A scheme to solve the Hamiltonian in the interacting boson-fermion model in terms of the SU(3)coupling basis is introduced,through which the effects of an odd particle on shape phase transitions(SPTs)in odd-A nuclei a...A scheme to solve the Hamiltonian in the interacting boson-fermion model in terms of the SU(3)coupling basis is introduced,through which the effects of an odd particle on shape phase transitions(SPTs)in odd-A nuclei are examined by comparing the critical behaviors of some selected quantities in odd-even and even-even systems.The results indicate that the spherical to prolate(U(5)-SU(3))SPT and spherical to γ-soft (U(5)-O(6))SPT may clearly occur in the odd-even system with the SPT signatures revealed by various quantities including the excitation energies,energy ratio,B(E2)ratio,quadrupole moments,and one-particle-transfer spectroscopic intensities.In particular,the results indicate that the spherical to prolate SPT in the odd-even system can even be strengthened by the effects of the odd particle with the large fluctuations of the quadrupole deformations appearing near the critical point.展开更多
A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single pa...A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei.展开更多
The E-Gamma Over Spin （E-GOS） analysis method is applied to the study of the shape phase transition of neutron-rich even-even light nuclei with Z=20-28. Some valuable results are gained through analysing E-GOS curve...The E-Gamma Over Spin （E-GOS） analysis method is applied to the study of the shape phase transition of neutron-rich even-even light nuclei with Z=20-28. Some valuable results are gained through analysing E-GOS curves of Ca, Ti, Cr, Fe and Ni nuclei.展开更多
Some binding energy related quantities serving as effective order parameters have been used to analyze the shape phase transition in the odd Sm nuclei. It is found that the signals of phase transition in the odd Sm nu...Some binding energy related quantities serving as effective order parameters have been used to analyze the shape phase transition in the odd Sm nuclei. It is found that the signals of phase transition in the odd Sm nuclei are greatly enhanced in contrast to the even Sm nuclei. A further analysis shows that the transitional behaviors related to pairing in the Sm nuclei can be well described by the mean field plus pairing interaction model, with a monotonic decrease in the pairing strength G.展开更多
Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicat...Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet. Interestingly, a novel VDS is found in BT nanoplatelets in our simulations. Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot. Furthermore, based on the novel VDS, routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed. In particular, our results show the possibility of designing multi-states devices based on a single VDS. ~ 2017 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics.展开更多
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 fr...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
We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands...We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands are reproduced well. The staggering in ^124-130Xe are almost completely removed and the ？ band agree well with the experiment data, even for the high-spin quasi-3 states. The key quantities of the collective structure evolution, including level energies, the B（E2） transition branching ratios, and the M1 excitations to 11^＋ mixer-symmetry states are analyzed by comparing with the experimental data. The parameters for representation of the Oπν（6） and SUπν^＊（3） features in isotopes are examined. Both experimental data and theoretical results show that the shape phase transition of ^124-134Xe isotopic chain is from the SUπν^＊ （3） （triaxial rotation） to the Uπν（5） （vibration motion） with a considerable constituent of the Oπν（6） symmetry （γ-unstable rotation）, where the shape phase transition rapidly takes place between the neutron number N = 76 and N = 78.展开更多
Pronounced changes of nuclear charge radii provide a stringent benchmark on the theoretical models and play a vital role in recognizing various nuclear phenomena.In this work,the systematic evolutions of nuclear charg...Pronounced changes of nuclear charge radii provide a stringent benchmark on the theoretical models and play a vital role in recognizing various nuclear phenomena.In this work,the systematic evolutions of nuclear charge radii along even Z=84-120 isotopic chains are first investigated by the recently developed new ansatz under the covariant density functional.The calculated results show that the shell closure effects of nuclear charge radii appear remarkably at the neutron numbers N=126 and 184.Interestingly,the arch-like shapes of charge radii between these two strong neutron-closed shells are naturally observed.Across the N=184 shell closure,the abrupt increase in charge radii is still evidently emerged.In addition,the rapid raise of nuclear charge radii from the neutron numbers N=138 to N=144 is disclosed clearly in superheavy regions due to the enhanced shape deformation.展开更多
基金Supported by National Natural Science Foundation of China(11875158)。
文摘A scheme to solve the Hamiltonian in the interacting boson-fermion model in terms of the SU(3)coupling basis is introduced,through which the effects of an odd particle on shape phase transitions(SPTs)in odd-A nuclei are examined by comparing the critical behaviors of some selected quantities in odd-even and even-even systems.The results indicate that the spherical to prolate(U(5)-SU(3))SPT and spherical to γ-soft (U(5)-O(6))SPT may clearly occur in the odd-even system with the SPT signatures revealed by various quantities including the excitation energies,energy ratio,B(E2)ratio,quadrupole moments,and one-particle-transfer spectroscopic intensities.In particular,the results indicate that the spherical to prolate SPT in the odd-even system can even be strengthened by the effects of the odd particle with the large fluctuations of the quadrupole deformations appearing near the critical point.
基金Supported by National Natural Science Foundation of China(11375005)
文摘A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei.
文摘The E-Gamma Over Spin （E-GOS） analysis method is applied to the study of the shape phase transition of neutron-rich even-even light nuclei with Z=20-28. Some valuable results are gained through analysing E-GOS curves of Ca, Ti, Cr, Fe and Ni nuclei.
基金Supported by National Natural Science Foundation of China(11375005,11005056,11175078,11405080)
文摘Some binding energy related quantities serving as effective order parameters have been used to analyze the shape phase transition in the odd Sm nuclei. It is found that the signals of phase transition in the odd Sm nuclei are greatly enhanced in contrast to the even Sm nuclei. A further analysis shows that the transitional behaviors related to pairing in the Sm nuclei can be well described by the mean field plus pairing interaction model, with a monotonic decrease in the pairing strength G.
文摘Shape-induced phase transition of vortex domain structures （VDSs） in BaTiO3 （BT） nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method. Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet. Interestingly, a novel VDS is found in BT nanoplatelets in our simulations. Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot. Furthermore, based on the novel VDS, routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed. In particular, our results show the possibility of designing multi-states devices based on a single VDS. ~ 2017 The Authors. Published by Elsevier Ltd on behalf of The Chinese Society of Theoretical and Applied Mechanics.
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Supported by the National Natural Science Foundation of China under Grant No.11075052the Natural Science Foundation of Zhejiang Province under Grant No.KY6100135
文摘We have investigated the structure evolution of the ^124-134Xe isotopic chain in the framework of the proton-neutron interacting model IBM2. The positive parity spectra of the ground state, quasi-β and quasi-γ bands are reproduced well. The staggering in ^124-130Xe are almost completely removed and the ？ band agree well with the experiment data, even for the high-spin quasi-3 states. The key quantities of the collective structure evolution, including level energies, the B（E2） transition branching ratios, and the M1 excitations to 11^＋ mixer-symmetry states are analyzed by comparing with the experimental data. The parameters for representation of the Oπν（6） and SUπν^＊（3） features in isotopes are examined. Both experimental data and theoretical results show that the shape phase transition of ^124-134Xe isotopic chain is from the SUπν^＊ （3） （triaxial rotation） to the Uπν（5） （vibration motion） with a considerable constituent of the Oπν（6） symmetry （γ-unstable rotation）, where the shape phase transition rapidly takes place between the neutron number N = 76 and N = 78.
基金funded by the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciencessupported partly by the National Natural Science Foundation of China under Grants No.12135004,No.11635003,No.11961141004 and No.12047513+1 种基金the support of the National Natural Science Foundation of China under Grants No.11975096the Fundamental Research Funds for the Central Universities(2020NTST06)。
文摘Pronounced changes of nuclear charge radii provide a stringent benchmark on the theoretical models and play a vital role in recognizing various nuclear phenomena.In this work,the systematic evolutions of nuclear charge radii along even Z=84-120 isotopic chains are first investigated by the recently developed new ansatz under the covariant density functional.The calculated results show that the shell closure effects of nuclear charge radii appear remarkably at the neutron numbers N=126 and 184.Interestingly,the arch-like shapes of charge radii between these two strong neutron-closed shells are naturally observed.Across the N=184 shell closure,the abrupt increase in charge radii is still evidently emerged.In addition,the rapid raise of nuclear charge radii from the neutron numbers N=138 to N=144 is disclosed clearly in superheavy regions due to the enhanced shape deformation.
