The \%SU\%(3) limit of the \%sdg\|pf\% interacting boson model is proposed. Applications to the collective states of 236,238 U are discussed. It is shown that the spectra can be well described by the model.
We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first ...We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.展开更多
The method for deriving closed analytic boson realizations of Sp(4) is extended to the search for the boson realizations of shell model algebras Sp(2∧) (∧ is an arbitrary integer).The case of general Sp(2∧) is much...The method for deriving closed analytic boson realizations of Sp(4) is extended to the search for the boson realizations of shell model algebras Sp(2∧) (∧ is an arbitrary integer).The case of general Sp(2∧) is much more complicated than that of Sp(4) because the generators of Sp(2∧) (∧】2) become infinite series It is very difficult to find an exact solution to the boson realization of general Sp (2∧).But if the higher order terms in the generators of Sp(2∧) are neglected,approximate analytic results can he obtained.展开更多
We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and...We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and independent of free parameter(s) are approximately particle number N scale invariant around the critical point of the first order phase transition,similar to that in the second order phase transition.展开更多
A new scheme was recently proposed in which the usual SU（3） quadrupole-quadrupole interaction was replaced by an O（6） cubic interaction in the Interacting Boson Model, and also successfully applied to the descript...A new scheme was recently proposed in which the usual SU（3） quadrupole-quadrupole interaction was replaced by an O（6） cubic interaction in the Interacting Boson Model, and also successfully applied to the description of 152Sm for the N=90 rare earth isotones with X（5） symmetry. By using this new scheme, in the present work, we further explore the properties of another candidate of 150Nd for the N=90 with X（5） symmetry. The low-lying energy levels and E2 transition rates are calculated and compared with the experimental data. The results show that the new scheme can also reasonably describe the experimental low-lying spectrum and the intraband and the interband E2 transitions for 150Nd. However, for the low-lying spectrum, the O（6） cubic interaction seems better in describing the energy levels, especially in higher excited states and γ band, yet the 02＋ level within the β band is lower than the corresponding experimental value and the U（5）-SU（3） scheme seems better to describe the low-lying levels of β band; and for the B（E2） transition, for the intraband transitions within the ground band and some interband transitions between the β band and the ground band, the results from O（6） cubic interaction are better than those from SU（3） quadrupole-quadrupole interaction, yet of which seems better to describe the intraband E2 transitions within β band. The present work is very meaningful in helping us to understand in depth the new characteristics of symmetry by the higher order O（6） cubic interaction.展开更多
I shall present a very brief summary of subjects selected from what Prof. Akito Arima has done in the past years. I will focus on the initial works on the configuration mixing and on the Interacting Boson Model. Since...I shall present a very brief summary of subjects selected from what Prof. Akito Arima has done in the past years. I will focus on the initial works on the configuration mixing and on the Interacting Boson Model. Since there are many literatures on these subjects, I shall concentrate what have been done at the initial or at the pre-history stages. By doing this, we shall see how Prof. Akito Arima started from the scratch.展开更多
The low-lying energy levels and electromagnetic transitions of even-even nuclei ^98Zr, ^100Zr, ^102Zr,^104Zr are studied within the framework of the interacting boson model. The Hamiltonian matrix elements and some of...The low-lying energy levels and electromagnetic transitions of even-even nuclei ^98Zr, ^100Zr, ^102Zr,^104Zr are studied within the framework of the interacting boson model. The Hamiltonian matrix elements and some of their states have been respectively analyzed and determined with respect to the current nuclear experimental data. The B（E2） of electromagnetic transitions have also been calculated and the wave function structures also analyzed. The results show good agreement with the available experimental data. The present study shows that these series of nuclei are in the transition from U（5） to SU（3）, namely from vibration to rotation.展开更多
The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical s...The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the symmetry is given.展开更多
文摘The \%SU\%(3) limit of the \%sdg\|pf\% interacting boson model is proposed. Applications to the collective states of 236,238 U are discussed. It is shown that the spectra can be well described by the model.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10425521, 10935001, 11005056 and 11075052)the Major State Basic Research Development Program (Grant No.G2007CB815000)
文摘We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.
基金Project supported by the National Natural Science Foundation of China
文摘The method for deriving closed analytic boson realizations of Sp(4) is extended to the search for the boson realizations of shell model algebras Sp(2∧) (∧ is an arbitrary integer).The case of general Sp(2∧) is much more complicated than that of Sp(4) because the generators of Sp(2∧) (∧】2) become infinite series It is very difficult to find an exact solution to the boson realization of general Sp (2∧).But if the higher order terms in the generators of Sp(2∧) are neglected,approximate analytic results can he obtained.
基金Supported by the National Natural Science Foundation of China (Grant Nos.10425521 and 10675007)the Major State Basic Research Development Program (Grant No.G2007CB815000)
文摘We study systematically the evolutive behaviors of some energy ratios,E2 transition rate ratios and isomer shift in the nuclear shape phase transitions.We find that the quantities sensitive to the phase transition and independent of free parameter(s) are approximately particle number N scale invariant around the critical point of the first order phase transition,similar to that in the second order phase transition.
基金Supported by Natural Science Foundation of Liaoning Scientific Committee(2013020091)National Natural Science Foundationof China(11375080,10975068)
文摘A new scheme was recently proposed in which the usual SU（3） quadrupole-quadrupole interaction was replaced by an O（6） cubic interaction in the Interacting Boson Model, and also successfully applied to the description of 152Sm for the N=90 rare earth isotones with X（5） symmetry. By using this new scheme, in the present work, we further explore the properties of another candidate of 150Nd for the N=90 with X（5） symmetry. The low-lying energy levels and E2 transition rates are calculated and compared with the experimental data. The results show that the new scheme can also reasonably describe the experimental low-lying spectrum and the intraband and the interband E2 transitions for 150Nd. However, for the low-lying spectrum, the O（6） cubic interaction seems better in describing the energy levels, especially in higher excited states and γ band, yet the 02＋ level within the β band is lower than the corresponding experimental value and the U（5）-SU（3） scheme seems better to describe the low-lying levels of β band; and for the B（E2） transition, for the intraband transitions within the ground band and some interband transitions between the β band and the ground band, the results from O（6） cubic interaction are better than those from SU（3） quadrupole-quadrupole interaction, yet of which seems better to describe the intraband E2 transitions within β band. The present work is very meaningful in helping us to understand in depth the new characteristics of symmetry by the higher order O（6） cubic interaction.
文摘I shall present a very brief summary of subjects selected from what Prof. Akito Arima has done in the past years. I will focus on the initial works on the configuration mixing and on the Interacting Boson Model. Since there are many literatures on these subjects, I shall concentrate what have been done at the initial or at the pre-history stages. By doing this, we shall see how Prof. Akito Arima started from the scratch.
基金Supported by National Natural Science Foundation of China (11165001, 11205079)
文摘The low-lying energy levels and electromagnetic transitions of even-even nuclei ^98Zr, ^100Zr, ^102Zr,^104Zr are studied within the framework of the interacting boson model. The Hamiltonian matrix elements and some of their states have been respectively analyzed and determined with respect to the current nuclear experimental data. The B（E2） of electromagnetic transitions have also been calculated and the wave function structures also analyzed. The results show good agreement with the available experimental data. The present study shows that these series of nuclei are in the transition from U（5） to SU（3）, namely from vibration to rotation.
基金the National Natural Science Foundation of China(Grant Nos.19875001,10075002)the Foundation for University Key Teacher by the Ministry of Education,Chinathe Funds of the Key Laboratory of Heavy Ion Physics at Peking University,Ministry of Education,China.
文摘The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the symmetry is given.
