We solve the equilibrium meanfield equation of state of Ising ferromagnet （obtained from Bragg-Williams theory） by Newton-Raphson method. The number of iterations required to get a convergent solution （within a spe...We solve the equilibrium meanfield equation of state of Ising ferromagnet （obtained from Bragg-Williams theory） by Newton-Raphson method. The number of iterations required to get a convergent solution （within a specified accuracy） of equilibrium magnetisation, at any particular temperature, is observed to diverge in a power law fashion as the temperature approaches the critical value. This is identified as the critical slowing down. The exponent is also estimated. This value of the exponent is compared with that obtained from analytic solution. Besides this, the numerical results are also compared with some experimental results exhibiting satisfactory degree of agreement. It is observed from this study that the information of the invariance of time scale at the critical point is present in the meanfield equilibrium equation of state of Ising ferromagnet.展开更多
We studied the dynamical phase transition in kinetic Ising ferromagnetsdriven by oscillating magnetic field in meanfield approximation. The meanfield differentialequation was solved by sixth order Runge-Kutta-Felberg ...We studied the dynamical phase transition in kinetic Ising ferromagnetsdriven by oscillating magnetic field in meanfield approximation. The meanfield differentialequation was solved by sixth order Runge-Kutta-Felberg method. We calculatedthe transition temperature as a function of amplitude and frequency of oscillatingfield. This was plotted against field amplitude taking frequency as a parameter.As frequency increases the phase boundary is observed to become inflated. The phaseboundary shows an inflection point which separates the nature of the transition. Onthe dynamic phase boundary a tricritical point (TCP) was found, which separates thenature (continuous/discontinuous) of the dynamic transition across the phase boundary.The inflection point is identified as the TCP and hence a simpler method of determiningthe position of TCP was found. TCP was observed to shift towards high fieldfor higher frequency. As frequency decreases the dynamic phase boundary is observeto shrink. In the zero frequency limit this boundary shows a tendency to merge to thetemperature variation of the coercive field.展开更多
As the high-density nuclear equation of state(EOS) is not very well constrained, we suggest that the structural properties from the finite systems can be used to extract a more accurate constraint. By including the st...As the high-density nuclear equation of state(EOS) is not very well constrained, we suggest that the structural properties from the finite systems can be used to extract a more accurate constraint. By including the strangeness degrees of freedom, the hyperon or anti-kaon, the finite systems can then have a rather high-density core which is relevant to the nuclear EOS at high densities directly. It is found that the density dependence of the symmetry energy is sensitive to the properties of multi-K hypernuclei, while the high-density EOS of symmetric matter correlates sensitively to the properties of kaonic nuclei.展开更多
We investigate the properties of the Ce isotopes with neutron number N =60 - 90 and the properties of the heavy nuclei near 242Am within the framework of deformed relativistic mean-field （RMF） theory. A systematic c...We investigate the properties of the Ce isotopes with neutron number N =60 - 90 and the properties of the heavy nuclei near 242Am within the framework of deformed relativistic mean-field （RMF） theory. A systematic comparison between theoretical results and experimental data is made. The calculated binding energies, two-neutron separation energies, and two-proton separation energies are in good agreement with experimental ones. The variation trend of experimental quadrupole deformation parameters on the Ce isotopes can be approximately reproduced by the RMF model. It is found that there exists an abnormally large deformation in the ground state of proton-rich Ce isotopes. This phenomenon can be the general behavior of proton-rich nuclei on the neighboring isotopic chains such as Nd and Sin isotopes. For the heavy nuclei near ^242 Am the properties of the ground state and superdeformed isomeric state can be approximately reproduced by the RMF model. The mechanism of the appearance of anomalously large deformation or superdeformation is analyzed and its influence on nuclear properties is discussed. Parther experiments to study the anomalously large deformation in some proton-rich nuclei are suggested.展开更多
A mean-field approximation (MFA) is used to treat the crystal-field and transverse-field effects of the spin-1 Ising modle in the presence of longitudinal field. In spite of its simplicity, this scheme still gives the...A mean-field approximation (MFA) is used to treat the crystal-field and transverse-field effects of the spin-1 Ising modle in the presence of longitudinal field. In spite of its simplicity, this scheme still gives the satisfied results.展开更多
This paper discusses mean-field backward stochastic differentiM equations （mean-field BS- DEs） with jumps and a new type of controlled mean-field BSDEs with jumps, namely mean-field BSDEs with jumps strongly coupled...This paper discusses mean-field backward stochastic differentiM equations （mean-field BS- DEs） with jumps and a new type of controlled mean-field BSDEs with jumps, namely mean-field BSDEs with jumps strongly coupled with the value function of the associated control problem. The authors first prove the existence and the uniqueness as well as a comparison theorem for the above two types of BSDEs. For this the authors use an approximation method. Then, with the help of the notion of stochastic backward semigroups introduced by Peng in 1997, the authors get the dynamic programming principle （DPP） for the value functions. Furthermore, the authors prove that the value function is a viscosity solution of the associated nonlocal Hamilton-Jacobi-Bellman （HJB） integro-partial differential equation, which is unique in an adequate space of continuous functions introduced by Barles, et al. in 1997.展开更多
文摘We solve the equilibrium meanfield equation of state of Ising ferromagnet （obtained from Bragg-Williams theory） by Newton-Raphson method. The number of iterations required to get a convergent solution （within a specified accuracy） of equilibrium magnetisation, at any particular temperature, is observed to diverge in a power law fashion as the temperature approaches the critical value. This is identified as the critical slowing down. The exponent is also estimated. This value of the exponent is compared with that obtained from analytic solution. Besides this, the numerical results are also compared with some experimental results exhibiting satisfactory degree of agreement. It is observed from this study that the information of the invariance of time scale at the critical point is present in the meanfield equilibrium equation of state of Ising ferromagnet.
文摘We studied the dynamical phase transition in kinetic Ising ferromagnetsdriven by oscillating magnetic field in meanfield approximation. The meanfield differentialequation was solved by sixth order Runge-Kutta-Felberg method. We calculatedthe transition temperature as a function of amplitude and frequency of oscillatingfield. This was plotted against field amplitude taking frequency as a parameter.As frequency increases the phase boundary is observed to become inflated. The phaseboundary shows an inflection point which separates the nature of the transition. Onthe dynamic phase boundary a tricritical point (TCP) was found, which separates thenature (continuous/discontinuous) of the dynamic transition across the phase boundary.The inflection point is identified as the TCP and hence a simpler method of determiningthe position of TCP was found. TCP was observed to shift towards high fieldfor higher frequency. As frequency decreases the dynamic phase boundary is observeto shrink. In the zero frequency limit this boundary shows a tendency to merge to thetemperature variation of the coercive field.
基金supported by the National Natural Science Foundation of China(Nos.11275048,11775049)the China Jiangsu Provincial Natural Science Foundation(No.BK20131286)
文摘As the high-density nuclear equation of state(EOS) is not very well constrained, we suggest that the structural properties from the finite systems can be used to extract a more accurate constraint. By including the strangeness degrees of freedom, the hyperon or anti-kaon, the finite systems can then have a rather high-density core which is relevant to the nuclear EOS at high densities directly. It is found that the density dependence of the symmetry energy is sensitive to the properties of multi-K hypernuclei, while the high-density EOS of symmetric matter correlates sensitively to the properties of kaonic nuclei.
基金国家自然科学基金，国家重点基础研究发展计划(973计划)，中国科学院知识创新工程项目，the Research Fund for the Doctoral Program of Higher Education of China
文摘We investigate the properties of the Ce isotopes with neutron number N =60 - 90 and the properties of the heavy nuclei near 242Am within the framework of deformed relativistic mean-field （RMF） theory. A systematic comparison between theoretical results and experimental data is made. The calculated binding energies, two-neutron separation energies, and two-proton separation energies are in good agreement with experimental ones. The variation trend of experimental quadrupole deformation parameters on the Ce isotopes can be approximately reproduced by the RMF model. It is found that there exists an abnormally large deformation in the ground state of proton-rich Ce isotopes. This phenomenon can be the general behavior of proton-rich nuclei on the neighboring isotopic chains such as Nd and Sin isotopes. For the heavy nuclei near ^242 Am the properties of the ground state and superdeformed isomeric state can be approximately reproduced by the RMF model. The mechanism of the appearance of anomalously large deformation or superdeformation is analyzed and its influence on nuclear properties is discussed. Parther experiments to study the anomalously large deformation in some proton-rich nuclei are suggested.
文摘A mean-field approximation (MFA) is used to treat the crystal-field and transverse-field effects of the spin-1 Ising modle in the presence of longitudinal field. In spite of its simplicity, this scheme still gives the satisfied results.
基金supported by the National Natural Science Foundation of China under Grant Nos.11171187,11222110Shandong Province under Grant No.JQ201202+1 种基金Program for New Century Excellent Talents in University under Grant No.NCET-12-0331111 Project under Grant No.B12023
文摘This paper discusses mean-field backward stochastic differentiM equations （mean-field BS- DEs） with jumps and a new type of controlled mean-field BSDEs with jumps, namely mean-field BSDEs with jumps strongly coupled with the value function of the associated control problem. The authors first prove the existence and the uniqueness as well as a comparison theorem for the above two types of BSDEs. For this the authors use an approximation method. Then, with the help of the notion of stochastic backward semigroups introduced by Peng in 1997, the authors get the dynamic programming principle （DPP） for the value functions. Furthermore, the authors prove that the value function is a viscosity solution of the associated nonlocal Hamilton-Jacobi-Bellman （HJB） integro-partial differential equation, which is unique in an adequate space of continuous functions introduced by Barles, et al. in 1997.
