Stimulated Raman Back-Scattering and Self-Guiding of Femtosecond Laser Pulses

Chen, Qiang Princeton University ProQuest Dissertations & Thes 2019 해외박사(DDOD)

Plasma has been proposed as the amplification medium for the next generation of ultra-high intensity lasers as it can sustain several orders of magnitude higher intensities than the thermal damage threshold of the solid-state optical elements, which is below 1012Wcm-2. Plasma-based Stimulated Raman Back-Scattering, SRBS, also known as Raman Amplification, seems to be a very efficient approach, although an energy transfer efficiency to the amplified seed did not reach 10% yet. Experiments and simulations on increasing efficiency and exploring better control of SRBS seed amplification were conducted at Princeton University. For example, particle-in-cell simulations help reveal the splitting of the amplified seed as a result of resonance slipping induced by the large pump chirp. In addition, a new scheme for SRBS was proposed, Stimulated Raman Near-Back-Scattering (SRNBS), while using a three-wave model, in which, by varying the pulse-front tilt angle of the pump, the length of the pump beam passing a plasma can be controlled. As a result, this new scheme may efficiently enhance the amplification, and at the same time, it could reduce the spontaneous Raman radiation that may pre-deplete the pump pulse. Simulations using the three-wave model was also applied to better understand the novel double-pass SRBS experiments. Landau damping and the frequency shift of Langmuir waves were identified as possible reasons for the low efficiency of single-pass amplifiers. In the double-pass scheme, those problems can be alleviated, due to plasma cooling between the two passes. Ionization assisted self-guiding of very tightly focused beams for more than 30 Rayleigh lengths was demonstrated with the transmission up to $80\%$. A cylindrical shock wave is necessary for the self-guiding and it is generated following the expansion of the plasma filament created by a laser line focus. As an intense femtosecond laser pulse propagates inside the shock wave, a small portion of the pulse's leading edge ionizes the neutrals near the inner wall of the cylindrical shock wave. Such created free electrons form a guiding structure for the trailing part of the pulse, which could enhance some laser-plasma interactions, including the recombination X-ray lasers developing in our lab.

Modeling Interparticle Interactions in Gas-Particle Flows

Liu, Xiaoyu Princeton University ProQuest Dissertations & Thes 2022 해외박사(DDOD)

Flows of gas-particle mixtures are ubiquitous in nature and in various processes. Interparticle interactions, including van der Waals’ (vdW) interactions and electrostatic interactions, can significantly impact gas-particle flows through agglomeration, defluidization, and particle segregation. This dissertation focuses on modeling the effect of vdW interactions and electrostatic interactions on the dynamics of gas-particle flows.Particles pick up and exchange electrostatic charges through tribocharging, a process which is essential for modeling electrostatic interactions. We first develop and test a tribocharging model that can be coupled with particle flow simulations and used to probe the effect of charging on gas-particle flows. We study the effect of particle size on tribocharging through a combination of vibrated bed experiments and Discrete Element Method (DEM) simulations of systems with different particle sizes, domain sizes, and wall materials and develop a phenomenological model that can capture this effect. In a similar approach, we investigate the effect of ambient gas on tribocharging using vibrated bed experiments and complementary DEM simulations and show that charge difference in different gases can be captured by imposing the gaseous dielectric strength as an additional constraint in the tribocharging model. We then discuss the modeling of dry powder inhalers (DPIs), a complex gas-particle system consisting of a very large number of particles. Since highly-resolved Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) is computationally expensive, we assess the efficacy of Discrete Parcel Method and the representative particle approach proposed in this dissertation. We discuss the viability and limitations of both approaches in a model inhaler by only considering vdW interactions and demonstrate the advantage of the representative particle approach. We finally present a computational study of agglomerate-wall collision tests considering both vdW and electrostatic interactions and show that deagglomeration is primarily affected by vdW interactions.

Political-Military Integration The Relationship Between National Security Strategy and Changes in Military Doctrine in the United States Army and Marine Corps

Haelig, Carlton G Princeton University ProQuest Dissertations & Thes 2023 해외박사(DDOD)

This dissertation analyzes the interaction of changes in national security strategy with changes in individual military services' operational concepts and doctrine. It expands on existing analyses of changes in American grand strategy by focusing specifically on the responses of the United States military services to those changes. While a robust body of work exists on strategy and military innovation, much less research exists on the relationship between the two. The dissertation's theoretical framework explains how changes in grand strategy affect changes in military service behavior, how and why military services push back against changes in grand strategy, and how military services may independently influence changes in grand strategy by developing new warfighting and power projection capabilities. This dissertation draws on theory-based historical analysis to execute comparative case study research designs using archival sources- many of them recently declassified and being used in academic research for the first time. It relies on organizational theory, bureaucratic politics, civil-military relations, and international security studies to develop a set of hypotheses regarding when and why we should expect to see particular reactions from a given military service to a change in security strategy. These responses range from inaction or insubordination to pursuing radical change meant to integrate the service with new strategic objectives. Crucially, these outcomes also vary depending on the type of grand strategy pursued and how civilian officials implement that strategy. The empirical analysis includes seven case studies ranging from the Army and Marine Corps responses to the New Look strategy enacted in 1953 to the Army and Marine Corps efforts to shape American strategy in the 1980s with their respective AirLand Battle and Maneuver Warfare concepts.

Escritura privada y subjetividad publica en America Latina: Entre el diario politico y el diario de autor (1895–2017) : Private Writing and Public Subjectivity in Latin America: Between the Political Diary and the Author’s Diary (1895–2017)

Lebron Rivera, Rodney Princeton University ProQuest Dissertations & Thes 2025 해외박사(DDOD)

Escritura privada y subjetividad publica en America Latina: Entre el diario politico y el diario de autor (1895-2017) examines four Latin American diaries to explore how the diary functions as an artifact that synthesis heterogeneous temporalities while simultaneously allowing a specific authorial role through an auto-figurative technology across various contexts.This doctoral dissertation analyzes the diaries of Jose Marti, Jose Juan Tablada, Lorenzo Garcia Vega, and Ricardo Piglia, aiming to contribute interpretively to a cultural field where the diary is primarily understood in its testimonial aspect, viewed as a documentary source. Through systematic and typological analysis, this thesis will demonstrate that the diary in modern Latin American literature is not merely a narrative of an author's daily life, but also a way of reading and writing, utilizing the first person, and functioning as an artifact that enables a specific form of enunciation.Given its intrinsic relationship with time, and situating diary writing within its historical context, this study seeks to reveal how Latin American diaries can be analyzed through various typologies to highlight the heterogeneity of an artifact that is often deemed "secondary," "marginal," and "circumstantial" in the field of Latin American literature. The corpus of diaries analyzed varies according to historical context, with chapters organized based on historical temporality and the dissertation's central argument: to examine the internal mechanisms of the diary within the frameworks of the diario politico and diario de autor typologies, illustrating the constant transmutations of fragmentary writing marked by calendar days. Additionally, this dissertation will occasionally consider other textual forms by diary writers, such as essays, journalistic chronicles, novels, and short stories. scritura privada y subjetividad publica en America Latina: Entre el diario politico y el diario de autor (1895-2017) examines four Latin American diaries to explore how the diary functions as an artifact that synthesis heterogeneous temporalities while simultaneously allowing a specific authorial role through an auto-figurative technology across various contexts.This doctoral dissertation analyzes the diaries of Jose Marti, Jose Juan Tablada, Lorenzo Garcia Vega, and Ricardo Piglia, aiming to contribute interpretively to a cultural field where the diary is primarily understood in its testimonial aspect, viewed as a documentary source. Through systematic and typological analysis, this thesis will demonstrate that the diary in modern Latin American literature is not merely a narrative of an author's daily life, but also a way of reading and writing, utilizing the first person, and functioning as an artifact that enables a specific form of enunciation.Given its intrinsic relationship with time, and situating diary writing within its historical context, this study seeks to reveal how Latin American diaries can be analyzed through various typologies to highlight the heterogeneity of an artifact that is often deemed "secondary," "marginal," and "circumstantial" in the field of Latin American literature. The corpus of diaries analyzed varies according to historical context, with chapters organized based on historical temporality and the dissertation's central argument: to examine the internal mechanisms of the diary within the frameworks of the diario politico and diario de autor typologies, illustrating the constant transmutations of fragmentary writing marked by calendar days. Additionally, this dissertation will occasionally consider other textual forms by diary writers, such as essays, journalistic chronicles, novels, and short stories.

Worldmaking in Music, Sound Art, and Instrument Design

Elliot, Liam David Princeton University ProQuest Dissertations & Thes 2025 해외박사(DDOD)

The audio arts, and music in particular, have often been understood according to a narrative concept based on a dramatic arc of conflict and resolution. I propose that a body of work exists that is better understood as an act of worldmaking in which artworks exist as assemblages of continuous process. This thesis explores ways in which the idea of worldmaking has shaped artistic practices in the audio arts. It begins by proposing a theoretical framework based primarily on the work of Ursula K. Le Guin and Anna Tsing, then examines how these ideas have been applied in the work of several composers, sound artists, and instrument designers.In music, Pauline Oliveros, Brian Eno, and Hildegard Westerkamp have each created bodies of work that have been influential on the practice of worldmaking in music. I examine the concepts underpinning their individual practices as well as the larger cultural movements that they have each contributed to before moving on to the distinct but related musical ideas of John Luther Adams and Anna Þorvaldsdottir, focusing on their immersive instrumental works Inuksuit and METAXIS.In addition to his work as a composer, Adams has also created sound installations that sonify natural systems. I explore how the indefinite nature of sound installations affects their ability to create a sense of place by comparing Adams' The Place Where You Go To Listen with Andrea Polli's Atmospherics/Weather Works and with other sound installations based on nature data.Finally, I discuss the application of worldmaking concepts to instrument design. I begin with a broad discussion of the modular synthesizer as an assemblage instrument, then examine two instruments that demonstrate distinct approaches to worldmaking: Peter Blasser's Plumbutter, and Tyler Etters' Arcologies.The portfolio section of this dissertation includes my composition a body in a place, my sound installation Sound Fisher, my electro-acoustic instrument Resin, and my software instrument Flyway. Together, these provide an illustrative overview of my creative work at Princeton.

Enabling Practical Quantum Computation: Compiler and Architecture Techniques for Bridging the Algorithms-to-Devices Resource Gap

Murali, Prakash Princeton University ProQuest Dissertations & Thes 2021 해외박사(DDOD)

Quantum computing (QC) is an emerging computational paradigm poised to fundamentally change what is computable in material science, machine learning, optimization, and other domains. From the first 1- and 2-qubit systems in the early 2000s, today's QC hardware landscape includes cloud-accessible systems with 10-50 qubits and multiple qubit technology candidates for large-scale QC. In spite of rapid hardware progress, the first practically useful QC applications have not been demonstrated yet, even though hundreds of QC algorithms have been developed in the last three decades. This is fundamentally because of a large gap between the resource requirements of QC applications and the capabilities of quantum hardware that is buildable in the near-term; qubit counts and operational noise constraints of applications exceed hardware capabilities by 5-6 orders of magnitude. This dissertation seeks to close the resource gap between quantum algorithms and hardware. The resource gap in QC is similar to the resource gap that existed in classical computing in the 1950s. Taking inspiration from the vital role played by computer architecture in scaling up classical computers, this dissertation develops quantum compilation and architectural techniques. Unlike prior research efforts which largely focused on designing individual layers in the QC execution stack in isolation, this dissertation develops a cross-cutting design approach to optimize the QC stack. Using this approach, Part I of this dissertation develops techniques to bridge the applications-to-devices resource gap from the top of the stack and Part II develops techniques to bridge the gap from the bottom of the stack.Part I includes noise-adaptive compilation techniques that adapt program executions to the large spatial and temporal noise variations that occur in near-term QC systems. Part I also includes the first software technique to mitigate the impact of crosstalk noise on applications. The techniques presented in Part I offer one to two orders of magnitude improvements in application fidelity compared to vendor compiler toolflows and related works. Part II includes an extensive study of architectural designs of real QC systems, a study on designing trapped ion systems based on application requirements and a study on instruction set design to balance application and hardware needs. Through hardware-software co-design, Part II offers up to four orders of magnitude (i.e., 10000X) improvement in reliability for near-term QC devices. This dissertation has already influenced several industry toolflows and architectures. Noise-adaptivity is now a standard optimization in industry compilers, including IBM's Qiskit, Rigetti's Quilc, Cambridge Quantum Computing's TKET and Oak Ridge National Laboratory's XACC and QCOR toolflows. IBM's Qiskit compiler also incorporated this dissertation's crosstalk mitigation techniques. This dissertation's instruction set design recommendations have also been adopted by IBM and these recommendations were instrumental in achieving a quantum volume of 64 on their hardware. Further, the architectural study in Part II was instrumental in driving the community towards application-level benchmarking instead of relying only on low-level benchmarking and metrics like qubit counts. In summary, this dissertation shows that cross-cutting design offers several orders of magnitude improvement in reliability and performance for QC systems, compared to existing approaches. We expect that this approach will be beneficial both for near-term NISQ hardware and the longer-term systems that follow. The research contributions and directions laid out in this dissertation have the potential to accelerate the progress towards practically viable QC by several years, rather than relying solely on hardware or application improvements.

The Muse of Pedagogy: Metaphors of Education in Nineteenth-Century Russian Literature

Matthews, Laura Elisabeth Princeton University ProQuest Dissertations & Thes 2022 해외박사(DDOD)

This dissertation explores the metaphors for education employed by three nineteenth-century Russian writers, Aleksandr Sergeevich Pushkin, Sergei Timofeevich Aksakov, and Lev Nikolaevich Tolstoy. These metaphors reflect not only the pedagogical philosophy of these writers in a single cohesive image, but also the major tenets of their worldviews, thereby providing a window into their ideologies, literary stylistics, and views on the relationship between literature and education. Each chapter focuses on a close reading of a text onto which the author’s metaphorical construct of education can shed new light. I examine Pushkin’s “school of life” metaphor in his memorandum “On National Education”, Aksakov’s metaphor of the little scarlet flower’s growth in The Childhood Years of Bagrov’s Grandson, and Tolstoy’s dueling metaphors for education, the watermill and the windmill, in Anna Karenina. By unpacking the entailments, or implications and inferences, of each metaphor, we discover not only the key to understanding the texts in which they reside, but also a new way of viewing the authors and their literary production. Applying metaphor theory and contemporary educational scholarship of metaphors to our literary analysis of these writers’ works enables us to uncover why authors turn to metaphors – instead of to literal pedagogical discourse and terminology such as obrazovanie, vospitanie, and razvitie – to communicate their views most effectively. The nature of metaphor as a way of knowing, a means of communication, and a contributor to the construction of reality will illuminate this device’s function in the works of our authors and lead to productive ways of understanding metaphor that have implications on pedagogy and teaching practice today. In addition to highlighting new contours of the life and work of Pushkin, Aksakov, and Tolstoy, this dissertation’s objectives are threefold: illustrate the prominence of pedagogy as a major concern of the nineteenth-century Russian literary community, demonstrate the efficacy of metaphors as a means of communicating pedagogical knowledge, and make a case for examining educational metaphors in literature to train and equip educators today to do the same with their own constructs of education.

Cobalt-Catalyzed Asymmetric Hydrogenation of Alkenes: Catalyst Developments and Mechanistic Investigations

Zhong, Hongyu Princeton University ProQuest Dissertations & Thes 2021 해외박사(DDOD)

Transition metal-catalyzed hydrogenation reactions represent one of the cornerstones in homogeneous catalysis. The asymmetric hydrogenation of unsaturated molecules is an atom-economical method for the synthesis of enantio-enriched compounds and is of particular interest to the pharmaceutical, agrochemical and fine chemical industries. Catalysts based on second- and third-row transition metals, including rhodium, iridium and ruthenium, have been intensively studied in the past five decades and applied widely in industries. Thorough mechanistic studies have been carried out, facilitating catalyst designs and process optimizations. There has been a growing interest in developing relatively Earth abundant, 3d transition metal hydrogenation catalysts based on manganese, iron, cobalt and nickel as alternatives to 4d and 5d transition metals owing to their reduced cost, uninterrupted supply chains and relatively lower toxicity. First-row metals have kinetically and thermodynamically accessible oxidation states separated by one-electrons, which offers opportunities for catalyst designs with new reaction mechanisms. Despite recent progress, the understandings of catalyst speciation upon in situ activation are still limited. Elucidating the coordination chemistry, oxidation states and spin states of active catalysts is of fundamental importance to inform catalyst designs and improve the catalytic performance of first-row metals.In this dissertation, the synthesis, characterization and mechanistic studies of a host of cobalt catalysts for the asymmetric hydrogenation of carbon–carbon double bonds will be introduced. In particular, cobalt catalysts supported by chiral bidentate phosphine ligands have been identified as a “privileged” class of catalysts and will be the focus of this dissertation.The cobalt-catalyzed asymmetric hydrogenation affording the epilepsy medication, levetiracetam, has been developed and applied to a 200-gram, pilot scale hydrogenation. The unique stability and high activity of reduced cobalt catalysts in protic solvents represent major advances for first-row alkene hydrogenation catalysts. The reaction mechanisms of enamide asymmetric hydrogenation with the formally cobalt(0) catalysts were investigated by experimental and computational methods. The enantioselectivity originates from the different reactivity of a pair of diastereomeric bis(phosphine)cobalt(0)–enamide complexes with H2. The cobalt-catalyzed asymmetric hydrogenation of α, β-unsaturated carboxylic acids with unusual homolytic H2 cleavage has been achieved, affording chiral acid products including Naproxen, Flurbiprofen and an L-DOPA precursor. The reactions between bis(phosphine)cobalt(II) dialkyl precatalysts and alcohols have been investigated and the bis(phosphine)Co(II) alkoxide products remained catalytically active. A cobalt-promoted methanol dehydrogenation reaction was also studied. The long-sought-after cobalt analogs of Schrock-Osborn type rhodium catalysts have been synthesized and characterized. A cationic bis(phosphine)cobalt(I) arene catalyst was discovered to be highly active for the asymmetric hydrogenation affording the type 2 diabetes medication, Sitagliptin. The ligand substitution of bis(phosphine)cobalt(0)(diene) catalysts was investigated using kinetic methods establishing a dissociative substitution mechanism. Solid state parameters and electronic structure studies imply their alternative assignment as bis(phosphine)cobalt(II) metallacyclopropane, providing a rationale for the unique protic stability. A family of cobalt precatalysts supported by the bis(phosphine), (R,R)-BenzP*, has been synthesized and characterized. The magnetic properties of dimeric bis(phosphine)Co(I)monochloride precatalysts have also been elucidated.

Reconfigurable Hardware Acceleration with Synthesizable and Tightly Integrated FPGAs

Li, Ang Princeton University ProQuest Dissertations & Thes 2024 해외박사(DDOD)

The stagnant growth of general-purpose processors' performance has led to the rise of hardware acceleration, while the high non-recurring engineering costs of application-specific hardware accelerators have increased the popularity of field-programmable gate arrays (FPGAs). The growing diversity in FPGA applications motivates the design of domain-optimized FPGAs and their integration with other processing units like processors. These two research topics constitute the focus of this dissertation.Conventionally, FPGAs are built with customized electronic design automation (EDA) tools and large collections of custom-layout circuits. Therefore, it is costly and time-consuming to evaluate different FPGA architectures with transistor-level fidelity, let alone silicon prototyping or agile productionization of novel FPGAs. Addressing this issue, this thesis investigates synthesizable FPGAs that can be designed with off-the-shelf EDA tools. This thesis first presents the Princeton Reconfigurable Gate Array (PRGA), an open-source FPGA research and prototyping framework. Per userspecification, PRGA generates the synthesizable Verilog descriptions of a custom FPGA and all the necessary scripts to configure several other open-source FPGA tools into a complete Verilog-to-bitstream toolchain for the custom FPGA. Leveraging PRGA, this thesis then proposes an algorithm for designing intrinsically cycle-free FPGAs, enabling automated optimization and accurate characterization using off-the-shelf EDA tools. Cycle-free FPGAs offer comparable routability and performance to conventional synthesizable FPGAs while consuming less area.In complement to optimizing FPGA architectures, this thesis proposes a cache-coherent, manycore-FPGA system named Duet. Unlike commercial CPU-FPGA system-on-chips (SoC) in which a few processors play a supportive role for a single, monolithic embedded FPGA (eFPGA), Duet integrates multiple, possibly heterogeneous eFPGAs with a manycore processor, enabling two paradigms of acceleration: fine-grained acceleration, which partitions an application into small tasks and offloads the compute-intensive ones onto eFPGA-emulated accelerators, leaving the less accelerable tasks to the processors; hardware augmentation, which employs eFPGA-emulated hardware widgets to improve processor efficiency in certain execution models.The synthesizable FPGA design methodology and the Duet system are evaluated with two SoC prototypes, CIFER and DECADES, both fabricated in a Global-Foundries 12nm FinFET technology. This thesis details the design and characterization of the eFPGAs and CPU-FPGA interfaces on the two chips.

Bicubical Directed Type Theory

Weaver, Matthew Zachary Princeton University ProQuest Dissertations & Thes 2024 해외박사(DDOD)

In homotopy type theory, each type is equipped with an abstract notion of path, corresponding to the morphisms of a ∞-groupoid. Voevodsky's univalence axiom states that the type of paths between types is equivalent to the type of equivalences between types, and can be seen as extending type theory with a generic program for lifting equivalences between types along any type family. Defining this lifting for all dependent types is quite subtle, but univalence has now been given a computational interpretation in various cubical type theories.A natural question is whether there are any directed analogues of homotopy type theory, where types are equipped with a notion of directed morphism and correspond to higher categories, generalizing groupoids. In such a setting, one possible directed analogue of univalence would circumscribe a class of type constructors that represent covariant functors, and provide a means to automatically lift a function or directed morphism along such a type constructor. Directed type theory with directed univalence has some potential applications to computer science that are not possible in ordinary homotopy type theory, such as providing a convenient language for coding the functorial specification of abstract syntax.One approach to directed type theory, developed by Riehl and Shulman, is based on equipping each type with both a notion of path and a separate notion of directed morphism. While ordinary homotopy type theory has models in simplicial sets, the Riehl-Shulman type theory is modeled in bisimplicial sets, capturing these two notions of path and directed morphism. While this suffices for formalizing mathematics, for applications to computer science we would like a computational interpretation of the type theory, and it is not yet known whether there are constructive models of homotopy type theory in simplicial sets.Thus we instead consider a cubical setting, and give a constructive model of a directed type theory with directed univalence in bicubical sets. We formalize much of this using Agda as the internal language of a topos, following Orton and Pitts.First, building on the cubical techniques used to give computational models of homotopy type theory, we show that there is a universe of covariant discrete fibrations with a partial directed univalence principle asserting that functions are a retract of morphisms in this universe. To complete this retraction into an equivalence, we refine the model using Coquand, Ruch, and Sattler's work on constructive sheaf models. We introduce the cobar modality and by restricting to fibrant types that are also cobar modal, we are able to complete our construction of directed univalence.We then describe a generalization of the fibrant Riehl-Shulman extension types defined in [62]. We prove this in the setting of an arbitrary presheaf category with respect to a new notion of fibrancy that is given by a generic filling problem. This abstraction is general enough to capture all of the current presheaf models of type theories and their classifications of types specified by filling problems. In addition, this result extends the potential syntax of these type theories to be able to internally express any of these filling problems as fibrant types. We use this to then define a type theory in which the user can internally define classifying universes for any such filling problem.Lastly, we overview our implementation of bicubical directed type theory focusing on a few interesting design decisions in regards to its syntax. As opposed to exposing the connections for the directed interval we chose to instead include inequality cofibrations directly in the syntax and omit connections, resulting in a syntax that is sufficiently expressive while providing substantial benefits computationally.