direction

    Measurement-device-independent QKD with Modified Coherent State

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    The measurement-device-independent quantum key distribution (MDI-QKD) protocol has been proposed for the purpose of removing the detector side channel attacks. Due to the multi-photon events of coherent states sources, real-life implementations of MDI-QKD protocol must employ decoy states to beat the photon-number-splitting attack. Decoy states for MDI-QKD based on the weak coherent states have been studied recently. In this paper, we propose to perform MDI-QKD protocol with modified coherent states (MCS) sources. We simulate the performance of MDI-QKD with the decoy states based on MCS sources. And our simulation indicates that both the secure-key rate and transmission distance can be improved evidently with MCS sources.The physics behind this improvement is that the probability of multi-photon events of the MCS is lower than that of weak coherent states while at the same time the probability of single-photon is higher

    Rotational properties of the superheavy nucleus 256Rf and its neighboring even-even nuclei in particle-number conserving cranked shell model

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    The ground state band was recently observed in the superheavy nucleus 256Rf. We study the rotational properties of 256Rf and its neighboring even-even nuclei by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method in which the blocking effects are taken into account exactly. The kinematic and dynamic moments of inertia of the ground state bands in these nuclei are well reproduced by the theory. The spin of the lowest observed state in 256Rf is determined by comparing the experimental kinematic moments of inertia with the PNC-CSM calculations and agrees with previous spin assignment. The effects of the high order deformation varepsilon6 on the angular momentum alignments and dynamic moments of inertia in these nuclei are discussed.Comment: 7 pages, 6 figures; References and discussion about the cranking Nilsson model added, Fig. 3 modified and Figs. 5 and 6 added; Phys. Rev. C, in pres
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