Nova generacija relativističkih nuklearnih energijskih funkcionala gustoće

master's thesis

• Title (english): The next generation of the relativistic nuclear energy density functionals
• Author: Igor Novak
• Mentor: Tamara Nikšić (mentor)
• Committee member: Tamara Nikšić (predsjednik povjerenstva)
• Committee member: Matko Milin (član povjerenstva)
• Committee member: Ivica Smolić (član povjerenstva)
• Committee member: Mihael Makek (član povjerenstva)
• Committee member: Davor Horvatić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2016-02-23, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovom radu razvijamo novi nuklearni relativistički energijski funkcional gustoće. Relativistički energijski funkcionali gustoće su standardni alat u računima nuklearne strukture i daju sveobuhvatan opis nuklearnih osnovnih stanja i kolektivnih pobuđenja. Predloženi funkcional spada u klasu funkcionala s točkastim vezanjem, kod kojih se lagranžijan formulira preko nukleonskih polja i uključuje samo kontaktna vezanja između struja bilinearnih u Diracovom spinornom polju nukleona. Na temelju ovisnosti mikroskopskih nukleonskih vlastitih energija o gustoći u nuklearnoj materiji konstruirana je fenomenološka pretpostavka kako izgleda ovisnost funkcionala vezanja o gustoći. Na model je potom primjenjena optimizacijska shema koja se sastoji od minimizacije odgovarajuće X^­2 kaznene funkcije koristeći svojstva beskonačne nuklearne materije i konačnih jezgara. Nakon minimizacije provedena je i analiza kovarijanci koja uključuje procjene nepouzdanosti i koeficijenata korelacije. Optimizirani funkcional testiran je na nizu ilustrativnih računa svojstava osnovnih stanja sfernih i deformiranih jezgara kao što su energije vezanja, nabojni radijusi i parametri kvadrupolne deformacije. Dobivena teorijska predviđanja uspoređena su s dostupnim eksperimentalnim podacima i predviđanjima srodnog funkcionala iz klase točkastih vezanja, DD-PC1.

Abstract (english)

In this work we construct a new relativistic nuclear energy density functional. Relativistic energy density functionals are a standard tool for nuclear structure calculations, providing a comprehensive description of nuclear ground states and collective excitations. The proposed functional belongs to a class of point-coupling functionals where a Lagrangian is formulated in terms of nucleon fields and includes only contact couplings between currents bilinear in the Dirac spinor field of the nucleon. Guided by the density dependence of microscopic nucleon self-energies in nuclear matter, a phenomenological ansatz for the density-dependent coupling functionals was constructed. An optimization scheme by minimizing a suitably constructed X^2 penalty function using properties of infinite nuclear matter and finite nuclei was implemented. After the minimization, a covariance analysis that included uncertainty estimates and correlation coefficients was made. The optimized functional was tested in a series of illustrative calculations of ground-state properties of spherical and deformed nuclei, including binding energies, charge radii and quadrupole deformation parameters. Theoretical predictions were compared to the available experimental data, as well as with the predictions of a similar point-coupling functional DD-PC1.

• Keywords: nuklearni relativističi energijski funkcional gustoće
• Keywords (english): relativistic nuclear energy density functional
• Language: croatian
• URN:NBN: urn:nbn:hr:217:688727
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-03-04 17:11:17