An algebraic diagonalization method is proposed. As two examples, the Hamiltonians of BCS ground stateunder mean-field approximation and XXZ antiferromagnetic model in linear spin-wave frame have been diagonalized byu...An algebraic diagonalization method is proposed. As two examples, the Hamiltonians of BCS ground stateunder mean-field approximation and XXZ antiferromagnetic model in linear spin-wave frame have been diagonalized byusing SU(2), SU(1,1) Lie algebraic method, respectively. Meanwhile, the eigenstates of the above two models are revealedto be SU(2), SU(1,1) coherent states, respectively. The relation between the usual Bogoliubov Valatin transformationand the algebraic method in a special case is also discussed.展开更多
The gap parameter of the standard BCS model is replaced by the order parameter of the modified Ginzburg–Landau theory. Using this new form of the BCS model, the energy, entropy, and heat capacity of ^(93,94,95)Mo nuc...The gap parameter of the standard BCS model is replaced by the order parameter of the modified Ginzburg–Landau theory. Using this new form of the BCS model, the energy, entropy, and heat capacity of ^(93,94,95)Mo nuclei are calculated. The results are compared with the experimental data and standard BCS results. Since the order parameter does not drop to zero at a critical temperature, our results for thermal properties are free of singularities. We have shown that the heat capacity as a function of temperature behaves smoothly and it is highly in agreement with the experimental heat capacity, while heat capacity behaves singularly and discontinuously in the standard BCS model.A smooth peak in the heat capacity is observed which is interpreted as a signature of the transition from the superfluid to the normal phase.展开更多
文摘An algebraic diagonalization method is proposed. As two examples, the Hamiltonians of BCS ground stateunder mean-field approximation and XXZ antiferromagnetic model in linear spin-wave frame have been diagonalized byusing SU(2), SU(1,1) Lie algebraic method, respectively. Meanwhile, the eigenstates of the above two models are revealedto be SU(2), SU(1,1) coherent states, respectively. The relation between the usual Bogoliubov Valatin transformationand the algebraic method in a special case is also discussed.
文摘The gap parameter of the standard BCS model is replaced by the order parameter of the modified Ginzburg–Landau theory. Using this new form of the BCS model, the energy, entropy, and heat capacity of ^(93,94,95)Mo nuclei are calculated. The results are compared with the experimental data and standard BCS results. Since the order parameter does not drop to zero at a critical temperature, our results for thermal properties are free of singularities. We have shown that the heat capacity as a function of temperature behaves smoothly and it is highly in agreement with the experimental heat capacity, while heat capacity behaves singularly and discontinuously in the standard BCS model.A smooth peak in the heat capacity is observed which is interpreted as a signature of the transition from the superfluid to the normal phase.
