A Loadlock Platform for Next-Generation Quantum Optics Experiments

This PhD thesis presents the design, development, and implementation of a loadlock platform tailored for next-generation quantum optics experiments. Quantum optics, a field at the forefront of both fundamental research and technological innovation, relies heavily on precise control over light-matter interactions. To advance this field, the thesis provides a comprehensive exploration of the theoretical and experimental foundations of quantum optics, followed by a detailed examination of the loadlock platform's role in enhancing experimental capabilities

Dynamics and kinetics in structural biology: The example of DNA photolyase

All biochemical reactions directly involve structural changes that may occur over a very wide range of timescales from femtoseconds to seconds. Understanding the mechanism of action thus requires determination of both the static structures of the macromolecule involved and short-lived intermediates between reactant and product. This requires either freeze-trapping of intermediates, for example by cryo-electron microscopy, or direct determination of structures in active systems at near-physiological temperature by time-resolved X-ray crystallography. Storage ring X-ray sources effectively cover the time range down to around 100 ps that reveal tertiary and quaternary structural changes in proteins. The briefer pulses emitted by hard X-ray free electron laser sources extend that range to femtoseconds, which covers critical chemical reactions such as electron transfer, isomerization, breaking of covalent bonds, and ultrafast structural changes in light-sensitive protein chromophores and their protein environment. These reactions are exemplified by the time-resolved X-ray studies by two groups of the FAD-based DNA repair enzyme, DNA photolyase, over the time range from 1 ps to 100 μs

Spacing Statues: Interpreting Curatorial Interventions on Roman Aedicular Facades

Multi-story aedicular façades, featuring rows of statue-bearing niches and aediculae, transformed the theaters of Roman Anatolia (modern-day Türkiye) into carefully curated multimedia environments. This dissertation investigates the stages façades (scaenae frontes) of five such theaters—Aphrodisias, Miletus, Ephesus, Hierapolis, and Perge—constructed between the Augustan and Severan periods. By examining the interplay of statues, inscriptions, and reliefs within the façades’ architectural syntax, this study reconstructs how scaenae frontes functioned as hypermediated environments, or spaces designed to draw attention to the act of representation itself. It approaches the display of statuary as both a curatorial and interpretive enterprise, considering interventions as staged acts that constitute cultural performances. Each chapter examines curatorial intervention through a site-specific lens, highlighting the adaptability of the aedicular façade format to different cultural and historical contexts. At Aphrodisias, sculptural display is revealed as an ongoing process, with inscriptions on the logeion terrace documenting the strategic placement of both new and restored statues, underscoring restoration as an active curatorial choice. Miletus incorporates true antiquities, statues predating the façade’s construction by centuries, creating a deliberate dialogue between past and present and reinforcing local identity. The scaenae frons at Ephesus accommodates a broad spectrum of statue sizes, demonstrating how scale and typological variety shaped curatorial strategy. Hierapolis presents an intermedial approach, orchestrating freestanding statues and reliefs to reinforce thematic connections across media, with inscriptions providing crucial contextual information. Perge showcases the high degree of curatorial planning required to integrate statues of varied compositions as thematic pendants, with an extraordinarily high degree of coordination between architectural positions and individual statues. These findings demonstrate that aedicular façades were not merely decorative backdrops but dynamic, interpretive spaces, where curatorial decisions operated as acts of cultural performance, shaping evolving dialogues about identity, power, and memory. By reframing scaenae frontes as hypermediated environments, this study redefines their role within Roman sculptural display practices, demonstrating that these sculptural programs were not only curated but also staged, engaging audiences in a process of interpretation that paralleled the theatrical and civic performances unfolding before them. This approach offers new perspectives on the communicative potential of aedicular façades across various civic contexts in Roman Anatolia and beyond

Mapping Class Groups of Del Pezzo Surfaces and Lefschetz Fibrations

This thesis comprises four papers on topics around the topological mapping class groups of del Pezzo and rational surfaces and the topology of 4-dimensional Lefschetz fibrations. Chapters 2 and 3 address the Nielsen realization problem for various finite subgroups of the mapping class groups of del Pezzo surfaces. Chapter 4, which is joint work with Carlos A. Serván, exhibits examples of Lefschetz fibrations with infinitely many homologically distinct symplectic sections. Finally, Chapter 5 studies the stabilizer of isotropic homology classes of minimal genus 0 in rational 4-manifolds under the action of the mapping class group

Legalized Violence, Illegal Defense: The Extreme Violence Against Trans Persons in U.S. Prisons

The legally permitted abuse of transgender individuals in the carceral system is a dangerous epidemic that has hit an extreme peak in the past two decades. This issue is further exacerbated, by the extreme overrepresentation of trans persons in prison compared to that of the general population. Moreover, the legal doctrine and laws that should serve as protective barriers for transgender persons in prison have woefully failed in achieving such ends. This review provides an extensive exploration into such legal doctrine to better understand the procedures of these shortcomings and failures. The legal exploration centers the landmark 1994 SCOTUS ruling on the Farmer v. Brennan prison violence case, in conjunction with the Prison Rape Elimination Act (PREA) passed by Congress in 2003. The findings indicate that a flawed interpretation in judicial rulings and missing enforceability, accountability, and applicability structures within these laws all contribute to the dismal state of these legal structures that should be protecting trans persons in prison from increased violence. This legal review concludes with recommended legal reforms and places emphasis on a short term expansion of provisions for equitable societal support measures for trans persons, and a long term solution requiring the abolition of the carceral system

Interfacial Electronic Structure Probed by Sum Frequency Generation Spectroscopy and Transient Absorption

Interfacial electronic structure is of critical importance to a variety of systems including biological, photovoltaics, and spintronic devices. The ability to measure and quantify this interfacial structure is necessary to engineer these systems in a targeted, informed manner; however, efforts to do so are often stymied by the fact that bulk signal tends to overwhelm interfacial signal. There are two experimental approaches to accessing the interface: (1) interface specific spectroscopic techniques and (2) bulk sensitive measurements on thin film samples, which can be considered "all interface." In this Dissertation, I present efforts and achievements in both of these approaches. In Chapter 2 I describe the underlying principles of sum frequency generation (SFG) spectroscopy, an interface specific technique, and the experimental challenges and requirements to achieve robust SFG spectra in the electronic regime. Chapter 3 details the design of a phase stable interferometer that meets many of these challenges and shows a dramatic improvement in the signal-to-noise of SFG spectra. To address the case of thin film samples, I focus in particular on molybdenum disulfide (MoS2) a two-dimensional material that is a direct bandgap semiconductor in the monolayer limit. MoS2 and other transition metal dichalcogenides (TMDs) are of significant interest in modern electronics, due in particular to their tunability, ease of functionalization, and spin split band structure. This system is measured with transient absorption spectroscopy, a bulk sensitive technique, and variants thereof. Chapter 4 describes the spectroscopic and structural properties of MoS2 and other TMDs. Chapter 5 details a particular instance of laser induced modification in monolayer MoS2. Chapter 6 explores the spectral effect of modifying MoS2 with a thin film organic semiconductor. Lastly, Chapter 7 describes ongoing efforts to characterize the effect of functionalizing MoS2 with chiral molecules. The work presented here represents a significant advance in experimental probes of chemical interfaces and in our understanding of the ultrafast behavior of modified MoS2

Molecular Epidemiologic and Geo-Spatial Characterization of <i>Staphylococcus aureus</i> Cultured from Skin and Soft Tissue Infections from United States-Born and Immigrant Patients Living in New York City

(1) Background: With increasing international travel and mass population displacement due to war, famine, climate change, and immigration, pathogens, such as Staphylococcus aureus (S. aureus), can also spread across borders. Methicillin-resistant S. aureus (MRSA) most commonly causes skin and soft tissue infections (SSTIs), as well as more invasive infections. One clonal strain, S. aureus USA300, originating in the United States, has spread worldwide. We hypothesized that S. aureus USA300 would still be the leading clonal strain among US-born compared to non-US-born residents, even though risk factors for SSTIs may be similar in these two populations (2) Methods: In this study, 421 participants presenting with SSTIs were enrolled from six community health centers (CHCs) in New York City. The prevalence, risk factors, and molecular characteristics for MRSA and specifically clonal strain USA300 were examined in relation to the patients’ self-identified country of birth. (3) Results: Patients born in the US were more likely to have S. aureus SSTIs identified as MRSA USA300. While being male and sharing hygiene products with others were also significant risks for MRSA SSTI, we found exposure to animals, such as owning a pet or working at an animal facility, was specifically associated with risk for SSTIs caused by MRSA USA300. Latin American USA300 variant (LV USA300) was most common in participants born in Latin America. Spatial analysis showed that MRSA USA300 SSTI cases were more clustered together compared to other clonal types either from MRSA or methicillin-sensitive S. aureus (MSSA) SSTI cases. (4) Conclusions: Immigrants with S. aureus infections have unique risk factors and S. aureus molecular characteristics that may differ from US-born patients. Hence, it is important to identify birthplace in MRSA surveillance and monitoring. Spatial analysis may also capture additional information for surveillance that other methods do not

Erasing “bad memories”: Reversing aberrant synaptic plasticity as therapy for neurological and psychiatric disorders

Dopamine modulates corticostriatal plasticity in both the direct and indirect pathways of the cortico-striato-thalamo-cortical (CSTC) loops. These gradual changes in corticostriatal synaptic strengths produce long-lasting changes in behavioral responses. Under normal conditions, these mechanisms enable the selection of the most appropriate responses while inhibiting others. However, under dysregulated dopamine conditions, including a lack of dopamine release or dopamine signaling, these mechanisms could lead to the selection of maladaptive responses and/or the inhibition of appropriate responses in an experience-dependent and task-specific manner. In this review, we propose that preventing or reversing such maladaptive synaptic strengths and erasing such aberrant “memories” could be a disease-modifying therapeutic strategy for many neurological and psychiatric disorders. We review evidence from Parkinson’s disease, drug-induced parkinsonism, L-DOPA-induced dyskinesia, obsessive-compulsive disorder, substance use disorders, and depression as well as research findings on animal disease models. Altogether, these studies allude to an emerging theme in translational neuroscience and promising new directions for therapy development. Specifically, we propose that combining pharmacotherapy with behavioral therapy or with deep brain stimulation (DBS) could potentially cause desired changes in specific neural circuits. If successful, one important advantage of correcting aberrant synaptic plasticity is long-lasting therapeutic effects even after treatment has ended. We will also discuss the potential molecular targets for these therapeutic approaches, including the cAMP pathway, proteins involved in synaptic plasticity as well as pathways involved in new protein synthesis. We place special emphasis on RNA binding proteins and epitranscriptomic mechanisms, as they represent a new frontier with the distinct advantage of rapidly and simultaneously altering the synthesis of many proteins locally

Regulator Beliefs

Modern financial regulations are forward-looking and operationally rely on regulator models to forecast future outcomes. As a result, through these models, regulations embed views about the future, which I term regulator beliefs. Using the US life insurance sector, I measure regulator and insurer interest rate expectations. Deriving regulator expectations from the economic model they prescribe for risk-based capital and policy reserve calculations, and gathering insurer expectations from investor call transcripts using a large language model. I document three stylized facts: (i) Regulators and insurers disagree about future yields, with disagreement exceeding 2pp for long-horizon expectations; (ii) Regulator expectations missed the decline in yields, but they predict future yields just as, if not more, accurately as professional forecasters and insurers; and (iii) Regulators and professional forecasters exhibit quantitatively similar belief-updating patterns, such as underreacting to new information. In line with large disagreements, I show that regulator expectations induce insurers to adjust their actions materially. Two quasi-experiments confirm that insurers rebalance portfolios to align with regulator expectations—adjusting portfolio duration by over 15\%. Furthermore, insurers shift their reported expectations to be more aligned with the regulator—highlighting the need to consider the regulatory environment when interpreting institutional investors' reported beliefs. Finally, I extend the analysis to banks, demonstrating that shifts in Federal Reserve beliefs, due to their influence on stress test design, cause banks to adjust their capital allocations. Overall, the findings lay the groundwork for a broader agenda connecting regulator beliefs to financial institution decisions, asset prices, and financial stability

Formation of the 15 Å phase as the most expanded hydrated mineral in cold subduction zone

Talc, as an important class of clay minerals constituting subducting oceanic crust, has long been known to undergo interlayer expansion by ~6% to contain net ~13 wt.% water into the ‘so-called’ 10 Å phase. Although subduction fluid is mildly alkaline and includes various salts and other dissolved species, its effect on the stability of subducting minerals has not yet been considered. Here, we report that subducting talc, when exposed to alkaline salty water conditions, breaks down to form a super-hydrated 15 Å phase at ~3.0 GPa and ~350 °C, corresponding to a depth of ~90–95 km along a cold subduction geotherm. The 15 Å phase remains stable down to ~125 km depth, where it transforms into the previously known 10 Å phase. Our combined experimental and computational results show that the super-hydrated 15 Å phase contains net ~31 wt.% water through interlayer expansion by ~60%. Our work thus demonstrates mineral transformation under more realistic subduction environments, which calls for reevaluation of subduction-related geochemistry and seismicity as well as water transportation into the deep Earth