We applied the ATDHFB approach for study of properties of collective quadrupole states in several transactinide nuclei: 238 U , 240 Pu , 242 Pu , 246 Cm , 248 Cm , 250 Cf and 252 Cf . Calculated energies and B(E2) transition probabilities are in a reasonable agreement with experimental data. We present also results concerning superdeformed collective states in the second minimum of potential energy of the 240 Pu nucleus.
We present an attempt to describe low lying quadrupole collective excitations within the frame of the RMF theory. Single particle wavefunctions obtained from the RMF are used to calculate mass parameters in the cranking approximation of the ATDHFB. The general Bohr hamiltonian with the calculated mass parameters yields collective energies and wavefunctions. Theoretical results are compared with the experimental data in the case of the γ soft 110 Ru and 126 Ba nuclei.
The stability and collective excitations of binary Bose–Einstein condensates with cubic and quintic nonlinearities in variable anharmonic optical lattices are investigated. By using the variational approach, the influences of the quintic nonlinearities and the shape of the external potential on the stability are discussed in details. It is found that the quintic intraspecies and interspecies interatomic interactions profoundly affect the stability criterion and collective excitations of the system. The shape dependent potential form that characterizes the optical lattice deeply alters the stability regions. Direct numerical simulations of the mean-field coupled Gross–Pitaevskii equation describing the system agree well with the analytical predictions.
Hartree–Fock theory has been justified as a mean-field approximation for fermionic systems. However, it suffers from some defects in predicting physical properties, making necessary a theory of quantum correlations. Recently, bosonization of many-body correlations has been rigorously justified as an upper bound on the correlation energy at high density with weak interactions. We review the bosonic approximation, deriving an effective Hamiltonian. We then show that for systems with Coulomb interaction this effective theory predicts collective excitations (plasmons) in accordance with the random phase approximation of Bohm and Pines, and with experimental observation.
Inhomogeneous mean-field approach to collective excitations near the superfluid-Mott glass transition
