UC Berkeley

Quantum locally recoverable codes (QLRCs) have recently gained attention as a framework for achieving efficient quantum storage with local recovery capabilities. Analogous to their classical counterparts, QLRCs allow a lost qudit to be reconstructed using only a small subset of other qudits, thereby reducing the resource and operational overhead in recovery. In this work, we extend the study of QLRCs by considering (r, δ) QLRCs characterized by locality parameter r and local distance δ ≥ 2. We present constructions of both random and explicit (r, δ) QLRCs, including explicit families based on the quantum Tamo—Barg construction. We also present an efficient decoding algorithm for these quantum Tamo–Barg codes.Furthermore, we introduce quantum hierarchical locally recoverable codes (QHLRCs), which extend local recovery to multiple hierarchical levels. For any integer h ≥ 2, we construct both random and explicit h-level QHLRCs—the latter being h-level quantum Tamo—Barg codes—and establish a Singleton-like bound for these codes using a CSS framework built from dual-containing classical codes. These results advance the theoretical foundations of quantum erasure recovery and contribute to the design of efficient quantum storage architectures.

One of the largest obstacles in modern drug discovery is that a significant portion (>90%) of the proteome is considered “undruggable,” in that these proteins lack a characterized, functional binding pocket or ligandable hotspot which small molecules can bind to and modulate the protein’s function for therapeutic benefit. To overcome such disease-causing proteins, targeted protein degradation (TPD) strategies have arisen, where the cell’s endogenous degradation machinery is hijacked to ubiquitinate and degrade the classically undruggable protein. Molecular glue degraders serve as a promising modality to achieve TPD. These are monovalent compounds that induce the proximity of a target protein with a component of the ubiquitin proteasome system to degrade the protein of interest. While our research group has previously identified a fumarate-based electrophilic handle that covalently modifies the E3 ligase RNF126 to enable degradation of multiple protein targets, the high intrinsic reactivity and cytotoxicity of the fumarate handle limited its translational utility. This work describes the development of an optimized and metabolically stabilized RNF126-targeting covalent handle incorporating a trans-cyclobutane linker that exhibits reduced glutathione reactivity and diminished cytotoxicity while retaining robust degradative activity. Using BRD4 as a benchmark target, we demonstrate that this optimized handle yields a potent and selective BRD4 degrader whose activity is dependent on RNF126. We further extend this strategy to the androgen receptor (AR) and its clinically intractable splice variant AR-V7, demonstrating selective degradation of both AR and AR-V7 in androgen-independent prostate cancer cells and robust inhibition of AR transcriptional activity that surpasses the established AR antagonist enzalutamide. Together, this dissertation establishes a generalizable, chemistry-centric framework for converting small-molecule ligands into covalent molecular glue degraders, offering a roadmap for exploiting event-driven pharmacology against the most intractable targets in the human proteome.

This dissertation studies Large Language Model (LLM) inference through the lens of statistical decision-making theory, with the goal of advancing prevailing inference paradigms along two principal axes: scalability and provenance. In the domain of scalability, this dissertation investigates the efficiency of inference-time scaling paradigms and parallel decoding schemes. We formally characterize the sample complexity of self-consistency and best-of-n sampling methodologies, and demonstrate how self-correction can substantially expand the expressive power of Transformer architectures in multi-task settings. We analyze the information-theoretic bottlenecks associated with parallel sampling in diffusion language models, and introduce Explore-Then-Exploit, a scalable decoding strategy that improves inference throughput while preserving generation quality. In the domain of provenance, the dissertation develops theoretical foundations and practical schemes for statistical watermarking. We mathematically formalize statistical watermarking as a hypothesis-testing problem, providing a comprehensive characterization of the optimal Type II error, token efficiency, and robustness against perturbations. Guided by the theoretical insights, we propose SEAL, a semantic-aware watermarking scheme demonstrating strong detection efficiency and tamper resistance. We further generalize the statistical watermarking framework to support anytime-valid detection and derive the optimal e-value-based detection scheme. Collectively, our work connects theoretical insights with algorithmic innovations for understanding and improving the efficiency and responsible use of LLM inference.

The Death of the Asylum: How Federal Policy, Popular Culture, and Drugs Killed the American Mental Hospital (1940-1946) is a historical study of three interwoven elements that led to the end of asylums or psychiatric institutions in mid-20th century America. The dissertation is an interdisciplinary project that brings together methodologies from the history of architecture, psychiatry, and law to tell the story of the extinction of an American institution and building type. The work argues that 1946 was a pivotal year for the beginning of “deinstitutionalization,” defined as the phasing out of institutional treatment of mental illness in asylums established in the late 19th-century and towards an outpatient medical model. This shift fundamentally altered the profession and practice of psychiatry.The first chapter explores the legacy of journalistic exposés and literature starting in the late-19th century by writers who were hospitalized for feigned or real mental illness. These writers, such as Nellie Bly and Mary Jane Ward, used their experience in the asylum to write books and articles that chronicled their often-shocking journeys and critiqued the treatment they received. The chapter begins with a historical overview of the original ideals and humanitarian intentions of the 19th-century asylum. A new architectural typology in the late 1800s, this building type was rooted in the healing power of nature and the built environment. This historical and architectural exposition provides a stark contrast to what became of asylums by the mid-20th century, which the conscientious objectors of Chapter 2 sought to change. The chapter then primarily analyzes Ward’s popular novel The Snake Pit (1946) and its Hollywood film adaptation (1948), and Ward’s courageous but costly involvement in mental health reform. The second chapter begins in 1940 with the Selective Training and Service Act to tell the story of the four conscientious objectors who created the Mental Hygiene Program of the Civilian Public Service during World War II. I argue that these leaders—Leonard Edelstein, Hal Barton, Phil Steer, and Will Hetzel—changed the trajectory of mental health treatment in the United States through their activism. After being assigned to work in understaffed asylums as part of their alternative service because of their pacifist beliefs that protested the war, these conscientious objectors led a movement to document widespread abuses among hundreds of mental hospitals, analyze existing mental health commitment laws, and educate and retrain future employees of mental hospitals.The final chapter follows the career of journalist and wartime correspondent Albert Q. Maisel, who worked with the conscientious objectors in Chapter 2 who had formed the National Mental Health Foundation at the conclusion of World War II. In partnership with the conscientious objectors, Maisel procured eye-witness testimonies and haunting photographs to write a scathing and damning exposé article titled “Bedlam 1946,” which was published in Life Magazine on May 6, 1946. The chapter concludes with the National Mental Health Act (NMHA), which was signed into law by President Harry Truman on July 3, 1946. The Act funded the creation of the National Institute of Mental Illness (NIMH), catalyzed the development of psychopharmacological treatment, and was the final nail in the coffin for the American asylum. Through archival research, this dissertation demonstrates how, in 1946, the dream of the curative mental asylum was over.

Artificial intelligence (AI) is increasingly used by individuals, firms, and organizations around the world, offering an opportunity to expand capabilities and improve livelihoods. Yet adopting and adapting to any new technology is difficult, and these challenges are compounded when the technology is as complex as AI. This dissertation examines how AI could shape strategic decision processes, with a focus on understanding the implications of AI system capabilities for low-resource contexts. Underlying the dissertation is the idea that if we want AI systems to have a positive impact, we must begin by understanding model performance. My first two essays explore this within the context of AI-generated advice: if we can understand where generative AI provides high-quality advice, then we can identify cases where AI should be deployed and cases where additional input may be needed in order to be beneficial to the user. I start by exploring this within the context of a field study in Kenya which varies the extent to which individuals receive advice from an AI system as opposed to traditional human advice. Results from this study suggest that AI-generated advice and expertise may reinforce each other, while highlighting the risks that can emerge if individuals begin to use AI at the expense of vetting the advice they receive by engaging with external sources of information. I then explore the extent to which the recommendations produced by AI systems may inadvertently privilege some contexts over others. Specifically, I test whether the default response from AI systems provides higher quality advice to individuals living in high- versus low-resource contexts. Results from this study provide evidence that default responses from AI are more aligned with high-resource contexts, which I document both within and across countries. However, I find that much of the difference in the quality of responses provided by AI stems not from fundamental differences in the model's underlying capabilities, but instead from the default context assumed by the model. Finally, I examine the performance of AI in the context of a specific use case, evaluation. I develop a test of whether AI systems prefer proposals that were written by AI through a novel design which holds proposal quality constant, varying only the extent to which language inordinately used by AI models is included in the proposal. I provide evidence of self-preference in model evaluation, and show that these distortions are substantial enough to change the ranking of proposals, while also highlighting that because of the low cost of using AI for evaluation, it can still be beneficial to use AI systems, even given these errors, if the alternative evaluation strategies are sufficiently costly. Together, these essays highlight the potential of generative AI systems to improve people's livelihoods, while also cautioning that understanding the capabilities of these systems is fundamental to using them effectively. By better understanding AI system capabilities, we can identify when more contextual information or guidance is needed, and when AI advice, while imperfect, may still be efficient due to its lower cost. As the capabilities of AI systems continue to rapidly improve, ensuring that these tools are deployed with the right enabling resources will be an important part of realizing their potential for people around the world.

The works investigate reliability and performance enhancement for ultra-scaled advanced CMOS and memory devices through experimental characterization, physical modeling, and device simulation. The study first examines random telegraph noise (RTN) in advanced transistors under cryogenic operation, revealing the strong dependence of carrier trapping dynamics on temperature and bias conditions. A physics-based RTN modeling framework, combined with experimental results, is developed to predict RTN behavior in nanoscale transistors. In addition, the impact of ultra-thin aluminum incorporation within high-k metal gate stacks (HfO₂/TiN) is investigated. Electrical characterization and material analyses reveal that aluminum modifies the effective work function through oxygen scavenging from the TiON layer. The reliability trade-offs associated with Al incorporation in the metal gate are further clarified. Next, to mitigate the side effects of Al-incorporated gates, an oxygen insertion (OI) technology is proposed as an alternative approach for controlling the flat-band voltage. Lastly, a silicon-germanium/silicon (SiGe/Si) heterojunction drain transistor is proposed for 3D NAND flash memory to enhance gate-induced drain leakage (GIDL) and improve erase speed through increased band-to-band tunneling. Simulation results demonstrate significant improvement in erase performance without degrading inhibit-mode operation.

Arctic Modernity: Welfare Colonial Architecture in Kalaallit Nunaat (Greenland) examines the built environment of the Danish-led modernization of Greenlandic cities from 1953 to 1979. During these years, the Danish state sought to rapidly modernize, industrialize, and Danify Greenland, transforming the former colony and its Indigenous Inuit population into an Arctic part of the emerging postwar Danish welfare state. Taking my analytical starting point in the South Greenlandic town of Paamiut, I analyze multiple scales of the city’s built environment to trace how large-scale rural-to-urban displacements, high-modernist mass housing, coercive domestic environments, and racialized systems of labor and materiality reveal architecture’s role in the attempted transformation of Greenland and Inuit. Challenging existing historical narratives and conventional methodological approaches to research on Scandinavian modernism, colonial history, and the Greenlandic-Danish relation, I foreground the Indigenous Inuit experience of these transformative years. I do this by building an eclectic methodological approach that combines oral histories, archival research, critical cartography, material history, and visual culture, while drawing on a wide range of sources. Inspired by contemporary decolonial scholarship and the field of Critical Arctic Studies, I highlight Indigenous agency within spaces and systems of coercion, demonstrating how inhabitants adapted and subverted the imposed welfare modernism. Extending into the present, I show how local communities are now building alternative futures from the rubble of these failed urban experiments. Through my historical analysis, I show how the Danish government merged welfare and colonialism by using modern architecture, urban planning, and welfare ideology as colonial tools to retain Greenland’s territory and shape cultural relations of the North Atlantic and Arctic. By suggesting that Greenland was never peripheral but, in fact, central to the development of Danish modernism and postwar welfare ideology, the dissertation contributes to decolonial scholarship on welfare-state architecture, illuminating how legacies of welfare colonialism continue to impact Greenland, the Danish Realm, and the broader Global High North.

Viazovska resolved the 8-dimensional sphere packing problem by constructing the magic function for the Cohn–Elkies linear programming bound, proving that the E8 lattice packing is the densest possible packing. Soon after, Cohn, Kumar, Miller, Radchenko, and Viazovska gave a similar proof for the 24-dimensional case, showing that the Leech lattice gives the densest possible packing. One of the main steps of the proof is to verify nonpositivity and nonnegativity of the functions and their Fourier transforms, which reduces to inequalities for certain quasimodular forms. The original proofs by Viazovska and by Cohn et al. are based on interval arithmetic and Sturm’s bound, which are numerical in nature. Later, Romik gave an alternative proof of the inequalities in dimension 8.In this thesis, we give new algebraic proofs of the inequalities for both dimensions 8 and 24. In particular, we develop a theory of positive and completely positive quasimodular forms, and study how positivity interacts with derivatives and Serre derivatives of quasimodular forms. This theory is simple but powerful enough to give short proofs of the quasimodular form inequalities. We also find that the corresponding quasimodular forms are closely related to the extremal quasimodular forms by Kaneko and Koike. Along the way, we also prove that the depth 1 extremal quasimodular forms are completely positive, i.e. all the Fourier coefficients are positive, which resolves Kaneko and Koike’s conjecture in this case. The application of the theory of positive quasimodular forms is not limited to the sphere packing problem. We also study the monotonicity of functions of the form 𝑡 𝑚𝐹(𝑖𝑡) for a quasimodular form 𝐹 and 𝑡 > 0, which gives a new proof of one of the inequalities in Cohn et al.’s work on the universal optimality of E8 and the Leech lattice, and also provides a way to construct positive quasimodular forms of higher levels. We also study higher-level analogues of extremal quasimodular forms by Sakai and Tsutsumi, focusing on the positivity and integrality of their Fourier coefficients in the case of depth 1 and level Γ0(𝑁) when 𝑁 = 2, 3, 4, and also depth 2 and level Γ0(2).Finally, we give new lower and upper bounds for Bourgain, Clozel, and Kahane’s sign uncertainty principle in certain dimensions that are multiples of 4. For the upper bounds, we prove that the Fourier eigenfunctions constructed by Feigenbaum, Grabner, and Hardin are nonnegative, which gives improved upper bounds for A+(𝑑) for dimensions 𝑑 ≤ 36000. For the lower bounds, we follow Cohn and Gonçalves’ approach and use summation formulas for radial Schwartz functions associated with extremal Eisenstein series, giving improved lower bounds for A(−1) 𝑑/4+1 (𝑑) for 𝑑 ≤ 10000.

This dissertation comprises three essays examining how the distinctive features of developing economies shape the decisions of firms and households. The unifying argument is that economic findings from high-income settings often fail to transfer cleanly to low- and middle-income countries (LMICs), where incomplete markets, weaker infrastructure, limited social protection, and severe budget constraints fundamentally alter the problems that agents face. Ignoring these differences may harm both academic understanding of low-income economies and the effectiveness of economic development policies. The first chapter asks whether risk aversion prevents firms in developing countries from pursuing profitable but uncertain investments. Standard economic theory assumes firms are risk neutral. This assumption may be correct in wealthy economies where owners hold diversified portfolios. In LMICs, however, most firms are owner-operated, and losses threaten household consumption directly. Using two field experiments with over 1,200 retailers in Kenya, I find that risk aversion significantly impedes the diffusion of new motorcycle helmets, harming retailers, upstream manufacturers, and consumers. These results challenge the assumption of firm risk neutrality and have broad implications for understanding innovation and growth in developing economies. The second chapter introduces a new method for estimating the value of a statistical life (VSL) -- a measure of consumers' willingness to pay for mortality risk reduction that is central to cost-benefit analyses of public policy. By experimentally updating beliefs about risk exposure without altering actual risk, I obtain a precise VSL estimate that is orders of magnitude below values from high-income settings. I argue this is theoretically consistent: as wealth declines, money's marginal value rises nonlinearly, sharply increasing the opportunity cost of investing in safety. This finding suggests that VSL estimates commonly applied in LMIC policy contexts -- typically rescaled from high-income benchmarks -- may systematically misallocate resources. The third chapter, co-authored with Michael Walker, Nick Shankar, Edward Miguel, and Dennis Egger, examines the effects of large, one-time unconditional cash transfers on infant and child mortality in Kenya. While a substantial literature documents the consumption effects of such programs, their inter-generational and health impacts remain understudied. We estimate that the transfers reduced mortality among children under five by 45\%. Increases in hospital deliveries and reductions in physically demanding labor among pregnant women emerge as key mechanisms. Mortality reductions are concentrated among the poorest households, underscoring how binding budget constraints shape health outcomes at the earliest stages of life.

Rechargeable batteries are a foundational technology for modern energy storage, enabling applications ranging from portable electronics to electric vehicles and grid-scale storage. The accelerating push toward electrification and global decarbonization has intensified the demand for battery systems with higher energy density, improved safety, and long-term reliability. These requirements have motivated growing interest in battery technologies that move beyond conventional liquid-electrolyte lithium-ion systems.All-solid-state batteries have emerged as a leading candidate to address these challenges by replacing flammable liquid electrolytes with inorganic solid-state ion conductors. This architecture offers the potential for enhanced safety and compatibility with high-energy-density electrodes, including high-voltage cathodes and metal anodes. However, the performance and viability of all-solid-state batteries critically depend on the properties of the solid-state electrolyte, particularly its ionic conductivity, electrochemical stability, mechanical ductility, and interfacial stability. Within this landscape, halide-based solid-state electrolytes have recently attracted significant attention as a promising materials class. Compared with conventional oxide and sulfide conductors, halide electrolytes combine high ionic conductivity with wide electrochemical stability windows and favorable mechanical deformability, making them well suited for solid-state battery applications. Understanding and controlling ion transport in halide frameworks is therefore a key scientific challenge for enabling advanced solid-state batteries across both lithium and multivalent chemistries. In lithium-based systems, halide electrolytes are particularly attractive due to their high oxidative stability, enabling compatibility with high-voltage cathodes. Nevertheless, practical deployment remains constrained by the reliance on rare or expensive elements such as Y, Sc, and In, as well as by an incomplete understanding of how disorder and local structural environments govern lithium ion transport. In parallel, rechargeable batteries based on multivalent ions such as Mg2+ offer the potential to surpass the cost and volumetric energy density limitations of Li-ion batteries. Yet, strong electrostatic interactions between multivalent ions and the host lattice severely impede ionic mobility, making the development of fast solid-state Mg2+ inorganic conductors a major scientific and technological challenge. This thesis focuses on elucidating solid-state ion transport mechanisms in halide electrolytes for both Li+ and Mg2+ batteries, with particular emphasis on how metastable structural features, cation ordering, and anion chemistry govern ionic conductivity. By integrating mechanochemical synthesis, advanced structural characterization, electrochemical measurements, and first-principles modeling, this work establishes design principles for enabling fast ion conduction in halide lattices across diverse structural frameworks, including both amorphous and crystalline systems. For Mg-ion transport, this thesis reports the discovery of mechanically soft magnesium gallium halide electrolytes exhibiting room-temperature Mg-ion conductivities of 0.47 mS cm⁻¹, surpassing most inorganic Mg-ion solid conductors. Synthesized via high-energy ball milling, these materials display clay-like deformability that promotes intimate interfacial contact during electrochemical cycling. Detailed analysis reveals that partial anion exchange induced by mechanochemical processing creates undercoordinated magnesium environments within chlorine-rich frameworks, substantially lowering migration barriers for Mg-ion transport. This work demonstrates that deliberate control of local Mg-ion coordination and lattice softness through partial anion exchange in amorphous halide systems can overcome the intrinsic transport limitations of divalent Mg-ions. For Li-ion conduction, this thesis investigates earth-abundant halide electrolytes based on inverse spinel structures. Using Li2MgCl4 as a model system, molecular dynamics simulations reveal that lithium disordering from tetrahedral 8a to octahedral 16c sites significantly lowers the activation energy for Li-ion migration. Guided by these insights, aliovalent zirconium substitution is employed to stabilize cation disorder at room temperature, leading to marked enhancements in ionic conductivity. By decoupling the effects of lithium deficiency level and cation disorder, this work demonstrates that site disorder within the halide framework plays a dominant role in enabling fast lithium transport in inverse spinel electrolytes. This thesis further explores fluorination as a chemical lever to simultaneously enhance ionic conductivity and electrochemical stability in lithium halide electrolytes. In a crystalline LiAlCl4 system, partial substitution of chlorine with fluorine induces lithium deficiency and aluminum excess while preserving the overall monoclinic framework. Multimodal structural characterization shows that fluorination increases the diversity and distortion of local lithium coordination environments and weakens Li–F interactions through preferential Al–F bonding. The optimized fluorinated halide electrolyte exhibits improved Li-ion conductivity and stability against a lithium metal anode. Moreover, fluorination enables access to metastable orthorhombic phases that are inaccessible through conventional synthesis routes, highlighting the critical role of metastability in tuning ion transport. Overall, this thesis establishes halide electrolytes as a versatile and chemically tunable platform for solid-state ion transport in both lithium and multivalent battery systems. By elucidating how cation disorder, anion chemistry, and complex local coordination environments regulate ionic mobility, this work connects ion transport behavior across amorphous and crystalline halide frameworks and identifies common underlying design principles. These insights provide actionable guidance for the rational design of next-generation solid-state electrolytes that combine fast ion conduction, interfacial robustness, and compositional sustainability.