Three-body model for an isoscalar spin-triplet neutron-proton pair in 102Sb^{102}{\rm Sb}

We discuss the isoscalar $T=0, S=1$ pairing correlation in the low-lying states of $^{102}{\rm Sb}={}^{100}{\rm Sn}+p+n$ nucleus. To this end, we employ ${\rm core}+p+n$ three-body model with the model space constructed by self-consistent mean-field calculations. The model is developed with both non-relativistic and relativistic effective interactions, the latter of which are found to be more realistic for the present case due to the pseudo-spin symmetry. It turns out that the $(L,S,T)=(0,1,0)$ pairing scheme is strongly hindered in $^{102}$Sb with the relativistic model because of the near degeneracy of the $g_{7/2}$ and $d_{5/2}$ orbitals in the valence space. This pair-breaking effect is clearly seen in the charge-exchange Gamow-Teller-type transitions rather than in the binding energies of $T=0$ and $T=1$ states.Comment: 12 pages, 10 figures. The title has been changed. Accepted for publication in Phys. Rev.

Collectivity in small and large amplitude microscopic mean-field dynamic

The time-dependent energy density functional with pairing allows to describe a large variety of phenomena from small to large amplitude collective motion. Here, we briefly summarize the recent progresses made in the field using the TD-BCS approach. A focus is made on the mapping of the microscopic mean-field dynamic to the macroscopic dynamic in collective space. A method is developed to extract the collective mass parameter from TD-EDF. Illustration is made on the fission of $^{258}$Fm. The collective mass and collective momentum associated to quadrupole deformation including non-adiabatic effects is estimated along the TD-EDF path. With these information, the onset of dissipation during fission is discussed.Comment: Proceeding of the XXII Nuclear Physics Workshop, Kazimierz, 2015, Polan

3次元座標表示の相対論的密度汎関数計算に対する新しい方法

Tohoku University萩野浩一課

Collective aspects deduced from time-dependent microscopic mean-field with pairing: application to the fission process

Given a set of collective variables, a method is proposed to obtain the associated conjugated collective momenta and masses starting from a microscopic time-dependent mean-field theory. The construction of pairs of conjugated variables is the first step to bridge microscopic and macroscopic approaches. The method is versatile and can be applied to study a large class of nuclear processes. An illustration is given here with the fission of $^{258}$Fm. Using the quadrupole moment and eventually higher-order multipole moments, the associated collective masses are estimated along the microscopic mean-field evolution. When more than one collective variable are considered, it is shown that the off-diagonal matrix elements of the inertia play a crucial role. Using the information on the quadrupole moment and associated momentum, the collective evolution is studied. It is shown that dynamical effects beyond the adiabatic limit are important. Nuclei formed after fission tend to stick together for longer time leading to a dynamical scission point at larger distance between nuclei compared to the one anticipated from the adiabatic energy landscape. The effective nucleus-nucleus potential felt by the emitted nuclei is finally extracted.Comment: 12 pages, 9 figure

A simplified BBGKY hierarchy for correlated fermionic systems from a Stochastic Mean-Field approach

The stochastic mean-field (SMF) approach allows to treat correlations beyond mean-field using a set of independent mean-field trajectories with appropriate choice of fluctuating initial conditions. We show here, that this approach is equivalent to a simplified version of the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy between one-, two-, ..., N-body degrees of freedom. In this simplified version, one-body degrees of freedom are coupled to fluctuations to all orders while retaining only specific terms of the general BBGKY hierarchy. The use of the simplified BBGKY is illustrated with the Lipkin-Meshkov-Glick (LMG) model. We show that a truncated version of this hierarchy can be useful, as an alternative to the SMF, especially in the weak coupling regime to get physical insight in the effect beyond mean-field. In particular, it leads to approximate analytical expressions for the quantum fluctuations both in the weak and strong coupling regime. In the strong coupling regime, it can only be used for short time evolution. In that case, it gives information on the evolution time-scale close to a saddle point associated to a quantum phase-transition. For long time evolution and strong coupling, we observed that the simplified BBGKY hierarchy cannot be truncated and only the full SMF with initial sampling leads to reasonable results.Comment: 10 pages, 4 figure

Microscopic description of large amplitude collective motion in the nuclear astrophysics context

In the last 10 years, we have observed an important increase of interest in the application of time-dependent energy density functional theory (TD-EDF). This approach allows to treat nuclear structure and nuclear reaction from small to large amplitude dynamics in a unified framework. The possibility to perform unrestricted three-dimensional simulations using state of the art effective interactions has opened new perspectives. In the present article, an overview of applications where the predictive power of TD-EDF has been benchmarked is given. A special emphasize is made on processes that are of astrophysical interest. Illustrations discussed here include giant resonances, fission, binary and ternary collisions leading to fusion, transfer and deep inelastic processes.Comment: To appear in a special issue of IJMPE on "Collectivity in Nuclei, Neutrinos, and Neutron Stars

Vapochromic films of pi-conjugated polymers based on coordination and desorption at hypervalent tin(iv)-fused azobenzene compounds

We report the synthesis and vapochromic behaviors of film materials consisting of hypervalent tin-containing π-conjugated polymers. We prepared copolymers with brominated tin-fused azobenzenes and modified fluorene having tetraethylene glycol as a side chain. The synthesized polymers showed good film-formability and high affinity with coordinating solvent molecules such as dimethyl sulfoxide (DMSO). In particular, we discovered distinct color changes from blue to purple when exposed to DMSO vapor. It was revealed that color changes should originate from reversible alteration of the coordination-number between five and six of hypervalent tin(IV) in the azobenzene compounds involved in the main-chain conjugation. Moreover, we also observed that binding constants between tin and coordinating solvents could be influenced by two substitutions on the tin atom and subsequently modulated responsivity of vapochromism in films by altering the type of substituent. Furthermore, the color-change behaviors can be estimated by quantum calculations with density functional theory. We demonstrate not only that hypervalent tin can work as a switching unit for modulating the electronic structures of π-conjugated polymers triggered by solvent coordination but also that vapochromic behaviors in films can be predicted by estimating the affinity between hypervalent tin and solvent molecules with theoretical calculations