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The factorial growth of topological recursion
No full textWe show that the n -point, genus- g correlation functions of topological recursion on any regular spectral curve with simple ramifications grow at most like (2g-2+n)!as g→∞, which is the expected growth rate. This provides, in particular, an upper bound for many curve counting problems in large genus and serves as a preliminary step for a resurgence analysis.Open access funding provided by Swiss Federal Institute of Technology ZurichSwiss Federal Institute of Technology ZurichPeer Reviewe
Integrable systems: From the ice rule to supersymmetric fishnet Feynman diagrams
No full textDiese Dissertation untersucht den Zusammenhang zwischen Modellen der statistischen Physik und Feynman-Diagrammen in Quantenfeldtheorien, anhand einer gemeinsamen Eigenschaft, der Integrabilität. In beiden Fällen betrachten wir integrable Strukturen für periodische Randbedingungen und setzen dabei unseren Fokus auf das Acht- und Sechs-Vertex-Modell, sowie die bi-skalare Fischnetz-Theorie. Letztere ist eine gewisse deformierte Version der N = 4 supersymmetrischen Yang-Mills-Theorie. Wir geben einen Überblick über eine bekannte Anwendung von Integrabilität in diesen Theorien, nämlich die Berechnung der freien Energie im thermodynamischen Limes und ihr Gegenstück in Quantenfeldtheorien, die kritische Kopplungsstärke. Auch wiederholen wir die Berechnung anomaler Dimensionen und Koeffizienten der Operator-Produkt Entwicklung (OPE) in der konformen Fischnetz-Feldtheorie, dessen Ergebnis zu beliebiger Schleifenordnung bestimmt werden kann. Die neuen Erkenntnisse dieser Arbeit umfassen die Ergebnisse zur kritischen Kopplungsstärke für gewisse Modelle mit Fermionen. Genauer handelt es sich dabei um die Brick-Wall-Theorie und die fermionische Fischnetz-Theorie. Darüber hin-
aus verallgemeinern wir die Studien integrabler Feynman-Diagramme für supersymmetrische Diagramme. Dank der Entwicklung eines effizienten graphischen Formalismus sind wir in der Lage die kritische Kopplungsstärke von starken Deformationen der N = 4 Super-Yang-Mills-Theorie sowie der ABJM-Theorie zu bestimmen, die sogenannte Super-Brick-Wall- und Superfishnet-Theorie. Desweitern leiten wir nützliche Superraumtechniken her, die uns erlauben die anomale Skalendimension und einen OPE-Koeffizienten zu beliebiger Schleifenordung zu bestimmen. Zudem untersuchen wir die Rand-Integrabilität im Sechs-Vertex-Modell und in Feynman-Diagrammen. Wir präsentieren neue, kastenförmige Randbedingungen für das Sechs-Vertex-Modell und postulieren eine geschlossene Form der Zustandssumme bei beliebiger Gittergröße.This thesis examines the correspondence between models of statistical physics and Feynman graphs of quantum field theories by a common property: integrability. We review integrable structures for periodic boundary conditions on both sides, while focusing on the eight- and six-vertex model and the bi-scalar fishnet theory. The latter is a double-scaled γ-deformations of N = 4 super Yang-Mills theory. Interesting applications of integrability existing in the literature that we reconsider are the computation of the free energy in the thermodynamic limit and its quantum field theory (QFT) counterpart, the critical coupling. In addition, we provide a detailed overview of the calculation of exact anomalous dimensions and operator product expansion (OPE) coefficients in the conformal bi-scalar fishnet theory. The original contributions of this work comprise the results of the critical coupling for models with fermions, the brick wall theory, and the fermionic fishnet theory. Additionally, we extend the study of integrable Feynman graphs to supersymmetric diagrams in superspace. By establishing an efficient graphical formalism, we obtain the critical coupling of double-scaled β-deformations of N = 4 super Yang-Mills theory and Aharony-Bergman-Jafferis-Maldacena theory, the super brick wall and superfishnet theory, respectively. Moreover, we apply superspace methods to the superfishnet theory and find results for anomalous dimensions and an OPE coefficient, which are all-loop exact in the coupling. In addition, we study boundary integrability in the six-vertex model and for Feynman diagrams. We present new box-shaped boundary conditions for the six-vertex model and conjecture a closed form for its partition function at any lattice size. On the QFT side, we find integrable boundary scattering matrices in the form of generalized Feynman diagrams by graphical methods
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No full textMimicking the CuD Site of pMMO via a Copper Cage‐Complex
No full textThe mechanism of action of particulate monooxygenase (pMMO) has yet to be determined. The CuD site with two histidines and an asparagine coordinating to copper has been identified as a potential active site of pMMO. Here, we present a copper cage complex, that assembles this coordination sphere, being a structural mimic of the pMMO. The cage is capable to catalyze aerobic oxidations of organic substrates such as benzylic alcohols to aldehydes and hydroquinones to quinones. This is inspired by the reactivity that is observed for enzymatic active sites possessing copper.Deutsche Forschungsgemeinschaft 10.13039/501100001659Peer Reviewe
‘I Slashed My Mom's Car Tires So We Wouldn't Have to Go Back to Germany’: (Non)Belonging and Mobility Among Descendants of Poles in Germany
No full textDespite growing scholarly interest in youth mobility, research among the descendants of migrants often focuses on travel between their country of residence and their parents' country of origin. This limited perspective risks obscuring the interconnections between different forms of mobility and their influence on individuals' lives. Drawing on autobiographical interviews with individuals raised by Polish parents in Germany, this article explores their varied transnational practices in relation to (non)belonging. While a growing body of literature addresses challenges faced by Eastern European migrants, their descendants receive less scholarly attention. Often perceived as ‘invisible’ due to assumptions of seamless integration, they nonetheless encounter stigma and exclusion. This study demonstrates how movements across different places and social contexts positioned participants in a liminal space of non‐belonging and contributed to the devaluation, rejection, or romanticization of their connection to their parents' homeland. It argues that transnational mobility both reinforced non‐belonging and served as a way of coping with it. By centring non‐belonging, the study identifies the specific processes that led to it and its impact on life decisions.Peer Reviewe
Responses of riverine dissolved organic matter to damming in two distinct hydrological regimes in northern Spain
No full textIberian rivers are characterized by flow regimes with high seasonal flow variation. They also host one-fifth of Europe's reservoirs for hydropower generation, irrigation, or water supply needs, and thus many rivers in this region have heavily altered flow regimes. Such flow conditions also alter the natural dynamics of dissolved organic matter (DOM), which likely has implications for carbon cycling due to changed conditions for the transformation, transportation, production, and storage of carbon. Here we looked into the effects of flow alteration on the DOM regime, i.e. the seasonal variation in DOM concentration and composition, in 20 rivers belonging to two different natural (reference) flow regimes (i.e. Mediterranean and Atlantic) in northern Spain. To further investigate which flow regime components influence DOM properties, we linked the observed seasonal shifts in DOM composition to a range of hydrological indices. We found that Atlantic rivers with a natural flow regime tended to have lower annual mean dissolved organic carbon (DOC) concentrations than their altered equivalents; this flow alteration trend is weakly mirrored in Mediterranean rivers. We did not observe much difference in annual average DOM composition due to flow alteration in either Atlantic or Mediterranean rivers. However, the seasonal variation in DOM composition was lower in altered Atlantic rivers compared to natural ones. This flow alteration effect on the DOM regime was not as distinctive in Mediterranean rivers, which showed a higher diversity of DOM regimes across rivers. We linked the lack of seasonal variation in DOM composition in flow-altered rivers mainly to the prevention of transmission of upstream-sourced DOM from the reservoirs. It appears that in our study area, reservoirs mostly act as a temporally homogenizing buffer, averaging out naturally occurring shifts in DOM composition by transiently storing upstream-sourced carbon inputs and subjecting them to bio- and photo-degradation, thus sending relatively invariable amounts of DOM further downstream. This effect of dams on DOM regimes appears robust across both Atlantic and Mediterranean regimes despite some heterogeneity of dam types and purposes, with potentially important consequences for riverine carbon cycling.H2020 Marie Skłodowska-Curie ActionsPeer Reviewe
Hydrosocial Territories Research: An Overview
No full textHydrosocial territories scholarship has contributed to advancing relational, power‐sensitive, multiscalar understandings of water and its governance. Grounded in critical water studies, political ecology, and political geography, this scholarship draws attention to how water distributions are contested between different interest groups and their respective notions of how water is and should be governed at multiple interrelated spatial and temporal scales. We provide an overview of the literature on hydrosocial territories with the objective of tracing the development and application of this framework since its introduction in the mid‐2010s. The article summarizes how hydrosocial territories research has developed conceptually, methodologically, and thematically. We find that hydrosocial territories research employs largely qualitative methodologies to study water‐related disputes surrounding a diversity of themes including hydraulic infrastructures, agricultural production and export, urbanization, river basin management, extractive industries, and conservation. We conclude with a reflection on potential ways forward for hydrosocial territories scholarship.Los estudios sobre territorios hidrosociales han contribuido a promover una comprensión relacional, sensible a las tensiones de poder y la multiescalridad del agua y su gobernanza. Con base en los estudios críticos sobre el agua, la ecología política y la geografía política, estos estudios llama la atención sobre cómo las distribuciones de agua en disputa entre diferentes grupos de interés y sus respectivas nociones de cómo se gobierna y debería gobernarse el agua a través de múltiples escalas espaciales y temporales interrelacionadas. Ofrecemos una visión general de la bibliografía sobre territorios hidrosociales con el objetivo de rastrear el desarrollo y la aplicación de este marco desde su introducción a mediados de la década de 2010. El artículo resume cómo se ha desarrollado conceptual, metodológica y temáticamente la investigación sobre territorios hidrosociales. Hallamos que la investigación sobre territorios hidrosociales emplea en gran medida metodologías cualitativas para estudiar disputas relacionadas con el agua en torno a una diversidad de temas como infraestructuras hidráulicas, producción y exportación agrícola, urbanización, gestión de cuencas hidrográficas, industrias extractivas y conservación. Concluimos con una reflexión sobre aproximaciones futuras para los estudios sobre territorios hidrosociales.Volkswagen Foundation 10.13039/501100001663Peer Reviewe
Bond Dissociation Dynamics of Single Molecules on a Metal Surface
No full textThe breaking of an interatomic bond is at the heart of chemistry yet remains a challenge to be investigated. Molecules on metal surfaces exhibit defined positions and orientations and can be characterized by scanning tunneling microscopy that moreover is able to trigger bond breaking. Until now, the bond dissociation dynamics has been studied in small molecules but not in large ones with various degrees of freedom. Here, we dissociate bromine atoms from single dibromo-terfluorene molecules on Ag(111), identifying not only the displacement but also the rotation of each fragment. It turns out that the molecular excitation that causes dissociation is not locally confined. Instead, it can propagate through the molecule, and the dynamics of the resulting fragments is uncorrelated. The fragment binds to the nearest silver atom after dissociation and dissipates its energy in rotational motion. Our findings could be useful for the precise engineering of chemical reactions with prearranged precursor molecules.Peer Reviewe
A Participatory Scenario Framework Advances Ecosystem Scenarios as Environmental Futures Approach
No full textEcosystem scenarios describe possible, probable and desirable developments of the natural environment in the future, often assessed from a natural scientific (biophysical) and social scientific (socioeconomic) perspective. Processing relevant systemic and human behavioral parameters as scenario factors or drivers, different frameworks for ecosystem scenario building have been developed, applied, and evaluated in scientific literature. Increasingly, stakeholder participation has proven a central objective and challenge for these frameworks defining process designs in transdisciplinary domains such as science‐society or science‐policy interfaces. This article presents a conceptual framework to advance ecosystem scenario projects towards improved stakeholder participation, knowledge inclusivity and process reflexivity. The framework combines epistemological and methodological elements from futures studies with established research practices in ecosystem assessment projects. The framework's dynamic, adaptive character adds deliberative and reflexive elements to process design and application for a more inclusive and stakeholder‐oriented research practice. Its novelty lies in the continuous configuration of process variables derived from common dichotomous elements of theoretical scenario classification applied in scenario practice. This approach benefits integrated knowledge management and inclusivity within the framework for multi‐method, multi‐stakeholder, multi‐sector and multi‐epistemic scenario processes. In a wider scope of environmental futures approaches, this article details the development, conceptual outline and preliminary application of the participatory framework for testing and evaluation in an ongoing ecosystem scenario project.The author received no specific funding for this work.Peer Reviewe