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We extend high-momentum antisymmetrized molecular dynamics (HMAMD) by incorporating the short-range part of the unitary correlation operator method (UCOM) as the variational method of finite nuclei. In this HMAMD+UCOM calculation of light nuclei, HMAMD is mainly in charge of the tensor correlation with up to four-body correlation, while the short-range correlation is further improved by using UCOM. The binding energies of the $^3$H and $^4$He nuclei are calculated with HMAMD+UCOM using the AV8$'$ bare nucleon–nucleon ($NN$) interaction. The different roles of the short-range and tensor correlations from HMAMD and UCOM are analyzed in the numerical results. Compared with previous calculations based on different variational methods, this newly extended HMAMD+UCOM method can almost provide consistent results with ab initio results.

High-momentum components of nuclei are essential for understanding the underlying inter-nucleon correlations in nuclei. We perform the comprehensive analysis for the origin of the high-momentum components of $^4$He in the framework of Tensor-optimized High-momentum Antisymmetrized Molecular Dynamics (TO-HMAMD), which is a completely variational approach as an $ab$ $initio$ theory starting from the bare nucleon-nucleon ($NN$) interaction. The analytical derivations are provided for the nucleon momentum distribution of the Antisymmetrized Momentum Dynamics (AMD) wave functions, with subtraction of center-of-mass motion. The nucleon momentum distribution for $^4$He is calculated by applying a new expansion technique to our $ab$ $initio$ wave function, and agrees with the values extracted from experimental data up to the high-momentum region. Fine-grained analysis is performed for the high-momentum components in $^4$He with respect to different nucleon correlations. Contributions from tensor, central with short-range, and many-body correlations are extracted from the nucleon momentum distributions. The manifestation of tensor correlation around 2 fm$^{-1}$ region is explicitly confirmed by comparing the momentum distributions predicted using different types of $NN$ interactions with and without the tensor force., 7 pages, 6 figures, under review in Phys. Lett. B

We propose a new variational method for describing nuclear matter from nucleon-nucleon interaction. We use the unitary correlation operator method (UCOM) for central correlation to treat the short-range repulsion and further include the two-particle two-hole (2p2h) excitations of nucleon pair involving a large relative momentum, which is called 'high-momentum pair'(HM). We describe nuclear matter in finite size with finite particle number on periodic boundary condition and increase the 2p2h configurations until we get the convergence of the total energy per particle. We demonstrate the validity of this 'UCOM+HM' framework by applying it to the symmetric nuclear and neutron matters with the Argonne V4$^\prime$ potential having short-range repulsion. The nuclear equations of state obtained in UCOM+HM are fairly consistent to those of other calculations such as Brueckner-Hartree-Fock and auxiliary field diffusion Monte Carlo in the overall density region., Comment: 12 pages, 24 figures

By using bare Argonne V4' (AV4'), V6' (AV6'), and V8' (AV8') nucleon-nucleon (NN) interactions respectively, the nuclear equations of state (EOSs) for neutron matter are calculated with the unitary correlation operator and high-momentum pair methods. The neutron matter is described under a finite particle number approach with magic number $N=66$ under a periodic boundary condition. The central short-range correlation coming from the short-range repulsion in the NN interaction is treated by the unitary correlation operator method (UCOM) and the tensor correlation and spin-orbit effects are described by the two-particle two-hole (2p2h) excitations of nucleon pairs, in which the two nucleons with a large relative momentum are regarded as a high-momentum pair (HM). With the 2p2h configurations increasing, the total energy per particle of neutron matter is well converged under this UCOM+HM framework. By comparing the results calculated with AV4', AV6', and AV8' NN interactions, the effects of the short-range correlation, the tensor correlation, and the spin-orbit coupling on the density dependence of the total energy per particle of neutron matter are demonstrated. Moreover, the contribution of each Hamiltonian component to the total energy per particle is discussed. The EOSs of neutron matter calculated within the present UCOM+HM framework agree with the calculations of six different microscopic many-body theories, especially in agreement with the auxiliary field diffusion Monte Carlo calculations., Comment: 13 pages, 6 figures, 3 tables

Within the density-dependent cluster model (DDCM), the decay half-lives of 22 cluster emitters are calculated by using experimental decay energies. Based on our previous study on cluster radioactivity [Phys. Rev. C 90, 064310 (2014)], not only the quadratic symmetry energy ${E}_{2}({\ensuremath{\rho}}_{0})$ and its slope ${L}_{2}({\ensuremath{\rho}}_{0})$ but also the quartic symmetry energy ${E}_{4}({\ensuremath{\rho}}_{0})$ and its slope ${L}_{4}({\ensuremath{\rho}}_{0})$ at the saturation density ${\ensuremath{\rho}}_{0}$ are constrained by considering the neutron skin thicknesses in the daughter nuclei. With the extracted values of ${E}_{2}({\ensuremath{\rho}}_{0})$ and ${L}_{2}({\ensuremath{\rho}}_{0})$, the exponent $\ensuremath{\gamma}$ of the quadratic density-dependent symmetry energy ${E}_{2}(\ensuremath{\rho})={E}_{2}({\ensuremath{\rho}}_{0}){(\ensuremath{\rho}/{\ensuremath{\rho}}_{0})}^{\ensuremath{\gamma}}$ is estimated. Moreover, the symmetry energy coefficient of nuclei ${a}_{\mathrm{sym}}(A)$ and the ratio $\ensuremath{\kappa}$ of the surface symmetry coefficient to the volume symmetry coefficient are extracted as well.

Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus $$^{208}\text {Pb}$$ (Tarbert et al. in Phys Rev Lett 112:242502, 2014), the sensitivity of $$\alpha $$ -decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around $$^{208}\text {Pb}$$ , i.e., isotopes of $$Z=82$$ and isotones of $$N=126$$ . With the two-parameter Fermi (2PF) density distributions and an analytically derived formula, the $$\alpha $$ -decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For $$\alpha $$ decays to the $$Z=82$$ isotopes, the $$\alpha $$ -decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for $$\alpha $$ decays to the $$N=126$$ isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured $$\alpha $$ -decay half-lives.

In this paper, by considering the electrons in different external environments, including neutral atoms, a metal, and an extremely strong magnetic-field environment, the screened α-decay half-lives of the α emitters with proton number Z = 52–105 are systematically calculated. In the external environment, the decay energy and the interaction potential between α particle and daughter nucleus are both changed due to the electron screening effect and their variations are both very important for the electron screening effect. Besides, the electron screening effect is found to be closely related to the decay energy and its proton number.

Background: Recently, the cluster radioactivity of heavy nuclei decaying to $^{208}\mathrm{Pb}$ was successfully used to constrain the density slope of the symmetry energy $L({\ensuremath{\rho}}_{0})$ at saturation density ${\ensuremath{\rho}}_{0}$.Purpose: By using well-measured experimental decay energy and half-life, proton radioactivity is proposed to further constrain $L({\ensuremath{\rho}}_{0})$ in this work.Method: From the Hugenholtz--Van Hove theorem, $L({\ensuremath{\rho}}_{0})$ is found to be directly related to the magnitude of the symmetry potential, which can be extracted from the proton radioactivity within the density-dependent cluster model.Results: By investigating the radioactivity of proton emitters with large isospin asymmetry, the value of the density slope is found to be $L({\ensuremath{\rho}}_{0})=51.8\ifmmode\pm\else\textpm\fi{}7.2$ MeV.