Download or read book Regularization of the Particle particle Interaction in the Nuclear Density Functional Theory written by Piotr Jerzy Borycki and published by . This book was released on 2006 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work we show how to regularize the ultraviolet divergences appearing in the local pairing term of the energy density functional. Our approach, entirely rooted in the framework of the Density Functional Theory, is based on the regularization of local densities and currents and can be applied to various classes of energy density functionals. We demonstrated, that for the particular choice of the pairing term of energy density functional, our procedure gives the same regularization scheme to the one obtained earlier by the means of the pairing gap regularization. We also investigated the non-unitarity of the Bogoliubov transformation due to the energy cutoff in the quasiparticle space. We developed and tested the method of restoring the unitarity of the Bogoliubov transformation. We demonstrated that by applying this method one can perform HFB calculations for significantly lower cutoff energies, without losing accuracy.

Download or read book Relativistic Density Functional For Nuclear Structure written by Jie Meng and published by World Scientific. This book was released on 2016-01-11 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to provide a detailed introduction to the state-of-the-art covariant density functional theory, which follows the Lorentz invariance from the very beginning and is able to describe nuclear many-body quantum systems microscopically and self-consistently. Covariant density functional theory was introduced in nuclear physics in the 1970s and has since been developed and used to describe the diversity of nuclear properties and phenomena with great success.In order to provide an advanced and updated textbook of covariant density functional theory for graduate students and nuclear physics researchers, this book summarizes the enormous amount of material that has accumulated in the field of covariant density functional theory over the last few decades as well as the latest developments in this area. Moreover, the book contains enough details for readers to follow the formalism and theoretical results, and provides exhaustive references to explore the research literature.

Download or read book Nuclear Density Functional Theory written by I. Zh Petkov and published by . This book was released on 1991 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the enormous amount of material accumulated in the field of nuclear density functional theory over the last few decades. The goal of the theory is to provide a complete quantum mechanical description and explanation of nuclear phenomena in terms of the local density distribution as a basic ingredient rather than the many particle wavefunction. This leads to a considerable reduction in the mathematical complexity of nuclear many-body problems and to a great conceptual simplicity and visual clarity in its theoretical treatment. The authors develop the mathematical framework on which the theory is based and consider the associated approaches used to analyze experimental data in a variety of nuclei and nuclear processes with widely differing properties.

Download or read book Density Functional Theory and Phase Shifts written by and published by . This book was released on 2007 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes how phase shifts of the nucleon-nucleon system may be utilized to determine the nuclear Density Functional (DF). The nucleonnucleon interaction, hereafter denoted by N-N interaction, is input to quantum many-body calculations. However, this approach complicates the determination of physical quantities such as the calculation of spectroscopic information and of energy levels. A major advantage in employing the approach via Density Functional Theory (DFT) to this system is that the N-N problem can be considered to be a non-interacting, single-particle system. In order to use DFT one must know the density functional, and this is typically the most difficult aspect of this approach. Usually the DF is parameterized in terms of the density and density gradients, and these parameters are then fit-to-data. In this thesis we consider how the density functional can be related to the phase shifts of the harmonically-trapped twobody system. Research focusing on a specific density functional within the Local Density Approximation (LDA) was found to produce fair results in reproducing the general N-N interaction ground-state energy. In this methodology, the phase shift formula was approximated to first-order via the effective range expansion, which simplified the problem. This provided a fair description of the ground-state energy for the two-body system, with roughly two-percent error between the theoretical model and the exact energies.

Download or read book Interplay Between Single particle and Collective Motion Within Nuclear Density Functional Theory written by Chunli Zhang and published by . This book was released on 2016 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Density Functional Theory written by Eberhard K.U. Gross and published by Springer Science & Business Media. This book was released on 1995-03-31 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first Nato Advanced Studies Institute entirely devoted to density functional theory was held in Portugal in September 1983. The proceedings of this School, publis hed in early 1985, is still used as a standard reference covering the basic development of the theory and applications in atomic, molecular, solid state and nuclear physics. Ho wever, astonishing progress has been achieved in the intervening years: The foundations of the theory have been extended to cover excited states and time dependent problems more fully, density functional theory of classical liquids and superconducting systems has been addressed and extensions to relativistic, that is, field theoretical systems, as well as a more thorough discussion of magnetic field problems have been presented. In addition, new functionals have been devised, for instance under the heading of ge neralised gradient expansions, and the number of applications in the traditional fields has steadily increased, in particular in chemistry. Applications in new fields, as for instance the structure of atomic clusters and the marriage of density functional theory with molecular dynamics and simulated annealing, have provided additional impetus to the field of density functional theory.

Download or read book Beyond mean field Corrections and Effective Interactions in the Nuclear Many body Problem written by Kassem Moghrabi and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mean-field approaches successfully reproduce nuclear bulk properties like masses and radii within the Energy Density Functional (EDF) framework. However, complex correlations are missing in mean-field theories and several observables related to single-particle and collective nuclear properties cannot be predicted accurately. The necessity to provide a precise description of the available data as well as reliable predictions in the exotic regions of the nuclear chart motivates the use of more sophisticated beyond-mean-field models. Correlations and higher-order corrections (beyond the leading mean-field order) are introduced. A crucial aspect in these calculations is the choice of the effective interaction to be used when one goes beyond the leading order (available effective interactions are commonly adjusted at the mean-field level). In the first part, we deal with the equation of state of nuclear matter evaluated up to the second order with the phenomenological Skyrme force. We analyze the ultraviolet divergence that is related to the zero range of the interaction and we introduce Skyrme-type regularized interactions that can be used at second order for matter. Cutoff regularization and dimensional regularization techniques are explored and applied. In the latter case, connections are naturally established between the EDF framework and some techniques employed in Effective Field Theories. In the second part, we check whether the regularized interactions introduced for nuclear matter can be employed also for finite nuclei. As an illustration, this analysis is performed within the particle-vibration model that represents an example of beyond mean-field models where an ultraviolet divergence appears if zero-range forces are used. These first applications suggest several directions to be explored to finally provide regularized interactions that are specially tailored for beyond-mean-field calculations for finite nuclei. Conclusions and perspectives are finally illustrated.

Download or read book Density Functional Theory of 1D Two Particle Systems with Harmonic Interaction written by Marc Andrew Saunders and published by . This book was released on 2004 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pairing and Rotation induced Nuclear Exotica in Covariant Density Functional Theory written by Saja Teeti and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covariant density functional theory (CDFT) is one of the modern theoretical tools for describing the nuclear structure physics of finite nuclei. Its performance is defined by underlying covariant energy density functionals (CEDFs). In this dissertation and within the framework of the CDFT, different physical properties of the ground and the excited states of rotating and non-rotating nuclei have been investigated. A systematic global investigation of pairing properties based on all available experimental data on pairing indicators has been performed for the first time in the framework of covariant density functional theory. It is based on separable pairing interaction of Ref.\ \cite{TMR.09}. The optimization of the scaling factors of this interaction to experimental data clearly reveals its isospin dependence in the neutron subsystem. However, the situation is less certain in the proton subsystem since similar accuracy of the description of pairing indicators can be achieved both with isospin-dependent and mass-dependent scaling factors. The differences in the functional dependencies of scaling factors lead to the uncertainties in the prediction of proton and neutron pairing properties which are especially pronounced at high isospin and could have a significant impact on some physical observables. Although the present investigation is based on the NL5(E) covariant energy density functional (CEDF), its general conclusions are expected to be valid also for other CEDFs built at the Hartree level. It is shown for the first time that rotational bands which are proton unbound at zero or low spins can be transformed into proton bound ones at high spin by collective rotation of nuclear systems. This is due to strong Coriolis interaction, which acts on high-$N$ or strongly mixed M orbitals and drives the highest in energy occupied single-particle states of nucleonic configurations into the negative energy domain. Proton emission from such proton bound rotational states is suppressed by the disappearance of static pairing correlations at high spins of interest. These physical mechanisms lead to a substantial extension of the nuclear landscape beyond the spin zero proton drip line. In addition, a new phenomenon of the formation of giant proton halos in rotating nuclei emerges: it is triggered by the occupation of strongly mixed M intruder orbitals. Possible experimental fingerprints of the transition from particle bound to particle unbound part of rotational bands are discussed and compared for proton and neutron rich nuclei near and beyond respective drip lines.

Download or read book Nuclear Phenomena in Covariant Density Functional Theory written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, covariant density functional theory has been applied to a variety of nuclear phenomena in the ground and excited states of rotating and non-rotating nuclei. It has been applied for the interpretation of excited superdeformed bands in 154Dy using the effective alignmentmethods. The properties of the predicted hyperdeformed nuclei at high spin in the Z = 40-58 region were investigated and the spins at which such configuration become yrast were defined. The moments of inertia, the role of single-particle energies and necking degree of freedom have also been studied. It also predicted that 107Cd is the best nucleus for its observation. The impact of time-odd mean fields (nuclear magnetism NM) in both non-rotating and rotating frame works, on physical observables has been studied. It is shown that nuclear magnetism always provide additional binding to the binding energies of odd-mass nuclei. Time-odd mean fields affect odd-even mass differences. However, the modifications of the strength of pairing correlations required to compensate for their effects are modest. In contrast, time-odd mean fields have a profound effect on the properties of odd-proton nuclei in the vicinity of the proton drip line. Their presence can modify the half-lives of proton emitters and considerably affect the possibilities of their experimental observation. They also have a profound effect on the dynamic and kinematic moments of inertia, particle number, configuration, and rotational frequency dependencies of their impact on the moments of inertia. The effect of NM on the binding energy and moments of inertia weakly depend on the choice of the RMF parametrization. Fission barriers are studied systematically with the allowence for triaxial deformations, in the actinide and superheavy regions. It is shown that covariant density functional theory is able to describe fission barriers, in actinides, on a level of accuracy comparable with nonrelativistic calculations. Triaxiality in the region of the first saddle plays a crucial role in achieving that. However, in the Z = 112 - 120 superheavy nuclei, the inner fission barriers are not affected by triaxiality. General trends of the evolution of inner fission heights are discussed.

Download or read book Nuclear Magnetic Resonance Studies of Interfacial Phenomena written by Vladimir M. Gun'ko and published by CRC Press. This book was released on 2013-04-08 with total page 1043 pages. Available in PDF, EPUB and Kindle. Book excerpt: Properties and applications of high surface area materials depend on interfacial phenomena, including diffusion, sorption, dissolution, solvation, surface reactions, catalysis, and phase transitions. Among the physicochemical methods that give useful information regarding these complex phenomena, nuclear magnetic resonance (NMR) spectroscopy is the most universal, yielding detailed structural data regarding molecules, solids, and interfaces. Nuclear Magnetic Resonance Studies of Interfacial Phenomena summarizes NMR research results collected over the past three decades for a wide range of materials—from nanomaterials and nanocomposites to biomaterials, cells, tissues, and seeds. This book describes the applications of important new NMR spectroscopic methods to a variety of useful materials and compares them with results from other techniques such as adsorption, differential scanning calorimetry, thermally stimulated depolarization current, dielectric relaxation spectroscopy, infrared spectroscopy, optical microscopy, and small-angle and wide-angle x-ray scattering. The text explores the application of NMR spectroscopy to examine interfacial phenomena in objects of increasing complexity, beginning with unmodified and modified silica materials. It then describes properties of various mixed oxides with comparisons to individual oxides and also describes carbon materials such as graphite and carbon nanotubes. Chapters deal with carbon–mineral hybrids and their mosaic surface structures, and interfacial phenomena at the surface of natural and synthetics polymers. They also explore a variety of biosystems, which are much more complex, including biomacromolecules (proteins, DNA, and lipids), cells and tissues, and seeds and herbs. The authors cover trends in interfacial phenomena investigations, and the final chapter describes NMR and other methods used in the book. This text presents a comprehensive description of a large array of hard and soft materials, allowing the analysis of the structure–property relationships and generalities on the interfacial behavior of materials and adsorbates.

Download or read book Application of Density Functional Theory in Nuclear Structure written by Tong Li and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nuclear density functional theory (DFT) is a microscopic self-consistent framework suitable for describing heavy nuclei and performing large-scale studies. In this dissertation I discuss my research works on the development and application of the Skyrme nuclear-DFT framework, covering a broad range of topics, including the nucleon localization in rotating systems, the origin of reflection-asymmetric deformations, the parameter calibration for beta decays, and the development of a new coordinate-space DFT solver.The nucleon localization function (NLF), discussed in the first part, is a useful tool for the visualization of structure information. It has been utilized to characterize clustering and shell structure. How the NLF pattern evolves in rotating systems, how it visualizes internal nuclear structure, and how it is connected with single-particle (s.p.) orbits are discussed in this dissertation. The second part deals with nuclei having reflection-asymmetric shapes, which are important candidates for the search of permanent electric dipole moments. In this dissertation, the origin of pear-like deformation is investigated through both the multipole expansion of the energy density functional and the spectrum of canonical s.p. states. Theoretical predictions of beta-decay rates are discussed next; they are important for r-process simulations that involves nuclei whose experimental beta-decay data are unknown. To provide reliable predictions with quantified uncertainties, the Ï72 optimization is performed to constrain parameters that significantly affect beta-decay transitions in proton-neutron finite-amplitude-method calculations. Besides a well calibrated functional, a reliable and efficient DFT solver is also crucial. The Hartree-Fock-Bogoliubov (HFB) method in the coordinate space is preferred for deformed and weakly bound nuclei, as solvers based on basis expansions often have difficulty correctly describing continuum effects. A new HFB solver based on the canonical-basis HFB formalism in the three-dimensional coordinate space is developed in this dissertation. It is a well parallelized solver and has been carefully benchmarked against other established HFB solvers.

Download or read book Extended Density Functionals in Nuclear Structure Physics written by G. A. Lalazissis and published by Springer Science & Business Media. This book was released on 2004-03-25 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: The experimental and theoretical investigation of nuclei far from the valley of beta-stability is the main subject of modern nuclear structure research. Although the most successful nuclear structure models are purely phenomenological, they nevertheless exploit basic properties of QCD at low energies. This book focuses on the current efforts to bridge the gap between phenomenology and the principles derived from QCD using the extended density functional approach which is based on the successful DFT methods to tackle similarly complex interacting systems in molecular and condensed matter physics. Conceived as a series of pedagogical lectures, this volume addresses researchers in the field as well as postgraduate students and non-specialized scientists from related areas who seek a high-level but accessible introduction to the subject.

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Complex energy Approach to Sum Rules Within Nuclear Density Functional Theory written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The linear response of the nucleus to an external field contains unique information about the effective interaction, correlations governing the behavior of the many-body system, and properties of its excited states. To characterize the response, it is useful to use its energy-weighted moments, or sum rules. By comparing computed sum rules with experimental values, the information content of the response can be utilized in the optimization process of the nuclear Hamiltonian or nuclear energy density functional (EDF). But the additional information comes at a price: compared to the ground state, computation of excited states is more demanding. To establish an efficient framework to compute energy-weighted sum rules of the response that is adaptable to the optimization of the nuclear EDF and large-scale surveys of collective strength, we have developed a new technique within the complex-energy finite-amplitude method (FAM) based on the quasiparticle random- phase approximation. The proposed sum-rule technique based on the complex-energy FAM is a tool of choice when optimizing effective interactions or energy functionals. The method is very efficient and well-adaptable to parallel computing. As a result, the FAM formulation is especially useful when standard theorems based on commutation relations involving the nuclear Hamiltonian and external field cannot be used.

Download or read book Application of Nuclear Density Functional Theory to Exotic Nuclei written by Mengzhi Chen and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear density functional theory (DFT) is the method of choice to study the nuclear properties of medium-mass and heavy nuclei.This dissertation employs the Skryme Hartree-Fock-Bogoliubov (HFB) approach to study nuclear reflection-asymmetric deformations and collective rotation.Nuclear ground states with stable reflection-asymmetric shapes, predicted by theory, have been confirmed experimentally.To explore the microscopic origin of reflection-asymmetric nuclear shapes, we applied the density expansion method to decompose the total HFB energy into different multipolarities. We demonstrated that the reflection-asymmetric deformation is driven by the isoscalar part of the interaction energy.We also confirmed the importance of high-multipolarity fields for stabilizing reflection-asymmetric deformations.The nucleon localization function (NLF) has been successfully applied to characterize nuclear shell structure and collective motion.In our work, we extended the application of NLF to study the nuclear response to fast rotation.By solving the cranked harmonic-oscillator and comparing it with cranked Hartree-Fock results, we defined the simplified localization measure and demonstrated its usefulness as an indicator of nuclear rotation.The above nuclear DFT calculations were performed using existing HFB solvers.However, the current HFB solvers are deficient in the study of exotic nuclei whose properties are strongly affected by the quasiparticle continuum space.For this purpose, we developed a three-dimensional Skyrme-HFB solver HFBFFT in the coordinate-space representation using the canonical basis approach.We implemented the soft energy cutoff and pairing annealing to solve the problem of pairing collapse; a sub-iteration method to improve the convergence, and an algorithm to restore the Hermiticity of differential operators brought by Fourier-transform-based differentiation.The accuracy and performance of HFBFFT were tested by benchmarking it against other HFB codes, both spherical and deformed, for a set of well-bound and weakly-bound nuclei.