VictorJuiz/thesis huggingface dataset:
Room temperature polariton platform by nanoconfined synthesis

Quantum fluids, from superconducting electrons to superfluid helium, from BEC ultracold atoms on optical lattices, to cosmological-scale superfluid core in neutron stars, embody the most profound quantum behaviors of a many-particle world. The theories which explained such incredible phenomena count among the greatest achievements in theoretical many-body physics, and have had profound implications in many other areas, such as the standard model of particle physics. Gain-dissipative exciton-polaritons systems have recently emerged as promising solid-state platforms for complex quantum many-body simulations. However, a room-temperature polariton platform remains a holy grail due to material limitations. This dissertation presents a consistent endeavor to construct a robust room-temperature exciton-polariton platform using solution-based nanoconfined synthesis and study these fascinating quantum fluid phenomena./nThe first part of the dissertation developed a solution-based single crystal growth method by the combination of top-down nanofabrication and bottom-up chemical synthesis in the fabricated two-dimensional confined nanocavity. We demonstrate crystal growth under such nanometer confinement shows four major unique advantages, namely, nanometer-precise thickness control, large grain size, excellent excitonic quality, and sub-nanometer surface homogeneity, all thanks to the special nanoconfined environment. These four major advantages overcome the material limitations and enable us to explore, in the second part of the dissertation, for the first time, the landmark experiments of quantum fluid phase transitions at room temperature: from a normal fluid to both a zero-viscosity superfluid and a Čerenkov supersonic fluid, the unambiguous signatures of Landau criterion in quantum fluids. In addition, the results are in excellent quantitative agreement with our theoretical modeling using nonequilibrium Gross-Pitaevskii equations and the steady-state Bogoliubov excitation spectra analysis. In the third part of the dissertation, we demonstrate, for the first time, XY Hamiltonian graph simulator with the nanoconfined-synthesized crystals at room temperature. We show that lattice with a large number of coherently coupled condensates up to 10×10 can be achieved, which is a significant step towards the ultimate goal of realizing a room-temperature polaritonic platform. In the last chapter, we extend the two-dimensional confined synthesis to surface confinement and study its effect on crystal morphologies.

Advisor: Zhang, Xiang
Translating Touch in Āyurveda: Medicine, Sense, and Subjectivity in Early South Asia and Contemporary Kerala

This textual and ethnographic project engages touch as a hermeneutic to address questions of medical embodiment and expertise as represented in early first-millennium Sanskrit treatises, the Carakasaṃhitā, Bhelasaṃhitā, and Suśrutasaṃhitā, and in contemporary practice in Kerala. Through a study of the Sanskrit category of sparśa in Āyurvedic ontology, and touch more broadly in epistemology, diagnosis, and treatment, I demonstrate that touch establishes physicians’ bodily and social boundaries, is a nexus for the performance of gendered medical expertise, and is central to communication between humans and non-human selves in the practice of leech therapy. The first main intervention of this study is methodological, as I attend closely to the situated expertise of medieval commentators and sensory experience of contemporary practitioners in my reading of the classical treatises. Second, I argue that the early Āyurvedic treatises articulate significant distinctions in practice, expertise, and bodily boundaries for surgeons and for general physicians in the early first millennium. These divergences evidence a greater sensory intimacy and prioritization of trained tactile skill on the part of surgical physicians in this period. Third, through an examination of tactile practices as represented in the classical treatises, this study demonstrates that specific types of trained touch can constitute forms of treatment and explores the ways that gendered expertise is incorporated into the texts. Fourth, I examine the ways that classical epistemologies are navigated by contemporary Āyurvedic physicians in Kerala through sensory negotiation and yukti (reasoning) in a terrain dominated by biomedicine. The final chapters present an ethnography of contemporary Āyurvedic leech therapy and a close reading of the practice as represented in the Suśrutasaṃhitā and Ḍalhaṇa’s Nibandhasaṃgraha. Here, I challenge scholarship that locates medical agency primarily with physicians or patients and propose vascularity as an analytic for interspecies medical practice.

Advisor: Cohen, Lawrence
Goldman, Robert P.
Two-Dimensional Semiconductors for Next-Generation Optoelectronics

With the innovation of technologies that will impact our daily life such as the internet of things (IoT), wearable health care systems, digitally extended reality, and autonomous vehicles, the development of next-generation optoelectronic devices that possess advanced functionality and high performance has emerged as a substantial component for the evolution of future technology. Two-dimensional (2D) semiconductors have been extensively studied in the exploration of new phenomena and properties that are not seen in conventional bulk semiconductors, especially for optoelectronic applications such as light-emitting diodes (LEDs) and photodetectors. While the majority of existing technology relies on bulk crystalline semiconductors, unprecedented possibilities can be opened up for developing next-generation optoelectronics owing to the unique properties and the tuning capabilities that 2D semiconductors offer.Chapter 2 presents the material processing approaches that are applied in atomically-thin semiconductor monolayers to enhance their luminescence efficiency. A combination of optimized doping and growth conditions enables extraordinarily bright luminescence in 2D transition-metal dichalcogenide (TMDC) monolayers with large scale and high stability. Chapter 3 describes the first critical step towards highly efficient LEDs at all brightness using monolayer semiconductors. The fundamental limitations of degraded luminescence efficiency in 2D semiconductors at high photocarrier densities have been identified and overcome by applying small mechanical strain to the materials, leading to the complete suppression of nonradiatvie recombination at all exciton densities. Chapter 4 demonstrates the room-temperature infrared optoelectronic devices whose operating wavelengths can be widely modulated by utilizing strain-tunable bandgap in black phosphorus. Mid-wavelength infrared (MWIR) LEDs with large spectrum tunability are developed and applied in non-dispersive infrared gas sensing technology. Highly-responsive photodetectors exhibit their detectivity exceeding those of state-of-the-art photodetectors with their detection wavelengths spanning from short-wavelength infrared (SWIR) to MWIR range.

Advisor: Javey, Ali
Substrate-borne Bioacoustics and the Impacts of Anthropogenic Noise

Across ecosystems, animals face expanding human populations, transportation networks, and urbanization that threaten their survival. Traditional strategies for conservation often hinge on understanding an animal’s habitat and population structure, with less attention is paid to the animal’s “habit”, their way of being in and sensing the world. However, recent appeals to consider the sensory ecology - the way organisms acquire, process, and share information - of species suggest transitioning away from questions like “What do these organisms eat?” and “Who eats them?” toward questions that ask, “In what ways do these animals find food or avoid being eaten?” For many animals, the ubiquitous answer to questions concerning the mechanism for finding food or mates, avoiding predators, choosing suitable habitats, or communicating with conspecifics is “substrate-borne sound”.Substrate-borne bioacoustics is the subset of bioacoustics that concerns the exchange of information via mechanical waves through substrates such as rock, soil, litter, or plant material. It likely long precedes airborne communication via pressure waves in evolutionary time and is used by the vast majority of terrestrial animals - over 95% of all species. Despite this, substrate-borne bioacoustics have been largely ignored in broad acoustic fields of study. For example, animals sensitive to substrate-borne sounds were long excluded from decades of research attempting to explain the diversity of acoustics across taxa (Chapter 2) and mostly left out of research investigating the impacts of anthropogenic noise on animal behavior (Chapter 3). In this dissertation, my colleagues and I do our best to address these exclusions and examine the impacts of substrate-borne anthropogenic noise on a single species; the mason spider (Castianeira sp.) (Chapters 4 & 5). We found that the exclusion of substrate-borne bioacoustics from major fields of study skewed biophysical explanations of acoustic diversity across taxa and may limit understandings of the reach of anthropogenic noise. In addition, when we narrowed our focus to a single invertebrate species, we found that the impact of substrate-borne anthropogenic noise has profound effects on invertebrate behavior. Our research suggests that understanding substrate-borne bioacoustics and substrate-borne anthropogenic noise may be critically important in conserving species, communities, and ultimately, biodiversity

Advisor: Elias, Damian O
In the (After) Life: Tracing Black Queer Spatialities under Regimes of Displacement, 1963-1989

"In the (After) Life: Tracing Black Queer Spatialities under Regimes of Displacement, 1963- 1989" is a dissertation that explores emotional geographies found within the artistic works of Black Queer cultural producers who witnessed and produced art in a context of Black mass displacement. Informed by the burgeoning field of Black Geographies, "In the (After) Life" comprises chapters that use archival research and narrative inquiry to analyze how madness and abjection constitute the Black Queer urban subject's everyday spatial practice. This dissertation will explore the notes and warnings of Black Queer cultural producers who speak intimately to the process of urban renewal as producing a structured otherness in real space-time. This dissertation will analyze these experiences of abjection from James Baldwin’s Take This Hammer (1963), Pat Parker's Jonestown and Other Madness (1984), and Marlon Riggs' Tongues Untied (1989). Primarily drawing from approaches in Queer of Color Critique, Critical Human Geographies, and Black Studies, "In the (After) Life" explores the term "Archive of Black Queer Spatialities" as a reference for Black Queer subjects creating a spatial response to displacement across multiple waves of urban restructuring in San Francisco. This dissertation closely reads the long history of urban renewal and the various forms that have taken place across the 20th century that has produced emotional geographies of abjection. These affective geographies have material consequences that this dissertation explores: neighborhood isolation, premature death, and mass criminalization. Ultimately, "In the (After) Life" provides a socio-spatial approach to reading anti-Blackness in the built environment of San Francisco.

Advisor: Summers, Brandi T
Behavioral Network Economics

Game theoretic models are prevalent in the study of interactions between autonomous agents. Given the pervasive role of humans as agents in networks (e.g. social networks) and markets (e.g. labor markets), building mechanisms based on presumably more accurate models of human behavior is of great interest both for increasing human welfare and for building more efficient commercial systems that interact with humans. Cumulative prospect theory (CPT), one of the leading models for decision-making under risk and uncertainty, introduced by Kahneman and Tversky, combines several psychological insights into decision theory. Theoretical economics has primarily focused on expected utility theory (EUT) to model human behavior. On the other hand, CPT has been observed to be a better fit in empirical studies, it is a generalization of EUT, and has a nice mathematical formulation convenient for theoretical studies. It provides a way to incorporate psychological aspects into the concrete frameworks of game theory and economics which is required in building large scale systems that are better aligned with human preferences and needs and are also robust to their emotional traits. A systematic and principled approach is needed. This thesis aims to build work in this direction by studying the following three problems through the lens of CPT:1. resource allocation over networks, 2. notions of equilibrium in non-cooperative games, and 3. mechanism design. In this thesis, we develop theoretical tools and establish fundamental results that would support real-world applications and future research in behavioral network economics.

Advisor: Anantharam, Venkat
Pseudospectra of matrices and Point spectra of infinite graphs

In this thesis we look at various tools to analyse eigenvalues and eigenvectors and use themto prove the following main results. 1. We show that given any matrix A, there is a small perturbation of the matrix such that post perturbation, the matrix is almost normal. In particular there exists E, with ||E|| ≤ δ||A|| such that A + E is diagonalizable and its eigenvector matrix has polynomially (in 1/δ and n) bounded condition number. 2. We prove a necessary and sufficient condition for any local periodic operator on the universal cover of a finite graph to have a point spectrum. In particular we show that for λ to be in the point spectrum, the base graph must admit an induced forest with a very specific combinatorial structure and that the induced operator on it must also have λ as an eigenvalue. To prove the first result we study the volume of the pseudospectrum with the help of some tools from stochastic calculus. Along the way we also see why it implies a conjecture by Sankar, Spielman and Teng on the optimal constant for smoothed analysis of condition numbers. For the second result we show that a condition conjectured by Aomoto to be necessary and sufficient for the existence of point spectrum of certain operators on periodic trees is indeed so. Aomoto had already shown why the condition was necessary. We give a more intuitive proof of it and along the way also show sufficiency.

Advisor: Srivastava, Nikhil
Pitman, James W.
Generator-Based Design of Custom Systems-on-Chip for Numerical Data Analysis

With the end of Dennard scaling and the subsequent demise of Moore's Law, the continuous demand for higher computing performance and efficiency is increasingly met through specialization of digital processors. In particular, numerical data processing and machine-learning applications incur high computational costs but often have common computational structures, acting as prime targets for hardware customization. Specialization of digital designs is accompanied by substantial non-recurring engineering (NRE) costs, which limit the proliferation of customized designs. This work presents tools and methodologies for the development of custom systems-on-chip (SoCs) for numerical data analysis applications. An integrated generator-based framework for SoC development is demonstrated through SoC customization and hardware/software co-design for numerical data analysis and machine-learning applications. The development of full-system support from hardware accelerators through system software leads to the identification of several co-design opportunities for increasing accelerator utility in custom SoCs. Specifically, we demonstrate the development of high-performance custom software library implementations to support accelerated numerical data analysis on custom SoCs developed using the Chipyard integrated generator-based framework for custom SoC design. We further identify a need to provide support for processing of a high variety of matrix shapes and sizes in SoC deep learning accelerator matrix engines for accelerated processing of numerical data analysis workloads, and demonstrate up to a 1.25x improvement in the utilization of a matrix engine on small and rectangular matrices through hardware-managed static scheduling, dynamic scheduling, and hardware-managed commutative micro-threading.

Advisor: Nikolić, Borivoje
Asanović, Krste
Explaining Water's Surface

The surface of liquid water is characterized by large fluctuations that are too complex to describe exactly but, like with other aspects of molecular liquids, can be described in a useful way when approached statistically. The water liquid/vapor interface is composed of a sharp drop in density and reverberations from that drop that extend about 1 nm from the surface. Transient but characteristic structure forms as water molecules realign to maximize hydrogen bonding without ready neighbors in vapor. Much of the structure of water’s surface can be accounted for as a broadening of the bilayer structure of the basal plane of the ice crystal, particularly the layering in density and the orientational trends.The mean field surface model predicts the average orientational behavior of structured molecular liquids, which is demonstrated in two dimensions with the water-like Mercedes-Benz (MB) model and in three dimensions with comparisons to the SPC/E and TIP5P models of water. Liquids with strong directional bonding tend to orient predictably when potential bonding neighbors are removed. The mean field surface model assumes that bonds are most likely to form in regions of high density, then uses a self-referencing iterative approach to determine whether neighbors are also likely to be oriented in a way that is favorable to bonding. Physically motivated changes to the reference density, bonding rules, and molecular structure clarify which aspects of molecular water are actually essential to the orientational structure at the interface. It is shown that moderate changes to bonding rules, like flexibility, strength, and asymmetry, have little impact on the main surface patterns. The layering in the density profile of water is by contrast necessary to accurately predict water’s surface structure. All of these observations can be rationalized through liquid water’s relationship to the structure of the basal plane of ice. The dielectric response of water is also affected by the introduction of an interface. The Gaussian field model known as dielectric continuum theory[1–3] (DCT) makes predictions for the effect of an interface on the dielectric behavior of water. Using the method of images[4] and correcting for the dielectric saturation of a rigid water model, it is shown that polarization fluctuations near the air-water interface largely follow these predictions at scales as small as 5 ̊A despite the macroscopic character of DCT.

Advisor: Geissler, Phillip
Certainty and the Source of Misinformed Beliefs

Humans possess a metacognitive sense of certainty which, for better or worse, influences behavior. This sense of certainty is often misleading and can leave us vulnerable to believing false information. In this dissertation, I study how humans form their sense of certainty and the types of false beliefs which we can be at times, highly certain of. This work spans across multiple domains, including concept learning, word-meaning, pseudoscience, and people’s metacognitive beliefs. Across seven experiments, I present empirical evidence that learners use heuristics over idealized model-based features when forming their sense of certainty, and that this leaves us prone to errors which can result in the adoption of misinformed beliefs as drastic as the belief that the Earth is flat.

Advisor: Piantadosi, Steven T
Influence of Defects’ Mechanical Stability on Microscale Plasticity and Failure

Structural materials in nuclear applications are subjected to extreme environments including radiation flux, stress, corrosion, and temperature. These environments can induce brittle failures by changing the material microstructures through either introducing new defects or modifying the pre-existing defects. In this thesis, the role of defects’ mechanical stability on the two primary causes of brittle failures, being strain localization and intergranular cracking are studied. A wide range of defect types from 0D to 3D defects – including interstitial atoms, radiation-induced loops, long-range ordered precipitates, voids, and interfaces – are considered. Additionally, the effects of radiation damage on various pre-existing defects in structural materials are studied. The second aspect of the thesis is to expand the capability of in situ SEM small-scale mechanical testing for a wide range of testing geometries and material conditions. Single-crystal microcompression and microtension are developed to assess the plastic deformation of individual grains as a function of defect types. Furthermore, novel bicrystal testing of grain boundaries are developed to measure the grain boundary strength of oxidized and irradiated materials. The key findings of the thesis reveal that the mechanical stability of the defects strongly influence strain localization, slip formation, and microscale plasticity. Furthermore, the stability of intragranular defects reduce the intergranular cracking susceptibility by inhibiting strain localization.

Advisor: Hosemann, Peter
The Stereoselective Formation and Cleavage of C–F Bonds via Group 11 Catalysis

Chapter 1 – The gold(I)-catalyzed, stereoselective hydrofluorination of electron-deficient alkynes with triethylamine trihydrogen fluoride (Et3N·3HF) is described. Fluorinated α,β-unsaturated aldehydes, amides, esters, ketones, and nitriles were isolated in moderate to good yields as single diastereomers. In all but four cases, the (Z)-vinyl fluorides were initially formed in ≥97% diastereoselectivity. This work constitutes the first catalytic example of the diastereoselective preparation of a variety of β-alkyl, β-fluoro Michael acceptors from alkynes. Additionally, the described work expands access to β-aryl, β-fluoro Michael acceptors to the synthesis of β-fluoro- α,β-unsaturated amides and nitriles. The monofluoroalkenes formed through this strategy were readily transformed into other fluorine-containing compounds, and the developed method was applied to the synthesis of a fluorinated analogue of Exoderil, a topical antimycotic./nChapter 2 – The copper-catalyzed silylation of propargylic difluorides to generate axially chiral, tetrasubstituted, monofluoroallenes in both good yields (24 examples >80%) and enantioselectivities (82–98% ee). Compared to previously reported synthetic routes to axially chiral allenes (ACAs) from prochiral substrates, a mechanistically distinct reaction has been developed: the enantiodiscrimination between enantiotopic fluorides to set an axial stereocenter. DFT calculations and vibrational circular dichroism (VCD) suggest that β-fluoride elimination from an alkenyl copper intermediate likely proceeds through a syn-β-fluoride elimination pathway rather than an anti- elimination pathway. The effects of the C1-symmetric Josiphos-derived ligand on reactivity and enantioselectivity were investigated. Not only does this report showcase that alkenyl copper species—like their alkyl counterparts— can undergo β-fluoride elimination, but that this elimination can be achieved in an enantioselective fashion. The resulting monofluoroallenes were shown to undergo a copper-catalyzed desilylative acylation. A kinetic resolution was developed, generating propargyl fluorine-containing quaternary stereocenters. Current efforts are underway to better understand the system that aim to achieve dynamic kinetic resolution.

Advisor: Toste, Dean F