Matching Items (1,174)
Description
Monte Carlo methods often used in nuclear physics, such as auxiliary field diffusion Monte Carlo and Green's function Monte Carlo, have typically relied on phenomenological local real-space potentials containing as few derivatives as possible, such as the Argonne-Urbana family of interactions, to make sampling simple and efficient. Basis set methods such as no-core shell model or coupled-cluster techniques typically use softer non-local potentials because of their more rapid convergence with basis set size. These non-local potentials are typically defined in momentum space and are often based on effective field theory. Comparisons of the results of the two types of methods are complicated by the use of different potentials. This thesis discusses progress made in using such non-local potentials in quantum Monte Carlo calculations of light nuclei. In particular, it shows methods for evaluating the real-space, imaginary-time propagators needed to perform quantum Monte Carlo calculations using non-local potentials and universality properties of these propagators, how to formulate a good trial wave function for non-local potentials, and how to perform a "one-step" Green's function Monte Carlo calculation for non-local potentials.
ContributorsLynn, Joel E (Author) / Schmidt, Kevin E (Thesis advisor) / Alarcon, Ricardo (Committee member) / Lebed, Richard (Committee member) / Shovkovy, Igor (Committee member) / Shumway, John (Committee member) / Arizona State University (Publisher)
Created2013
Description
The theory of quantum electrodynamics predicts that beta decay of the neutron into a proton, electron, and anti-neutrino should be accompanied by a continuous spectrum of photons. A recent experiment, RDK I, reported the first detection of radiative decay photons from neutron beta decay with a branching ratio of (3.09 ± 0.32) × 10-3 in the energy range of 15 keV to 340 keV. This was achieved by prompt coincident detection of an electron and photon, in delayed coincidence with a proton. The photons were detected by using a single bar of bismuth germanate scintillating crystal coupled to an avalanche photodiode. This thesis deals with the follow-up experiment, RDK II, to measure the branching ratio at the level of approximately 1% and the energy spectrum at the level of a few percent. The most significant improvement of RDK II is the use of a photon detector with about an order of magnitude greater solid angle coverage than RDK I. In addition, the detectable energy range has been extended down to approximately 250 eV and up to the endpoint energy of 782 keV. This dissertation presents an overview of the apparatus, development of a new data analysis technique for radiative decay, and results for the ratio of electron-proton-photon coincident Repg to electron-proton coincident Rep events.
ContributorsO'Neill, Benjamin (Author) / Alarcon, Ricardo (Thesis advisor) / Drucker, Jeffery (Committee member) / Lebed, Richard (Committee member) / Comfort, Joseph (Committee member) / Chamberlin, Ralph (Committee member) / Arizona State University (Publisher)
Created2012
ContributorsGambhir, Rittika (Performer) / Olarte, Aida (Performer) / Gambhir, Ruchika (Performer) / Chen, Neilson (Performer) / ASU Library. Music Library (Publisher)
Created2018-03-24
Description
Spin-orbit interactions are important in determining nuclear structure. They lead to a shift in the energy levels in the nuclear shell model, which could explain the sequence of magic numbers in nuclei. Also in nucleon-nucleon scattering, the large nucleon polarization observed perpendicular to the plane of scattering needs to be explained by adding the spin-orbit interactions in the potential. Their effects change the equation of state and other properties of nuclear matter. Therefore, the simulation of spin-orbit interactions is necessary in nuclear matter.
The auxiliary field diffusion Monte Carlo is an effective and accurate method for calculating the ground state and low-lying exited states in nuclei and nuclear matter. It has successfully employed the Argonne v6' two-body potential to calculate the equation of state in nuclear matter, and has been applied to light nuclei with reasonable agreement with experimental results. However, the spin-orbit interactions were not included in the previous simulations, because the isospin-dependent spin-orbit potential is difficult in the quantum Monte Carlo method. This work develops a new method using extra auxiliary fields to break up the interactions between nucleons, so that the spin-orbit interaction with isospin can be included in the Hamiltonian, and ground-state energy and other properties can be obtained.
The auxiliary field diffusion Monte Carlo is an effective and accurate method for calculating the ground state and low-lying exited states in nuclei and nuclear matter. It has successfully employed the Argonne v6' two-body potential to calculate the equation of state in nuclear matter, and has been applied to light nuclei with reasonable agreement with experimental results. However, the spin-orbit interactions were not included in the previous simulations, because the isospin-dependent spin-orbit potential is difficult in the quantum Monte Carlo method. This work develops a new method using extra auxiliary fields to break up the interactions between nucleons, so that the spin-orbit interaction with isospin can be included in the Hamiltonian, and ground-state energy and other properties can be obtained.
ContributorsZhang, Jie (Author) / Schmidt, Kevin E (Thesis advisor) / Alarcon, Ricardo (Committee member) / Lebed, Richard (Committee member) / Shumway, John (Committee member) / Arizona State University (Publisher)
Created2014
Description
This study examines the effectiveness of various types of alternative resources in organ building in order to determine whether a change to more sustainable materials would benefit or hinder the overall sound production of the instrument. The qualities of the metals and woods currently used in organ production (e.g. lead, walnut, etc.) have been prized for centuries, so the substitution of different, more sustainable materials must be considered with regards to the sonic alterations, as well as the financial implications, of using alternatives to make the organ more “green.”
Five organ builders were interviewed regarding their views on sustainable materials. In addition, the author consulted the websites of nine national and four international organ builders for information about sustainability, indicating that each organ builder defines the term somewhat differently. Decisions on the woods and metals to be used in building or refurbishing an existing organ are based more on the visual appearance, the sound desired, and the potential for reuse of existing materials. A number of sustainability practices are currently in use by organ builders in the United States and Europe. These include the reuse of transportation boxes, efforts towards recycled metal and wood pipework, and the use of high efficiency lighting.
The investigations into sustainable practice that are presented here document a variety of approaches to sustainability in organ building in the United States, Canada and Europe. This research should assist in the evaluation of further efforts to conserve valuable resources while ensuring the high quality of sound that has characterized the organ throughout its long history.
Five organ builders were interviewed regarding their views on sustainable materials. In addition, the author consulted the websites of nine national and four international organ builders for information about sustainability, indicating that each organ builder defines the term somewhat differently. Decisions on the woods and metals to be used in building or refurbishing an existing organ are based more on the visual appearance, the sound desired, and the potential for reuse of existing materials. A number of sustainability practices are currently in use by organ builders in the United States and Europe. These include the reuse of transportation boxes, efforts towards recycled metal and wood pipework, and the use of high efficiency lighting.
The investigations into sustainable practice that are presented here document a variety of approaches to sustainability in organ building in the United States, Canada and Europe. This research should assist in the evaluation of further efforts to conserve valuable resources while ensuring the high quality of sound that has characterized the organ throughout its long history.
ContributorsGregoire, Jonathan M (Author) / Marshall, Kimberly (Thesis advisor) / Feisst, Sabine (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2014
Description
Following the Restoration of the English monarchy in 1660, musical culture gradually began to thrive under the support of royal patronage and the emerging middle class. The newly crowned Charles II brought with him a love of French music acquired during his time in exile at the court of his cousin, the young Louis XIV. Organ builders, most notably Bernard Smith and Renatus Harris, brought new life to the instrument, drawing from their experience on the Continent to build larger instruments with colorful solo stops, offering more possibilities for performers and composers. Although relatively few notated organ works survive from the Restoration period, composers generated a niche body of organ repertoire exploring compositional genres inspired by late 17th-century English instruments.
The primary organ composers of the Restoration period are Matthew Locke, John Blow, and Henry Purcell; these three musicians began to take advantage of new possibilities in organ composition, particularly the use of two-manuals with a solo register, and their writing displays the strong influence of French and Italian compositional styles. Each adapts Continental forms and techniques for the English organ, drawing from such forms as the French overture and récit pour le basse et dessus, and the Italian toccata and canzona. English organ composers from the Restoration period borrow form, stylistic techniques, ornamentation, and even direct musical quotations, to create a body of repertoire synthesizing both French and Italian styles.
The primary organ composers of the Restoration period are Matthew Locke, John Blow, and Henry Purcell; these three musicians began to take advantage of new possibilities in organ composition, particularly the use of two-manuals with a solo register, and their writing displays the strong influence of French and Italian compositional styles. Each adapts Continental forms and techniques for the English organ, drawing from such forms as the French overture and récit pour le basse et dessus, and the Italian toccata and canzona. English organ composers from the Restoration period borrow form, stylistic techniques, ornamentation, and even direct musical quotations, to create a body of repertoire synthesizing both French and Italian styles.
ContributorsWhitten, Emma (Author) / Marshall, Kimberly (Thesis advisor) / Ryan, Russell (Committee member) / Saucier, Catherine (Committee member) / Arizona State University (Publisher)
Created2014
ContributorsHan, Sarah (Performer) / Kim, Hyewon Rina (Performer) / Chen, Neilson (Performer) / ASU Library. Music Library (Contributor)
Created2018-04-07
Description
Throughout the history of Western art music, political and religious institutions have exerted powerful influence through their patronage and censorship. This is especially relevant to the organ, an elaborate and expensive instrument which has always depended on institutional support. The fascinating story of Polish organ culture, which has existed since the Middle Ages, reflects the dramatic changes in Polish politics throughout the centuries. An understanding of this country's history helps to construct a comprehensive view of how politics influenced the developments in organ building and organ playing. This paper describes the dynamics of the Church, government and art institutions in Poland during the years 1945-2012. A brief summary of the history of Polish organ culture sets the stage for the changes occurring after WWII. The constant struggle between the Church and the communist regime affected music making and organ culture in Poland from 1945-1989. The political détente that occurred after 1989 led to a flowering of new instruments, restorations and performance opportunities for organists. By exploring the relationship between Polish organ culture and prevailing agendas in the 20th century, the author demonstrates how a centuries-old tradition adapted to survive political and economic hardships.
ContributorsKubiaczyk-Adler, Ilona (Author) / Marshall, Kimberly (Thesis advisor) / Micklich, Albie (Committee member) / Rockmaker, Jody (Committee member) / Rogers, Rodney (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2012
Description
The organ is in a continued state of evolution, tonally and mechanically, designed by the builder to meet certain expectations related to the musical aesthetics of the time. Organ building in the United States has been influenced by both European organ building traditions and American innovations. During the early twentieth century, Ernest M. Skinner emerged as one of the greatest organ builders in America. Throughout his life, Skinner's quest was to create an "ideal organ," capable of playing a variety of music. Skinner's vision was rooted in the Romantic Movement and influenced by the dynamic gradations and rich, colorful sonorities of orchestral and operatic music of the era. A number of technological developments were applied to the design of the organ which made the romantic organ possible. The prominent European organ builders of the nineteenth century created organs that defined the romantic-style instrument in their respective countries. By the end of the century, American organ builders were creating their own versions. Skinner traveled to Europe to learn what he could from the foreign builders. Skinner built organs that synthesized European and American elements, along with his own innovations, as continuation of nineteenth-century trends that brought the romantic-symphonic organ to its fullest realization. Additionally, Skinner developed many new organ timbres, including a number of stops that imitate various orchestral instruments. The result of Skinner's creative work is the the American symphonic organ. This paper attempts to illustrate how the tonal designs of organs built by Walcker, Cavaillé-Coll, and Willis influenced the work of Skinner and the American symphonic organ. The work of each builder is discussed with descriptions of their designs. The designs and innovations of Skinner are examined as related to these European builders. A number of organ specifications are provided to supplement the information presented here. Today, American symphonic organs, particularly those built by Skinner, are revered for their warmth and charm and are inspiring the work of present day organ builders who are incorporating elements of this style into their own designs.
ContributorsGerber, James Theodore (Author) / Marshall, Kimberly (Thesis advisor) / Pagano, Caio (Committee member) / Ryan, Russell (Committee member) / Rogers, Rodney (Committee member) / Rockmaker, Jody (Committee member) / Arizona State University (Publisher)
Created2012
Description
Quark matter at sufficiently high density and low temperature is expected to be a color superconductor, and may exist in the interior of neutron stars. The properties of two simplest possible color-superconducting phases, i.e., the color-flavor-locked (CFL) and two-flavor superconducting (2SC) phases, are reviewed. The effect of a magnetic field on the pairing dynamics in two-flavor color-superconducting dense quark matter is investigated. A universal form of the gap equation for an arbitrary magnetic field is derived in the weakly coupled regime of QCD at asymptotically high density, using the framework of Schwinger-Dyson equation in the improved rainbow approximation. The results for the gap in two limiting cases, weak and strong magnetic fields, are obtained and discussed. It is shown that the superconducting gap function in the weak magnetic field limit develops a directional dependence in momentum space. This property of the gap parameter is argued to be a consequence of a long-range interaction in QCD.
ContributorsYu, Lang (Author) / Shovkovy, Igor A. (Thesis advisor) / Lunardini, Cecilia (Committee member) / Schmidt, Kevin (Committee member) / Alarcon, Ricardo (Committee member) / Lebed, Richard (Committee member) / Arizona State University (Publisher)
Created2012