VictorJuiz/thesis huggingface dataset:
Heuristics and bounds for photonic design

This thesis covers a number of results in heuristics for approximately solving photonic design problems and bounds for the optimal value of such problems. Chapter 2 begins the thesis with an overview of the literature and a very general introduction to the photonic design problem, along with simplified summaries of the usual techniques used in both approximately solving physical design problems and in computing bounds for the optimal value of these optimization problems. Chapter 3 shows a heuristic which can be used to find approximate solutions to the photonic design problem and discusses some interesting observations based on the ideas introduced. In chapter 4, we cover a particular technique for bounding the optimal value of photonic design problems, along with several generalizations. Finally, chapter 5 shows a generalization of a number of bounds available in the literature to include objectives that often show up in efficiency metrics

Keywords: Electrical Engineering.
Advisor: Boyd Stephen P. 
Fan Jonathan Albert
Miller D. A. B.
Vuckovic Jelena
Higgs pair production searches with the ATLAS experiment at the LHC and the HL-LHC

Exploring the Higgs potential and electroweak symmetry breaking is one of the main goals at the Large Hadron Collider (LHC). Higgs pair production (HH) provides experimental access to the shape of Higgs potential and is the only direct probe of the Higgs self-coupling in proton-proton collisions. This thesis presents a search for HH production in the bbyy channel with the ATLAS experiment at the LHC with 139/fb of data at 13 TeV. The results from this search are combined with results from the bbtautau and bbbb channels to produce the most stringent limits on Standard Model HH production and the Higgs self-coupling to date. In addition to the present results, this thesis discuss ways to improve sensitivity to HH production during Run 3 and our projected sensitivity to HH production at the High Luminosity-LHC with 4000/fb at 14 TeV. The ATLAS Inner Tracker detector upgrade which is required to enable these searches is also presented

Keywords: Physics.
Advisor: Su Dong (Computer scientist)
Vernieri Caterina 
Gratta Giorgio
Nelson Timothy Knight 
Toro Natalia
High pressure deformation of nanostructures and lightweight alloys

Lightweight and strong alloys can reduce fuel consumption in vehicles, aircrafts and ships, and reduce spacecrafts and satellites payloads for deep space exploration. Low-density Al and Mg alloys that derive their high strength and mechanical properties from the collective interaction of defects with nanoscale precipitates are of interest for these applications. Individual nanoscale structures have also shown exceptional mechanical properties like high strength and elasticity. Nanostructuring of bulk alloys can be an effective strategy to reduce the density of the components and improve their strength. This bottom-up fabrication strategy requires a comprehensive understanding of deformation mechanisms at the nanoscale which is difficult to obtain. In situ electron microscope measurements on individual nanoparticles have shown unique deformation behaviors governed by the surface of the nanoparticles. These in situ measurements fall short in capturing the complete defect activity under stress, and suffer from limited measurement statistics and inadvertent heating of the nanoparticles. Diamond anvil cell (DAC) is a tool consisting of two diamond anvils opposing each other with the sample between them. The DAC setup applies a static high pressure on the sample through a pressure transmitting medium and allow in situ characterization of materials using optical and X-ray methods. Using this method I test and understand the deformation behavior of an ensemble of nanoparticles and nano-precipitates in bulk alloys under extreme conditions

Keywords: Materials Science and Engineering.
Advisor: Dauskardt R. H. (Reinhold H.)
Gu Wendy (Professor of mechanical engineering)
Dionne Jennifer Anne
High Throughout Genome Editing in Human Embryonic Stem Cell-Derived Neurons

Studying the localization and abundance of neuronal proteins provides valuable insights into their physiological significance and interactions. Labeling of synaptic proteins has been traditionally achieved by immunohistochemistry or viral overexpression of fusion proteins, but these approaches have several limitations. The molecular architecture of synapses comprises hundreds of pre- and post-synaptic molecules, yet only a small fraction of these molecules can be reliably visualized due to the limited availability of specific, high-affinity antibodies. Moreover, immunohistochemistry and overexpression can introduce artifacts and inaccurately recapitulate the distribution of proteins in live cells. Mapping the synaptic proteome with precision and without being encumbered by the availability of quality antibodies, necessitates the use of genetically encoded fluorescent reporters that can be used to tag any molecule of interest. To meet this need, we designed and optimized a CRISPR-HDR strategy to visualize the endogenous expression patterns of neuronal proteins while leaving a minimal genetic footprint. Given the low HDR efficiency in post-mitotic cells like neurons, we leveraged our ability to edit human embryonic stem cells (hESCs) efficiently and induce them into mature, glutamatergic human neurons (iN). Using our approach, we successfully knocked in a HaloTag at the RIMS1 locus in hESCs, isolated pure RIMS1 knock-in cells using a relatively scarless selection strategy, and subsequently differentiated them into iN. We then validated the functionality and correct localization of the HaloTag by microscopy, establishing RIMS1:HaloTag as a reliable presynaptic marker in iN. To demonstrate the generalizability of our approach and the feasibility of a knock-in screen for synaptic molecules, we proceeded to tag other neuronal proteins like FZD3 and DLG4.

Keywords: synapse
CRISPR (Genetics)
Neurons
super resolution imaging
Text
Thesis
Advisor: Südhof Thomas
High voltage electrode development and the LZ experiment's WIMP search

Approximately 15% of the matter density in the universe is composed of Standard Model particles, while the other 85% is composed of an enigmatic "dark" matter whose fundamental properties are unknown. In recent decades, there has been substantial interest in performing a direct detection of scattering between dark matter and Standard Model particles, but currently no such signature has been verifiably observed. The LUX-ZEPLIN experiment was built to perform such a direct detection of dark matter using a dual-phase xenon time projection chamber (TPC), which can observe both light and charge signals from an interaction in the xenon. The dual-phase xenon TPC technology is critically dependent on maintaining strong drift and extraction fields in order to observe the charge signal. These fields are established by a set of four stainless steel wire mesh high voltage electrode grids that span the full width of the TPC. During operation, these grids achieve wire surface fields well above 15 kV/cm. These high fields can produce spurious charge signals and signals from real radioactive decays with atypical light-to-charge ratios, both of which can lead to low-energy backgrounds in LZ science data. As a result, substantial effort in the design, construction, validation, and operation of these grids was required to ensure that the LZ detector could be used to pursue world-leading dark matter searches. This work presents a detailed characterization of these efforts, from grid design all the way through first science run data with LZ. This work also presents two analyses performed within the first six months of datataking: the first science run searching for WIMP dark matter, and an analysis of radiogenic backgrounds from the high voltage grids. While the former analysis represents an immediate world-leading sensitivity to WIMP dark matter between about 10 GeV/c^2 and 10 TeV/c^2, the latter analysis lays a new foundation for the background model needed to search for dark matter at much lower masses, down to approximately 1 GeV/c^2

Keywords: Physics.
Advisor: Shutt Thomas (Thomas Alan)
Akerib Daniel S.
Burchat P. (Patricia)
Friedland Alexander
High-dimensional problems in probability, optimization, and learning

This thesis concerns several problems in probability, optimization, and machine learning. In the first part we study mixing and sampling. We first revisit the riffle shuffle, generalizing the classic ``seven shuffles suffice'' result of Bayer and Diaconis to shuffles with asymmetric cuts. We then study our first spin glass model, aiming to sample from the Sherrington-Kirkpatrick Gibbs measure in the high-temperature phase. We develop a new approach based not on a Markov Chain, but instead on Eldan's stochastic localization. Moreover we prove a hardness result for stable algorithms using Chatterjee's disorder chaos. In the second part we turn to optimization, aiming to find approximate ground states in spin glass models. This problem is intimately related to their low temperature behavior, and the limiting ground state energy is given by the Parisi formula at zero temperature. We determine an exact algorithmic threshold for a natural class of stable algorithms, which is achieved by approximate message passing algorithms. Our hardness results stem from a refined landscape property that we christen the branching overlap gap property. The third part concerns two problems in high-dimensional machine learning. We first study the problem of chasing convex bodies, in which one aims to perform stable convex optimization to obtain robust performance guarantees in changing environments. The solution involves a generalization of the classical Steiner point in convex geometry and its connections to Lipschitz selection. Finally we establish the law of robustness, showing that a natural robustness memorization task in high dimension requires extremely overparametrized machine learning models to solve

Keywords: Mathematics.
Advisor: Bubeck Sébastien
Montanari Andrea
Diaconis Persi
High-precision acoustic and inertial sensors in interferometric silicon micro-structures

In recent years, fiber-based optical sensors utilizing a flexible diaphragm microstructure as a mechanical transducer have surpassed conventional electronic MEMS sensors as compact, high-resolution force sensors. They have been implemented as acoustic sensors and accelerometers capable of resolving µPa/√Hz and µg/√Hz over tens of kHz of bandwidth, enabling a wide range of high-performance applications such as long-range inertial navigation, underwater communications, and cellular studies. In particular, state-of-the-art optical MEMS acoustic and acceleration sensors, typically based on Fabry-Perot or phase-front modulation (PFM) interferometers, exhibit a particularly high sensitivity. However, these sensors are difficult to align during assembly, and they have a strong wavelength dependence, which makes it challenging to multiplex them into arrays. They also require active feedback of the wavelength of the laser used to probe them in order to maintain a stable, high sensitivity. This thesis presents the theoretical modeling and experimental characterization of two new generations of PFM sensors that address these issues by self-aligning a fiber with a diaphragm suspended on micrometric springs to form a stable two-wave interferometer. Fabricated on silicon-on-insulator wafers using standard clean-room tools, these sensors are compact and quick to assemble reproducibly, and they exhibit a weak wavelength dependence and no polarization dependence. The first generation of hydrophone has a flat sensitivity extending from 100 Hz to 2 kHz and an average minimum detectable pressure over this region of 74 µPa/√Hz. With a resolution comparable to the noise of quiet ocean environments, these sensors are good contenders for deep-ocean acoustics and seismic monitoring. The second generation of sensors implements a novel self-aligning scheme and demonstrates a reproducible sensitivity spectrum. They exhibit a record low resolution of 215 nPa/√Hz between 40 Hz and 3 kHz, which represents a 10-fold improvement over the previous record reported in the literature. With an equivalent force resolution of 1.5 pN/√Hz, these new sensors are well-positioned for micro-cellular studies. They are in fact sensitive enough to resolve the extremely weak phase noise imparted to the probe light by the thermal noise of the diaphragm structure. When used as accelerometers in a vacuum, their resolution is as low as 160 ng/√Hz over 3 kHz of bandwidth, which satisfies the most stringent requirements for inertial navigation of aircraft

Keywords: Electrical Engineering.
Advisor: Digonnet Michel J. F.
Soh H. Tom
Vuckovic Jelena
High-speed D/A conversion in FinFET CMOS technology

Digital-to-analog converters (DACs) are crucial building blocks in modern communication systems like wireline transceivers and digital mm-wave phased arrays. These applications drive steady increases in bandwidth, channel count, as well as integration density, which mandates data converters that are compatible with the latest CMOS technology. For analog-to-digital converters (ADCs), this has led to an architectural shift toward time-interleaved successive approximation, which exploits the strengths of modern CMOS while mitigating its weaknesses. On the other hand, DACs have not significantly changed since the 1970s and predominantly rely on the current steering (CS) topology. We discuss an alternative approach for high-speed (> 10 GS/s), moderate-resolution (6-8 bit) DACs, with the specific goals of reducing chip area and improving FinFET CMOS compatibility. Our DAC uses a switched capacitor (SC) architecture that separates the functions of level generation, timing/combining, and output power delivery, which are lumped into a single node in a conventional CS DAC. In the proposed DAC, levels are generated using time-interleaved SC DAC cores with sub-femtofarad unit capacitors, which offer sufficient linearity and noise performance at the 8-bit target resolution. The cores' outputs are combined and re-timed downstream and the final 50 Ohm load is driven by an inverter-based buffer. To validate this new approach, we implemented a series of 8-bit prototype DACs in 16 nm FinFET CMOS, operating at 14 GS/s, 28 GS/s (2x time-interleaved) and 56 GS/s (4x delta-interleaved), respectively. These designs show competitive performance while achieving up to 10x area advantage over the state of the art

Keywords: Electrical Engineering.
Advisor: Murmann Boris
Arbabian Amin
Horowitz Mark (Mark Alan)
The historical origins of Republican economic ideology : a computational text analysis approach

This dissertation seeks to understand the historical origins of modern Republican economic ideology. I contribute to this topic by using computational text analysis methods to quantitatively characterize ideological language from the past and track its persistence into modern political speech. The first chapter tracks the persistence of segregationist language from the mid-20th Century in economic speeches today. The second paper focuses on the persistence of conservative and liberal language from the New Deal era. Finally, the third paper focuses on the specific issue of immigration and compares attitudes of politicians in the past vs. the present. I contribute to the economic history literature by more comprehensively quantitatively linking language from the past and present using innovative natural language processing methods and interpreting these findings within the broader historical context

Keywords: Economics.
Advisor: Abramitzky Ran
Hall Andrew B.
Wright Gavin
History and reality : on narratives of suffering and reconciliation

History and Reality: On Narratives of Suffering and Reconciliation is a literary-philosophical dissertation about literary representations of worldly suffering. Specifically, the texts studied in this dissertation belong to a genre of literature which we could call reconciliatory. Though suffering constitutes the general theme of these texts, these reconciliatory narratives are neither optimistic (in the sense of Leibnizian theodicy) nor pessimistic (in the sense of Schopenhauerian negativity). Rather, they reject philosophical pessimism's conclusion that life is not worth living, not by disputing the reality of historical suffering nor by justifying it in the context of metaphysical ideas of the good, but by insisting on the possibility of reconciliation with such an existence. In a series of highly philosophical readings of Jerzy Kosinski's The Painted Bird, Hanya Yanagihara's A Little Life, and Ta-Nehisi Coates's Between the World and Me, I argue that reconciliatory narratives such as these imagine an alternative response to the existential a priori of human suffering, one that not only charts a third path beyond the tired dualisms of moral philosophy, but that also challenges the moral philosophical assumption that the validity of something like existence could ever be conditional on ethical abstraction

Advisor: Saldívar Ramón
Greif Mark
Moya Paula M. L.
Holographic Quantum Error Correction from half-line-AdS/BCFT

The AdS/BCFT correspondence is a novel setting in which to study the holographic principle, which has not yet been studied as thoroughly as the regular AdS/CFT correspondence. In particular, it replaces the familiar CFT with one defined on a manifold with a boundary. In this report, we show analogous results on the boundary-bulk operator correspondence as in AdS/CFT, as well as present a tensor network model for the new formulation. In this process, we extend the HKLL construction to AdS/BCFT under particular constraints - namely, states obtained from $\Z_2$ symmetry. We also provide a simulation of the percentage of qubits necessary for recovery of information on the bulk. We then point to future studies implementing this model.

Keywords:  Department of Physics
quantum error correction
AdS/CFT
Text
Thesis
Advisor: Hayden Patrick
Qi Xiaoliang
How Americans think about democracy

This dissertation examines how Americans think about democracy, and how presidents can shift what they deem allowable in a democracy. The first paper explores how people talk about democracy and finds that respondents mention rights and freedoms the most in their open-ended responses. Additionally, there are divisions in how people think about democracy along a variety of demographic lines, most notably by partyID: Democrats mention voting and equality more, and Republicans mention the Constitution and what should be fixed in the country. The second paper examines heterogeneity in beliefs around democracy by asking respondents about six precise democratic principles. Respondents support the democratic idea on four of the six statements similarly. However, many respondents in both parties support media censorship and allowing politicians to call their opponents disloyal. The third paper leverages two survey experiments to show that voters allow presidents of their own party to push democratic norms more than a president of the opposing party. Combined, both of these experiments show that voters are 'following the (party) leader' and underscore that many voters place partisanship above democratic health

Keywords: Political Science.
Advisor: Moe Terry M.
Grimmer Justin
Jefferson Hakeem
How does better access to public firm disclosures affect IPO firm financing?

I study how improved access to public firm disclosures affects private firm financing through IPOs. Theory indicates that although improved access to public firm disclosures can reduce IPO investors' valuation uncertainty, it can also lead to increased adverse selection. This tension leaves the net effect of public disclosure improvements on IPO pricing uncertain. I exploit the introduction of EDGAR to examine this question empirically. The results show IPO firm underpricing decreases systematically as more public peer firms adopt EDGAR. This finding is stronger when IPO investors face more valuation uncertainty, when peer firms' information quality is high, when alternative information sources are scarce, and when peer disclosures contain more industry-wide information. Increased equity research coverage of public peers also contributes to this finding. Together, the results suggest better dissemination of public firm disclosures can reduce frictions for private firms seeking to procure equity capital

Keywords: Business.
Advisor: Lee Charles M.
Marinovic Iván
Barth Mary E.
Gipper Brandon
Kepler John D.
How Eurosceptic Party Rhetoric is Changing in the Post-Brexit Era

Euroscepticism has been on the rise in Europe for the past two decades and saw its first major political win in the United Kingdom’s decision to leave the European Union in 2016. Scholars feared this “Brexit” referendum would spark a wave of Euroscepticism to wash over the continent and prompt more “leave” referendums, but the drawn out negotiations over a withdrawal deal have dampened much of the European public’s Eurosceptic fervor. How have Eurosceptic parties reacted in the post-Brexit era? In this thesis, I use a combination of Eurosceptic party manifesto data, Eurobarometer survey data, and case studies of specific Eurosceptic parties to assess to what extent the rhetoric of Eurosceptic parties changed in reaction to Brexit, and explore the factors driving these changes. My analysis suggests that hard Eurosceptic rhetoric, which is rhetoric advocating for a member state to leave the EU, dropped slightly in the aftermath of Brexit. This thesis contributes to the literature on Eurosceptic thought, European Union cohesion and empirical studies that use rhetoric as a measure to gauge political party intentions.

Keywords: Euroscepticism
European Politics
Brexit
Manifestos
Text
Thesis
Advisor: Crombez Christophe
Human natural killer cell development in the age of single cell technologies

The study of hematopoiesis has been an ongoing effort to understand how the immune system develops. Throughout the course of history, the use of flow cytometry has enabled us to understand the development of multiple immune cell lineages. However, human Natural Killer (NK) cell development remains an elusive developmental population requiring further study to identify. NK cells have been characterized as cytotoxic innate lymphocytes that produce cytokines and clear viral infected and cancerous cells. Unlike other immune cell lineages, a comprehensive developmental pathway has yet to be identified. While developmental populations have been identified in human bone marrow (BM), these cells are rare and a larger pool of progenitors must exist due to their short lived nature. The use of single cell technologies presents an innovative approach to dissect the BM compartment and find novel precursors that will elucidate the development of NK cells. Utilizing these technologies allowed for the identification of a group of cells identified using transcriptional regulators key to NK cell development, ETS1 and ID2. Ultimately, our study expands our knowledge of new stages of NK lineage commitment for use in cancer immunotherapies

Keywords: Microbiology and Immunology.
Advisor: Bendall Sean
Cleary Michael L.
Krams Sheri Michele 
Majeti Ravindra