47 research outputs found
Correlations in self-bound systems of identical fermions
A method for the calculation of translationally invariant wave functions for
systems of identical fermions with arbitrary potential of pair interaction is
developed. It is based on the well-known result that the essential dynamic part
of the Hamiltonian for the system of identical particles is the Reduced
Hamiltonian operator describing relative movement of two particles inside the
system. The eigenfunctions of this operator take into account all correlations
caused by interaction. These eigenfunctions are basic for the construction of
the components (i.e. the functions with a lower degree of antisymmetry) of the
system wave functions. The main problem of this approach appears to be
antisymmetrization of the components. The developed universal algorithm for
antisymmetrization gives a possibility to perform this operation in a simple
way and keep numerical approximations under control.Comment: 20 pages REVTeX, submitted to Lithuanian J. Phy
The general harmonic-oscillator brackets: compact expression, symmetries, sums and Fortran code
We present a very simple expression and a Fortran code for the fast and
precise calculation of three-dimensional harmonic-oscillator transformation
brackets. The complete system of symmetries for the brackets along with
analytical expressions for sums, containing products of two and three brackets,
is given.Comment: 13 pages, accepted for publication in Nuclear Physics
HOTB update: Parallel code for calculation of three- and four-particle harmonic oscillator transformation brackets and their matrices using OpenMP
This is a new version of the HOTB code designed to calculate three and four particle harmonic oscillator (HO) transformation brackets and their matrices. The new version uses the OpenMP parallel communication standard for calculations of harmonic oscillator transformation brackets. A package of fortran code is presented. Calculation time of large matrices, orthogonality conditions and array of coefficients can be significantly reduced using effective parallel code. Other functionalities of the original code (for example calculation of single harmonic oscillator brackets) have not been modified
EVALUATION OF THE DOSE LEVELS IN THE IRRADIATION CHANNELS OF PU-BE NEUTRON SOURCES STORAGE DEVICE BY USING NEUTRON ACTIVATION ANALYSIS AND MCNP6 MODELLING
PuBeneutrons sources of Educational Neutron Laboratory in the Center for Physical Sciences and Technology are used in several activities including neutron activation for educational purposes and laboratory irradiation experiments. In this work we address the dose rate estimation in the irradiation channels of reconstructed PuBe neutron sources storage device in the particular positions dedicated for neutron irradiation experiments using neutron activation analysis (NAA) and MCNP6 modelling.The results on neutron activation of V2O5, MnO2, Al and Na2CO3were analyzed and compared with MCNP6 model prediction results. The conclusions on the actual neutron flux energy distribution and model corrections are drawn. The absolute neutron intensity at dedicated irradiation points as well as neutron and gamma dose rates are obtained
EVALUATION OF THE DOSE LEVELS IN THE IRRADIATION CHANNELS OF PU-BE NEUTRON SOURCES STORAGE DEVICE BY USING NEUTRON ACTIVATION ANALYSIS AND MCNP6 MODELLING
PuBeneutrons sources of Educational Neutron Laboratory in the Center for Physical Sciences and Technology are used in several activities including neutron activation for educational purposes and laboratory irradiation experiments. In this work we address the dose rate estimation in the irradiation channels of reconstructed PuBe neutron sources storage device in the particular positions dedicated for neutron irradiation experiments using neutron activation analysis (NAA) and MCNP6 modelling.The results on neutron activation of V2O5, MnO2, Al and Na2CO3were analyzed and compared with MCNP6 model prediction results. The conclusions on the actual neutron flux energy distribution and model corrections are drawn. The absolute neutron intensity at dedicated irradiation points as well as neutron and gamma dose rates are obtained
Converging upper and lower bounds for ground-state energies of atomic nuclei
By expanding the wave function in terms of the translationally invariant basis of harmonic oscillator functions, we calculate the converging upper (variational) bound for the energy. It is shown that one can construct lower bounds using the reduced density matrix that corresponds to the upper bound. These lower bounds converge to an exact value with the expansion of the basis. We perform the calculations of both bounds with realistic nucleon-nucleon potential for ground states of the triton and the alpha-particle