Nonlinear quantum transport in low-dimensional electronic devices

The study of transport processes in low-dimensional semiconductors requires a rigorous quantum mechanical treatment. However, a full-fledged quantum transport theory of electrons (or holes) in semiconductors of small scale, applicable in the presence of external fields of arbitrary strength, is still not available. In the literature, different approaches have been proposed, including: (a) the semiclassical Boltzmann equation, (b) perturbation theory based on Keldysh's Green functions, and (c) the Quantum Boltzmann Equation (QBE), previously derived by Van Vliet and coworkers, applicable in the realm of Kubo's Linear Response Theory (LRT). ^ In the present work, we follow the method originally proposed by Van Wet in LRT. The Hamiltonian in this approach is of the form: H = H 0(E, B) + λV, where H0 contains the externally applied fields, and λV includes many-body interactions. This Hamiltonian differs from the LRT Hamiltonian, H = H0 - AF(t) + λV, which contains the external field in the field-response part, -AF(t). For the nonlinear problem, the eigenfunctions of the system Hamiltonian, H0(E, B), include the external fields without any limitation on strength. ^ In Part A of this dissertation, both the diagonal and nondiagonal Master equations are obtained after applying projection operators to the von Neumann equation for the density operator in the interaction picture, and taking the Van Hove limit, (λ → 0, t → ∞, so that (λ2 t)n remains finite). Similarly, the many-body current operator J is obtained from the Heisenberg equation of motion. ^ In Part B, the Quantum Boltzmann Equation is obtained in the occupation-number representation for an electron gas, interacting with phonons or impurities. On the one-body level, the current operator obtained in Part A leads to the Generalized Calecki current for electric and magnetic fields of arbitrary strength. Furthermore, in this part, the LRT results for the current and conductance are recovered in the limit of small electric fields. ^ In Part C, we apply the above results to the study of both linear and nonlinear longitudinal magneto-conductance in quasi one-dimensional quantum wires (1D QW). We have thus been able to quantitatively explain the experimental results, recently published by C. Brick, et al., on these novel frontier-type devices. ^

The (Wo)Man in the Masque: Cross-Dressing as Disguise in Early Modern English Literature

Characters’ identities are integral to how audiences relate to them. But what happens when the character suddenly alters his or her outward appearance? Are they still the same person? This thesis seeks to argue that disguise does not alter a character’s true nature, as evidenced by Pyrocles in Sir Philip Sidney’s The Countess of Pembroke’s Arcadia and the Prince in Margaret Cavendish’s The Convent of Pleasure. Both Pyrocles’ suit of Philoclea and the Prince’s suit of Lady Happy are successful because, however subversive they appear at first, they ultimately adhere to societal norms of the time. The relationship between the cross-dressed prince and his love interest in both works only appears to subvert heteronormative expectations for the time, but ultimately adheres to these societal norms once the disguised character’s true identity is revealed to his chosen partner.

Children's Literature, Ideology, and Cultural Identity Before and After the Cuban Revolution

Mediante de un acercamiento cronológico, esta disertación analiza la función de la ideología como herramienta poderosa para construir la nación y moldear al futuro ciudadano en la narrativa infantil cubana pre y pos-revolucionaria. Aunque una tradición y un proceso de formación de identidad nacional anteceden la literatura infantil publicada antes del triunfo de la Revolución, en los períodos posteriores existe una estrecha relación entre el contexto social de los textos y su función ideológica. Partiendo de “La Edad de Oro” (1889) de José Martí, este estudio se enfoca en los cambios socio-culturales que influyen en el desarrollo de una narrativa infantil nacional que transita del didacticismo más férreo a una variada exploración temática. Por encontrarse entre la Colonia y la etapa revolucionaria, el período republicano ha recibido poca atención crítica, marginado a veces de la herencia literaria de la nación. Sin embargo, el análisis de varios textos representativos en este período permite apreciar la integración de un pensamiento cubano desde búsquedas y posiciones muy diferentes a las del período siguiente, de 1959 a 1989. A partir de 1990 una diversificación temática fomenta objetivos muy distantes del enunciado didáctico. Este estudio concluye que en contraste con los pertenecientes a generaciones anteriores, en los escritores formados dentro de la Revolución, especialmente a partir de la década del ochenta, existe un interés especial por abordar temáticas inexploradas en la literatura infantil tradicional. El divorcio, la muerte, los conflictos generacionales y las diferencias raciales son sólo algunos de los temas que matizan la narrativa infantil posrevolucionaria, cuyos presupuestos ideo-estéticos, se encuentran intrínsecamente relacionados al contexto sociocultural.

Nonlinear quantum transport in low-dimensional electronic devices

The study of transport processes in low-dimensional semiconductors requires a rigorous quantum mechanical treatment. However, a full-fledged quantum transport theory of electrons (or holes) in semiconductors of small scale, applicable in the presence of external fields of arbitrary strength, is still not available. In the literature, different approaches have been proposed, including: (a) the semiclassical Boltzmann equation, (b) perturbation theory based on Keldysh's Green functions, and (c) the Quantum Boltzmann Equation (QBE), previously derived by Van Vliet and coworkers, applicable in the realm of Kubo's Linear Response Theory (LRT). In the present work, we follow the method originally proposed by Van Vliet in LRT. The Hamiltonian in this approach is of the form: H = H°(E, B) + λV, where H0 contains the externally applied fields, and λV includes many-body interactions. This Hamiltonian differs from the LRT Hamiltonian, H = H° - AF(t) + λV, which contains the external field in the field-response part, -AF(t). For the nonlinear problem, the eigenfunctions of the system Hamiltonian, H°(E, B) , include the external fields without any limitation on strength. In Part A of this dissertation, both the diagonal and nondiagonal Master equations are obtained after applying projection operators to the von Neumann equation for the density operator in the interaction picture, and taking the Van Hove limit, (λ → 0 , t → ∞ , so that (λ2 t)n remains finite). Similarly, the many-body current operator J is obtained from the Heisenberg equation of motion. In Part B, the Quantum Boltzmann Equation is obtained in the occupation-number representation for an electron gas, interacting with phonons or impurities. On the one-body level, the current operator obtained in Part A leads to the Generalized Calecki current for electric and magnetic fields of arbitrary strength. Furthermore, in this part, the LRT results for the current and conductance are recovered in the limit of small electric fields. In Part C, we apply the above results to the study of both linear and nonlinear longitudinal magneto-conductance in quasi one-dimensional quantum wires (1D QW). We have thus been able to quantitatively explain the experimental results, recently published by C. Brick, et al., on these novel frontier-type devices.

Extended program notes for a recital of selected vocal literature

The purpose of these extended program notes is to provide information that will assist the listening audience in comprehending the historical and biographical significance of the each vocal selection. A brief analysis of each selection, a historical interpretation of the work, a translation of the texts and a CD of the recital are included. The contents of the recital comprise of several selections from the soprano repertoire: The Georg Phillip Telemann cantata Lauter Wonne, lauter Freude; the Wolfgang Amadeus Mozart Laudate Dominum from the Vesperae solemnes de confessore; the Joaquin Nin y Castellano Diez Villancicos de Noel; Gabriel Faurd's art songs Dans le ruines d'une abbay, Les Berceaux, and Au bord e l'eau; Sergei Rachmaninov's three songs Oni otvechali, Zdes Khorosho, and Vocalise; and Libby Larsen's Cowboy Songs.

The Effects on Students' Self-Efficacy Beliefs Regarding Their Comprehension of American Literature When Aesthetic Reading and Reader Response Strategy are Implemented

High-stakes testing and accountability have infiltrated the education system in the United States; the top priority for all teachers must be student progress on standardized tests. This has resulted in the predominance of reading for test-taking, (efferent reading), in the English, language arts, and reading classrooms. Authentic uses of print activities, like aesthetic reading, that encourage students to engage individually with a text, have been pushed aside. During a 3-week time period, regular level, English 3/American literature students in a Title I magnet high school, participated in this quasi-experimental study (N = 62). It measured the effects of an intervention of reading American literature texts aesthetically and writing aesthetically-evoked reader responses on students’ self-efficacy beliefs regarding their comprehension of American literature. One trained teacher and the researcher participated in the study: student participants were pre- and post- tested using the Confidence in Reading American Literature Survey which examined their self-efficacy beliefs regarding their comprehension of American literature. Several statistical analyses were performed. The results of the linear regression analyses partially supported a positive relationship between aesthetically-evoked reader responses and students’ self-efficacy beliefs regarding their comprehension of American literature. Additionally, the results of the 2 (sex) x 2 (treatment) ANCOVAs conducted to test group differences in self-efficacy beliefs regarding the comprehension of American literature between treatment and control groups indicated a main effect for treatment (but not sex; nor was there a significant sex x treatment interaction), suggesting the treatment was partially effective in increasing students’ self-efficacy beliefs. Seven of the twelve ANCOVAs indicated a statistically significant increase in the treatment group’s adjusted group mean self-efficacy belief scores as a result of being exposed to the intervention. In six of these seven analyses, increases in self-efficacy beliefs occurred in tasks that required three or more higher-order levels of thinking/learning. The results are discussed in terms of theoretical, empirical and practical significance. Future research is recommended to extend the intervention beyond the narrow confines of a Title I magnet school to settings where the intervention could be tested longitudinally, e. g., honors and gifted students, elementary and middle schools.

A Critique of the Representation of Violence in American Literature:

The purpose of this thesis was to draw new insights on Thomas Berger’s classic American novel, Little Big Man, and his representation of fictional violence that is a substantial aspect of any text on the Indian Wars and “Custer’s Last Stand”. History’s major world wars led to shifts in the political climate and a noted change in the way that violence was represented in the arts. Historical, fictional, and cinematic treatments of “Custer’s Last Stand” and violence were each considered in relation to the text. Berger's version of the famed story is a revision of history that shows the protagonist as a dual-member of two violent societies. The thesis concluded that Berger’s updated American legends and unique “white renegade” character led to a representation of violence that spoke to the current state of affairs in 1964 when the world was becoming much more hostile and chaotic place.

A Comparison Study of the English III/American Literature Success of African American High School Students and That of Students Whose Home Language is Haitian Creole

The purpose of the study was to compare the English III success of students whose home language is Haitian Creole (SWHLIHC) with that of the more visible African American high school students in the Miami Dade County Public Schools System, in an effort to offer insight that might assist educators in facilitating the educational success of SWHLIHC in American Literature class. The study was guided by two important theories on how students interact with and learn from literature. They are Reader Response Theory which advocates giving students the opportunity to become involved in the literature experience (Rosenblatt, 1995), and Critical Literacy, a theory developed by Paolo Freire and Henry Giroux, which espouses a critical approach to analysis of society that enables people to analyze social problems through lenses that would reveal social inequities and assist in transforming society into a more equitable entity. Data for the study: 10th grade reading FCAT scores, English III/American Literature grades, and Promotion to English IV records for the school year 2010-2011 were retrieved from the records division of the Miami Dade County Public Schools System. The study used a quantitative methods approach, the central feature of which was an ex post facto design with hypotheses (Newman, Newman, Brown, & McNeely, 2006). The ex post facto design with hypotheses was chosen because the researcher postulated hypotheses about the relationships that might exist between the performances of SWHLIHC and those of African American students on the three above mentioned variables. This type of design supported the researcher’s purpose of comparing these performances. One way analysis of variance (ANOVA), two way ANOVAs, and chi square tests were used to examine the two groups’ performances on the 10th grade reading FCAT, their English III grades, and their promotion to English IV. The study findings show that there was a significant difference in the performance of SWHLIHC and African American high school students on all three independent variables. SWHLIHC performed significantly higher on English III success and promotion to English IV. African American high school students performed significantly higher on the reading FCAT.