Berry Phase in Composite Fermi Liquids

Wang, Jie Princeton University ProQuest Dissertations & Thes 2019 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Two-dimensional electron gas in high magnetic field exhibits a wide variety of interesting physical properties. Perhaps most notable of these is the quantum Hall effect, which is a classic example of a topological phase. Another interesting phase occurs at even denominator filling fraction is the so-called "composite Fermi liquid". Such compressible phase is traditionally thought of as a Fermi liquid of "composite fermions" due to B. I. Halperin, P. A. Lee and N. Read (HLR).Composite Fermi liquid has gained renewed interest recently due to the particle-hole symmetry and Berry phase: when the lowest Landau level is half filled, the effective Hamiltonian is particle-hole symmetric. However, it is unclear how the HLR description realizes this symmetry. A key ingredient that was missing in HLR's treatment seems to be a PI Fermi sea Berry phase associated with transporting a composite fermion around the Fermi surface. Motivated by the symmetry and Berry phase, recently D. T. Son conjectured that composite fermions are relativistic Dirac particles. In Son's theory, particle-hole symmetry acts in a way akin to time reversal on Dirac fermions, and the PI Berry phase is a curvature singularity at Dirac node.A direct measurement of this PI Berry phase is one of the main results in this dissertation. We examined a model wavefunction that explicitly exhibits a Fermi surface, and has been shown to give good agreement with states found in exact diagonalization studies. We then formulated a many-body version of Berry phase for transporting a single composite fermion around a path in momentum space, and evaluated the Berry phase. To study the property of model wavefunction and Berry phase on larger system sizes, we developed "lattice Monte Carlo" technique based on a mathematically exact discretized formulation of holomorphic quantum Hall states on torus. Besides half filling, the Berry phase at 1/4 was found to be remarkably interesting: it suggests the emergence of Dirac fermion at generic filling fraction. Motived by this, an effective theory, dubbed as "flux attached Dirac fermion theory", which generalizes Son's theory and covers all filling fractions was proposed.

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

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

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

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.

Modeling Interparticle Interactions in Gas-Particle Flows

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

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

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)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

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.

Probing Fundamental Cosmology with Galaxy Surveys

Philcox, Oliver H.E Princeton University ProQuest Dissertations & Thes 2022 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The distribution of galaxies encodes a wealth of information about the early and late Universe, including its composition, initial conditions, and expansion history. Through the measurement of summary statistics such as the power spectrum and correlation functions, we can characterize the distribution, and thereby constrain the underlying parameters using likelihood analyses. This thesis considers a range of approaches for extracting information from large scale structure (LSS), extending previous works using new statistics, improved modeling, and enhanced analysis techniques.Firstly, we consider the galaxy power spectrum and bispectrum. Although many LSS analyses make use of the former statistic, few include the latter, owing to complexities in its measurement and modeling. In Part I of this thesis, we outline new approaches to estimate such quantities, obviating previous difficulties relating to the survey window function, and in Part II, present theoretical calculations of the power spectrum and bispectrum using the Effective Field Theory of LSS. Combining these, we can obtain precise constraints on cosmological and astrophysical parameters by fitting first-principles models to the observed statistics; in Part III, we explore the consequences for both the standard model (ΛCDM) and its extensions, in particular inflationary theories. Amongst other topics, we can shed light on the ‘Hubble tension’, utilizing measurements of the early-Universe ‘equality scale’; these results, and their cosmological interpretation, are discussed in Part IV.The remainder of this thesis is devoted to alternative approaches to describing the galaxy distribution. Part V considers a recently proposed statistic known as the marked power spectrum. Utilizing perturbation theory, we are able to understand its information content and purported utility, as well as derive rigorous models necessary to compare the statistic to observational data. Finally, Part VI describes the possibility of constraining cosmology with higher-order correlation functions via the development of efficient new estimators. These provide novel tests of the standard model: we show their ability both to constrain the gravitational four-point function and to search for hints of parity-violation in the late Universe.

Reaction-Diffusion-Deactivation in Hierarchical Zeolite Catalysts for Liquid-Phase Hydrocarbons Upgrading

Adawi, Hayat Ismail Princeton University ProQuest Dissertations & Thes 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The industrial ubiquity of crystalline Bronsted acid zeolite catalysts incentivizes their adaptation for emerging conversions, including for upgrading biomass-derived platform molecules to fuels and chemicals conventionally produced from nonrenewable petroleum. The aluminosilicate backbones of zeolites form periodic architectures with micropores of molecular diameters (dpore < 1 nm). Micropores can sieve molecules and reduce activation energies through van der Waals stabilization of confined moieties, but they can also inhibit diffusion of desired bulky species. Expanded zeolite applications necessitate structure-function studies of modified hierarchical zeolites containing auxiliary mesopores (dpore = 2-50 nm) capable of increasing catalytic efficiency by enhancing diffusion of bulky molecules.This dissertation investigated impacts of mesopores on reaction, diffusion, and deactivation in hierarchical zeolites by probing competing parallel reactions with kinetically relevant differences in effective diffusivities (De): alkylation of 1,3,5-trimethylbenzene (TMB) by benzyl alcohol (BA) to 1,3,5-trimethyl-2-benzylbenzene (TM2B), or self-etherification of BA to dibenzyl ether (DBE). These probes exclusively interrogated how steric differences (predicted from calculated confinement energies for adsorbed molecules using periodic density-functional theory) impacted observed activity, by precluding complicating interactions between zeolites' hydrophilic silanol defects and heavily oxygenated biomass. Proton-normalized reaction rates were measured for (hierarchical) zeolites synthesized from MFI, MOR, and BEA parent architectures of different crystal sizes, using post-synthetic demetallation treatments under ambient or autogenous pressures.Extracted rate constants demonstrated prevailing kinetic control for hierarchical zeolites that increased De,TMB relative to microporous zeolites with crystal radii (R) below thresholds that otherwise overinflated the relevant diffusion timescale (De,TMB/R2 ). Subsequent thermogravimetric analyses of spent catalysts revealed that graphitic coke formed from undesired polyalkylation of products preferentially deposited in micropores and dampened activity by irreversibly blocking protons. Subsequently extracted deactivation rate constants (kD) scaled logarithmically with coke accumulation. In contrast, BA, TMB, TM2B, DBE unbiasedly saturated all pores without inducing kinetically relevant deactivation. Hierarchical zeolites accommodated more coke than microporous parents at equivalent BA conversions while delaying onsets of measurable kD. These findings extend to many zeolite- and zeotype-catalyzed reactions, including ketone reduction on tin-type BEA explored in this dissertation. Ultimately, careful kinetics analysis complemented thorough catalyst characterization to inform future selection and design of heterogeneous catalysts.

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

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

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

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.

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)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

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.

Dead Center: The New Democrats and the Transformation of Liberalism

Brandon, Jacqueline Princeton University ProQuest Dissertations & Thes 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This dissertation is a history of the New Democrats, a neoliberal bloc that rose to prominence in the Democratic Party between the 1970s and the 1990s. It focuses on the centrist political figures that ushered in a new world of supply-side economics, tough-on-crime policy, stripped-down welfare, and ramped-up militarization. Laying claim to the center was a complex move in these years: the spectrum itself was shifting as the Republican Party became increasingly reactionary, dragging the whole political infrastructure to the right alongside it.Four case studies comprise the dissertation: the chapters focus on the Coalition for a Democratic Majority (CDM) in the 1970s, The New Republic magazine and the Democratic Leadership Council (DLC) in the 1980s and 1990s, and Hollywood donors to Bill Clinton's campaigns in the 1990s, before concluding with an epilogue on the 2003 invasion of Iraq. The actors-politicians and party regulars, journalists and editors, activists and strategists-spent decades hashing out where the party should stand on affirmative action, foreign policy, crime and policing, feminism, electoral reform and campaign finance. Charting the decline of the midcentury liberalism, historians tend to fix their gaze on partisanship and polarization. Conservative ascendence in electoral politics, media, popular debate, and intellectual institutions has likewise been well documented. Focusing on the extremes at both ends, scholars have neglected the machinations of the middle. This dissertation argues the liberals, too, had their ideological foot soldiers. For progressives, the realm of political possibility constricted in the last decades of the twentieth century.New Democrats sought both new constituents and new donors. Urban professionals and suburban swing voters supplanted the party's historic blue-collar base. The actors in this dissertation are united in their conviction that Democrats could finally, at long last, find a way out of the political wilderness of the Nixon and Reagan eras by courting would-be Republican voters. Dead Center is also about moderates' shifting relationship to the New Left, as the anti-identity politics dogma of the 1970s was supplanted by a politics of recognition and multiculturalism that came to characterize the mainstream of the party by the 1990s.

The Synthetic Tongue: Speech, Writing, and "Speech Writings" in Early China

Yao, Zhuming Princeton University ProQuest Dissertations & Thes 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Many early Chinese writings feature a scene of speech. In more literary writings as in more technical ones, writing often puts in the mouth of a speaker what the text tries to get across. Frequently, the speaker's spoken words, comprising a text either in full or in part, also occupy the center stage of writing's attempt at narrating a story, arguing a point, imparting a skill, or simply sorting things out. The list goes on. This lasting, shared, and versatile appeal to, and of, the spoken word in early Chinese writings is the topic of this dissertation. It argues that speech representation is first and foremost a narrative device serving a text's rhetorical aims. Writing does not represent speech as a mere technology of transcription; rather, writing creates a world-in-itself with and through the representation of speech, a highly elevated medium of expression since early on. In the process, this dissertation also shows, there developed a set of representational structures and narrative techniques with which speech representation was approached. The former supply writing with the forms, shapes, and tropes that underlie the representation of speech; the latter the means to make creative but circumscribed variations. Together, they cement the role of the spoken word as a narrative construct that different writings can use and adapt for their own rhetorical purposes. In highlighting these aspects of the spoken word, this dissertation offers an account of a core but underemphasized attribute of early Chinese textuality, models a new methodological approach, and proposes a range of interpretations of texts old and new intended to reevaluate their meaning and significance. Its goal, ultimately, is to promote a new way of reading.