Thermal activation, long-range ordering, and topological frustration of artificial spin ice

Frustrated systems, typically characterized by competing interactions that cannot all be simultaneously satisfied, are ubiquitous in nature and display many rich phenomena and novel physics. Artificial spin ices (ASIs), arrays of lithographically patterned Ising-like single-domain magnetic nanostructures, are highly tunable systems that have proven to be a novel method for studying the effects of frustration and associated properties. The strength and nature of the frustrated interactions between individual magnets are readily tuned by design and the exact microstate of the system can be determined by a variety of characterization techniques. Recently, thermal activation of ASI systems has been demonstrated, introducing the spontaneous reversal of individual magnets and allowing for new explorations of novel phase transitions and phenomena using these systems. In this work, we introduce a new, robust material with favorable magnetic properties for studying thermally active ASI and use it to investigate a variety of ASI geometries. We reproduce previously reported perfect ground-state ordering in the square geometry and present studies of the kagome lattice showing the highest yet degree of ordering observed in this fully frustrated system. We consider theoretical predictions of long-range order in ASI and use both our experimental studies and kinetic Monte Carlo simulations to evaluate these predictions. Next, we introduce controlled topological defects into our square ASI samples and observe a new, extended frustration effect of the system. When we introduce a dislocation into the lattice, we still see large domains of ground-state order, but, in every sample, a domain wall containing higher energy spin arrangements originates from the dislocation, resolving a discontinuity in the ground-state order parameter. Locally, the magnets are unfrustrated, but frustration of the lattice persists due to its topology. We demonstrate the first direct imaging of spin configurations resulting from topological frustration in any system and make predictions on how dislocations could affect properties in numerous materials systems.

Solo and Chamber Music of Pulitzer Prize-Winning Composers

The Pulitzer Prize in Music, established in 1943, is one of America's most prestigious awards. It has been awarded to fifty-three composers for a "distinguished musical composition of significant dimension by an American that has had its first performance in the United States during the year." Composers who have won the Pulitzer Prize are considered to be at the pinnacle of their creativity and have provided the musical world with classical music compositions worthy of future notice. By tracing the history of Pulitzer Prize-winning composers and their compositions, researchers and musicians enhance their understanding of the historical evolution of American music, and its impact on American culture. Although the clarinet music of some of these composers is rarely performed today, their names will be forever linked to the Pulitzer, and because of that, their compositions will enjoy a certain sense of immortality. Of the fifty-four composers who have won the award, forty-seven have written for the clarinet in a solo or chamber music setting (five or less instruments). Just as each Pulitzer Prize-winning composition is a snapshot of the state of American music at that time, these works trace the history of American clarinet musical development, and therefore, they are valuable additions to the clarinet repertoire and worthy of performance. This dissertation project consists of two recitals featuring the solo and chamber clarinet music of sixteen Pulitzer Prize-winning composers, extended program notes containing information on each composer's life, their music, the Pulitzer Prize-winning composition and the recital selection, and a complete list of all Pulitzer Prize-winning composers and their solo and chamber clarinet music. Featured Composers Dominick Argento, To Be Sung Upon the Water Leslie Bassett, Soliloquies William Bolcom, Little Suite of Four Dances Aaron Copland, As it Fell Upon a Day John Corigliano, Soliloquy Norman Dello Joio, Concertante Morton Gould, Benny's Gig Charles Ives, Largo Douglas Moore, Quintet for Clarinet and Strings George Perle, Three Sonatas Quincy Porter, Quintet for Clarinet and Strings Mel Powell, Clarinade Shulamit Ran, Private Game Joseph Schwantner, Entropy Leo Sowerby, Sonata Ernst Toch, Adagio elegiaco

Doubt, for narrator and orchestra

Doubt is a single-movement composition of roughly twelve minutes for narrator and orchestra (woodwinds, horns, and trumpets in pairs, timpani, percussion, strings). The piece explores the controversial issue of capital punishment. The text was compiled from resources found on the websites of Death Penalty Information Center (http://www.deathpenaltyinfo.org) and Anti-Death Penalty Information (http://www.antideathpenalty.org), as well as excerpts from the Bible. Doubt was conceived of as a dramatic work in which a narrator recites factual information in a direct and unemotional manner and the orchestra provides a response to the mixed emotions elicited by the text. The list of dates and case summaries presented in the middle section of the piece seemed most powerful and effective when recited in a natural speaking voice, which is why I chose not to set the text as song. Also, I chose the orchestral medium rather than a chamber setting because the nature of the topic demanded a larger range of colors and combinations, as well as a louder, fuller sound. Much of the music was composed while deciding which texts to include. Thus the music influenced the choice of text as much as the text suggested the musical setting. The four formal divisions of the piece are delineated primarily by the text. The first section is an orchestral introduction representing various emotional perspectives suggested by the texts. The narrator begins the second section with a Biblical verse over sparse orchestration. The third and main section of the piece begins with a new melody in the low strings that is closely related to the harmonic organization of the piece. The narrator lists dates of convictions, executions, exonerations and facts related to doubtful cases. The third section and the narration conclude with another brief passage from the Bible. The fourth section is a dramatic orchestral coda, bringing back the opening harmonies of juxtaposed perfect fifths. The final chord is full of tension and discord, reflecting the oppositions inherent in the topic of capital punishment: life vs. death, sympathy vs. reproach, pain vs. hope, but above all, doubt about guilt vs. innocence.

Lament for String Quartet

This piece explores the changing nature of emotion focusing especially on the feeling of sorrow. The opening and ending parts of the first movement represent the overall motive of sorrow. The first movement opens with an augmented chord G-C#-F-B and from this chord the first violin expands upwards while the cello moves downwards towards the C chord (p.2). As the melody alternates between each part, there is a subtle change in harmony which creates tension and release and changes the sound color. In addition, ornamentation in each part reinforces the movement towards the C chord. This progression represents the inner emotion of lament. Sostenuto e largamente section (p.2) uses heterophony in order to express a feeling of chaos. Section Scherzando (p.4) uses the interval relationship M7 and m2, and is a respite from the overwhelming feeling of sorrow. The ending of the first movement (p.12) returns to create a second tension by every instrument ascending slowly, and the viola produces a distinctive melody derived from the previous chaotic section that ends on an Ab. The second movement contrasts with the first movement in order to express a concealed, not explicit, sorrow, and differs in both tempo and texture. The tempo is a waltz that is faster than the first movement. This produces a light, playful figure and a simple melody without much ornamentation. Imitation and canonic structure emphasize the individuality of the strings. The third movement merges material from the first movement rhythmic figure and the second movement pizzicato (p.17). It shows timbral change through con sordino, pizzicato arpeggio, and sul ponticello to display string techniques. An Allegro section (p.19) especially contrasts with Misterioso in rhythm and dynamics. In the Grazioso (p.22), random beats are accentuated by pizzicato arpeggio to de-emphasize the meter. Finally, there is a return to the ending figure of the first movement with con sordino (p.23) and sul ponticello in viola that articulates the internal tension and the timbral change to return to a voice of sorrow.

The Oud Across Arabic Culture

This study is a compilation and compendium of information on the oud, the most important instrument in Arabic classical music. It has grown out of my own long-time involvement in studying and playing the oud, and in particular out of my interest in the lack of sources and knowledge available to the vast majority of oud players and researchers, as well as for the readers. My own path started from an intensive study of the oud, which included exposure to several treaties; some housed in museums around the globe, and some only available in the Arabic language. The study combines archival research (including Arabic poetry and pre-Islamic Era and medieval treaties), symbolism, new archaeological discoveries, field interviews, and analysis of existing scholarship, and draws on my professional performance experience for detailed stylistic analysis of the oud's performance practice and its historical development. The study consists of participant observation, personal performance, and interviews conducted in person, via telephone, and/or via e-mail, according to the choice of the performers. The performers have been selected from networks of musicians who perform regularly at lounges, concert halls, and private events. These performers have been chosen according to their musical knowledge, technical skill, experience, and activity in Arabic music and oud performance. Chapter one deals with the purpose of this study and the methods of investigation, as well as giving a brief overview of the history of the oud. In addition, there will be an introduction to the Arabic musical system (mâqâm), which is primarily based on the mechanics and sound production of the oud. Chapter two deals with the oud in Arabic sources: the first source is Arabic poetry in the pre-Islamic Era. The second source is Arabic poetry in the medieval era, in which I found a significant number of poets who allude to the oud, providing accurate descriptions of the player, singers, and the scenes within the contexts of oud performance. The third source is the Arab scholars' intensive treatises with meticulous accounts of the instrument's apparatii, including descriptions and measurements of the parts, strings, and tuning. While chapter three deals with the classification, the development of the oud, chapter four deals with topics such as: the symbolism of the oud and its relation to cosmology, astronomy, mathematics and anatomy. In most of the pertinent Arabic writings, philosophers mention a significant correlation between the oud and the other sciences. Chapter five deals with recreating the performance practice of the oud. A case study of the oud performers focuses on their style, technique, training, and personal experiences. Topics such as improvisation and ornamentation, the oud in the Arabic musical ensemble, the social uses and functions, and gender in musical performance practices will be included in detailed analysis. Other important topics will be analyzed such as traditional vs. modern technique, and the repertoire of the oud. Specifically, in regard to technique, the study outline the style of the music, the role of the oud in Arabic ensembles, the function of the oud in music composition, and the form of the ensembles in Arabic performance and practice.

PIANIST-COMPOSERS WHOSE WORKS INCLUDE PIANISTIC INNOVATIONS

Throughout the piano’s history, certain composers have created innovations in the areas of virtuosity and sonority. These innovations came not only from the composers’ imagination, but also from the development of instruments and changes in musical style from one period to another. To investigate what kinds of innovations these pianist composers made, I divided them into technique and sound from Mozart to Cowell. I chose two-piano music (Sonata in D major, K.448 by Mozart and Rachmaninoff’s Second Suite) to demonstrate their experiments with varieties of textures and sonorities, using different registers of the two pianos orchestrally. En Blanc et noir by Debussy shows this composer’s deep interest and originality in piano sonorities. For solo piano music, Beethoven’s Piano Sonata Op.53 shows extensive technical invention. His use of long pedal effects shows a pianistic possibility not explored by Mozart. Hummel’s Piano Sonata in D major represents orchestral devices as well as pianistic techniques showing recent developments in the instrument. Chopin’s Ballade No.3 and Scherzo No.3 show virtuosic moments and also the expanded range of the keyboard. His Nocturne Op.27, no.2, with its sonorities resulting from the combination of pedal, and widespread accompaniments derived from Alberti bass figures, is a perfect example of Chopin’s characteristic sound-world. “Vallée d’Obermann” by Liszt uses many virtuosic techniques as well as the extreme wide ranges of keyboard in both hands to create dramatic contrasts of texture. Debussy’s etude, “Pour les Sonorités opposés” is probably the first etude designed for sonority rather than for keyboard virtuosity. Albeniz’s “Evocación” and “Triana” show Spanish atmosphere. Prokofiev’s Sonata no.3 shows frequent motoric driving elements that demand percussive virtuosity. Cowell’s piano music is some of the earliest to explore the sonorities of tone clusters and playing on the strings. This performance dissertation consists of three recitals performed in the Orchestra Room, Leah Smith Hall, and Gildenhorn Recital Hall at the University of Maryland, College Park. These recitals are documented on compact disc recordings that are housed within the University of Maryland Library System.