@unpublished{21691, abstract = {Light-matter interaction with squeezed vacuum has received much interest for the ability to enhance the native interaction strength between an atom and a photon with a reservoir assumed to have an infinite bandwidth. Here, we study a model of parametrically driven cavity quantum electrodynamics (cavity QED) for enhancing light-matter interaction while subjected to a finite-bandwidth squeezed vacuum drive. Our method is capable of unveiling the effect of relative bandwidth as well as squeezing required to observe the anticipated anti-crossing spectrum and enhanced cooperativity without the ideal squeezed bath assumption. Furthermore, we analyze the practicality of said models when including intrinsic photon loss due to resonators imperfection. With these results, we outline the requirements for experimentally implementing an effectively squeezed bath in solid-state platforms such as InAs quantum dot cavity QED such that \textit{in situ} control and enhancement of light-matter interaction could be realized.}, author = {Lê, Trung Kiên and Lukin, Daniil M. and Roques-Carmes, Charles and Karnieli, Aviv and Lustig, Eran and Guidry, Melissa A. and Fan, Shanhui and Vučković, Jelena}, booktitle = {arXiv}, title = {{Cavity quantum electrodynamics in finite-bandwidth squeezed reservoir}}, doi = {10.48550/arXiv.2412.15068}, year = {2024}, } @unpublished{21684, abstract = {This study focuses on advancing metascintillators to break the 100 ps barrier and approach the 10 ps target. We exploit nanophotonic features, specifically the Purcell effect, to shape and enhance the scintillation properties of the first-generation metascintillator. We demonstrate that a faster emission is achievable along with a more efficient conversion efficiency. This results in a coincidence time resolution improved by a factor of 1.6, crucial for TOF-PET applications.}, author = {Shultzman, Avner and Schütz, Roman and Kurman, Yaniv and Lahav, Neta and Dosovitskiy, George and Roques-Carmes, Charles and Bekenstein, Yehonadav and Konstantinou, Georgios and Latella, Riccardo and Zhang, Lei and Francis Loignon-Houle, Francis Loignon-Houle and Gonzalez, Antonio J. and Benlloch, José María and Kaminer, Ido and Lecoq, Paul}, booktitle = {arXiv}, title = {{Towards a second generation of metascintillators using the Purcell effect}}, doi = {10.48550/arXiv.2406.15058}, year = {2024}, } @unpublished{21680, abstract = {Multimode squeezed light is enticing for several applications, from squeezed frequency combs for spectroscopy to signal multiplexing in optical computing. To generate squeezing in multiple frequency modes, optical parametric oscillators have been vital in realizing multimode squeezed vacuum states through second-order nonlinear processes. However, most work has focused on generating multimode squeezed vacua and squeezing in mode superpositions (supermodes). Bright squeezing in multiple discrete frequency modes, if realized, could unlock novel applications in quantum-enhanced spectroscopy and optical quantum computing. Here, we show how $Q$ factor engineering of a multimode nonlinear cavity with cascaded three wave mixing processes creates strong, spectrally tunable single mode output amplitude noise squeezing over 10 dB below the shot noise limit. In addition, we demonstrate squeezing for multiple discrete frequency modes above threshold. This bright squeezing arises from enhancement of the (noiseless) nonlinear rate relative to decay rates in the system due to the cascaded generation of photons in a single idler "bath" mode. A natural consequence of the strong nonlinear coupling in our system is the creation of an effective cavity in the synthetic frequency dimension that sustains Bloch oscillations in the modal energy distribution. Bloch mode engineering could provide an opportunity to better control nonlinear energy flow in the synthetic frequency dimension, with exciting applications in quantum random walks and topological photonics. Lastly, we show evidence of long-range correlations in amplitude noise between discrete frequency modes, pointing towards the potential of long-range entanglement in a synthetic frequency dimension.}, author = {Pontula, Sahil and Salamin, Yannick and Roques-Carmes, Charles and Soljacic, Marin}, booktitle = {arXiv}, title = {{Multimode amplitude squeezing through cascaded nonlinear optical processes}}, doi = {10.48550/arXiv.2405.05201}, year = {2024}, } @unpublished{21679, abstract = {The observation that free electrons can interact coherently with quantized electromagnetic fields and matter systems has led to a plethora of proposals leveraging the unique quantum properties of free electrons. At the heart of these proposals lies the assumption of a strong quantum interaction between a flying free electron and a photonic mode. However, existing schemes are intrinsically limited by electron diffraction, which puts an upper bound on the interaction length and therefore the quantum coupling strength. Here, we propose the use of "free-electron fibers'': effectively one-dimensional photonic systems where free electrons co-propagate with two guided modes. The first mode applies a ponderomotive trap to the free electron, effectively lifting the limitations due to electron diffraction. The second mode strongly couples to the guided free electron, with an enhanced coupling that is orders of magnitude larger than previous designs. Moreover, the extended interaction lengths enabled by our scheme allows for strong single-photon nonlinearities mediated by free electrons. We predict a few interesting observable quantum effects in our system, such as deterministic single-photon emission and complex, nonlinear multimode dynamics. Our proposal paves the way towards the realization of many anticipated effects in free-electron quantum optics, such as non-Gaussian light generation, deterministic single photon emission, and quantum gates controlled by free-electron--photon interactions.}, author = {Karnieli, Aviv and Roques-Carmes, Charles and Rivera, Nicholas and Fan, Shanhui}, booktitle = {arXiv}, title = {{Strong coupling and single-photon nonlinearity in free-electron quantum optics}}, doi = {10.48550/arXiv.2403.13071}, year = {2024}, } @unpublished{21681, abstract = {Enhancing interactions in many-body quantum systems, while protecting them from environmental decoherence, is at the heart of many quantum technologies. Waveguide quantum electrodynamics is a promising platform for achieving this, as it hosts infinite-range interactions and decoherence-free subspaces of quantum emitters. However, as coherent interactions between emitters are typically washed out in the wavelength-spacing regime hosting decoherence-free states, coherent control over the latter becomes limited, and many-body Hamiltonians in this important regime remain out of reach. Here we show that by incorporating emitter arrays with nonlinear waveguides hosting parametric gain, we obtain a unique class of many-body interaction Hamiltonians with coupling strengths that increase with emitter spacing, and persist even for wavelength-spaced arrays. We then propose to use these Hamiltonians to coherently generate decoherence-free states directly from the ground state, using only global squeezing drives, without the need for local addressing of individual emitters. Interestingly, we find that the dynamics approaches a unitary evolution in the limit of weak intra-waveguide squeezing, and discuss potential experimental realizations of this effect. Our results pave the way towards coherent control protocols in waveguide quantum electrodynamics, with applications including quantum computing, simulation, memory and nonclassical light generation.}, author = {Karnieli, Aviv and Tziperman, Offek and Roques-Carmes, Charles and Fan, Shanhui}, booktitle = {arXiv}, title = {{Decoherence-free many-body Hamiltonians in nonlinear waveguide quantum electrodynamics}}, doi = {10.48550/arXiv.2405.20241}, year = {2024}, } @unpublished{21683, abstract = {Optical computing often employs tailor-made hardware to implement specific algorithms, trading generality for improved performance in key aspects like speed and power efficiency. An important computing approach that is still missing its corresponding optical hardware is probabilistic computing, used e.g. for solving difficult combinatorial optimization problems. In this study, we propose an experimentally viable photonic approach to solve arbitrary probabilistic computing problems. Our method relies on the insight that coherent Ising machines composed of coupled and biased optical parametric oscillators can emulate stochastic logic. We demonstrate the feasibility of our approach by using numerical simulations equivalent to the full density matrix formulation of coupled optical parametric oscillators.}, author = {Horodynski, Michael and Roques-Carmes, Charles and Salamin, Yannick and Choi, Seou and Sloan, Jamison and Luo, Di and Soljačić, Marin}, booktitle = {arXiv}, title = {{Stochastic logic in biased coupled photonic probabilistic bits}}, doi = {10.48550/arXiv.2406.04000}, year = {2024}, } @article{12875, abstract = {The superior colliculus (SC) in the mammalian midbrain is essential for multisensory integration and is composed of a rich diversity of excitatory and inhibitory neurons and glia. However, the developmental principles directing the generation of SC cell-type diversity are not understood. Here, we pursued systematic cell lineage tracing in silico and in vivo, preserving full spatial information, using genetic mosaic analysis with double markers (MADM)-based clonal analysis with single-cell sequencing (MADM-CloneSeq). The analysis of clonally related cell lineages revealed that radial glial progenitors (RGPs) in SC are exceptionally multipotent. Individual resident RGPs have the capacity to produce all excitatory and inhibitory SC neuron types, even at the stage of terminal division. While individual clonal units show no pre-defined cellular composition, the establishment of appropriate relative proportions of distinct neuronal types occurs in a PTEN-dependent manner. Collectively, our findings provide an inaugural framework at the single-RGP/-cell level of the mammalian SC ontogeny.}, author = {Cheung, Giselle T and Pauler, Florian and Koppensteiner, Peter and Krausgruber, Thomas and Streicher, Carmen and Schrammel, Martin and Özgen, Natalie Y and Ivec, Alexis and Bock, Christoph and Shigemoto, Ryuichi and Hippenmeyer, Simon}, issn = {0896-6273}, journal = {Neuron}, number = {2}, pages = {230--246.e11}, publisher = {Elsevier}, title = {{Multipotent progenitors instruct ontogeny of the superior colliculus}}, doi = {10.1016/j.neuron.2023.11.009}, volume = {112}, year = {2024}, } @article{14683, abstract = {Mosaic analysis with double markers (MADM) technology enables the generation of genetic mosaic tissue in mice and high-resolution phenotyping at the individual cell level. Here, we present a protocol for isolating MADM-labeled cells with high yield for downstream molecular analyses using fluorescence-activated cell sorting (FACS). We describe steps for generating MADM-labeled mice, perfusion, single-cell suspension, and debris removal. We then detail procedures for cell sorting by FACS and downstream analysis. This protocol is suitable for embryonic to adult mice. For complete details on the use and execution of this protocol, please refer to Contreras et al. (2021).1}, author = {Amberg, Nicole and Cheung, Giselle T and Hippenmeyer, Simon}, issn = {2666-1667}, journal = {STAR Protocols}, keywords = {General Immunology and Microbiology, General Biochemistry, Genetics and Molecular Biology, General Neuroscience}, number = {1}, publisher = {Elsevier}, title = {{Protocol for sorting cells from mouse brains labeled with mosaic analysis with double markers by flow cytometry}}, doi = {10.1016/j.xpro.2023.102771}, volume = {5}, year = {2024}, } @article{17187, abstract = {The generation of diverse cell types during development is fundamental to brain functions. We outline a protocol to quantitatively assess the clonal output of individual neural progenitors using mosaic analysis with double markers (MADM) in mice. We first describe steps to acquire and reconstruct adult MADM clones in the superior colliculus. Then we detail analysis pipelines to determine clonal composition and architecture. This protocol enables the buildup of quantitative frameworks of lineage progression with precise spatial resolution in the brain. For complete details on the use and execution of this protocol, please refer to Cheung et al.1}, author = {Cheung, Giselle T and Streicher, Carmen and Hippenmeyer, Simon}, issn = {2666-1667}, journal = {STAR Protocols}, number = {3}, publisher = {Elsevier}, title = {{Protocol for quantitative reconstruction of cell lineage using mosaic analysis with double markers in mice}}, doi = {10.1016/j.xpro.2024.103157}, volume = {5}, year = {2024}, } @article{17232, abstract = {The lineage relationship of clonally-related cells offers important insights into the ontogeny and cytoarchitecture of the brain in health and disease. Here, we provide a protocol to concurrently assess cell lineage relationship and cell-type identity among clonally-related cells in situ. We first describe the preparation and screening of acute brain slices containing clonally-related cells labeled using mosaic analysis with double markers (MADM). We then outline steps to collect RNA from individual cells for downstream applications and cell-type identification using RNA sequencing. For complete details on the use and execution of this protocol, please refer to Cheung et al. 1}, author = {Cheung, Giselle T and Pauler, Florian and Koppensteiner, Peter and Hippenmeyer, Simon}, issn = {2666-1667}, journal = {STAR Protocols}, number = {3}, publisher = {Elsevier}, title = {{Protocol for mapping cell lineage and cell-type identity of clonally-related cells in situ using MADM-CloneSeq}}, doi = {10.1016/j.xpro.2024.103168}, volume = {5}, year = {2024}, } @inbook{17425, abstract = {Mosaic Analysis with Double Markers (MADM) is a powerful genetic method typically used for lineage tracing and to disentangle cell autonomous and tissue-wide roles of candidate genes with single cell resolution. Given the relatively sparse labeling, depending on which of the 19 MADM chromosomes one chooses, the MADM approach represents the perfect opportunity for cell morphology analysis. Various MADM studies include reports of morphological anomalies and phenotypes in the central nervous system (CNS). MADM for any candidate gene can easily incorporate morphological analysis within the experimental workflow. Here, we describe the methods of morphological cell analysis which we developed in the course of diverse recent MADM studies. This chapter will specifically focus on methods to quantify aspects of the morphology of neurons and astrocytes within the CNS, but these methods can broadly be applied to any MADM-labeled cells throughout the entire organism. We will cover two analyses—soma volume and dendrite characterization—of physical characteristics of pyramidal neurons in the somatosensory cortex, and two analyses—volume and Sholl analysis—of astrocyte morphology.}, author = {Miranda, Osvaldo and Cheung, Giselle T and Hippenmeyer, Simon}, booktitle = {Neuronal Morphogenesis}, editor = {Toyooka, Kazuhito}, isbn = {9781071639689}, issn = {1940-6029}, pages = {283--299}, publisher = {Springer Nature}, title = {{Morphological Analysis of Neurons and Glia Using Mosaic Analysis with Double Markers}}, doi = {10.1007/978-1-0716-3969-6_19}, volume = {2831}, year = {2024}, } @unpublished{18688, abstract = {The human brain has remarkable computational power. It generates sophisticated behavioral sequences, stores engrams over an individual’s lifetime, and produces higher cognitive functions up to the level of consciousness. However, so little of our neuroscience knowledge covers the human brain, and it remains unknown whether this organ is truly unique, or is a scaled version of the extensively studied rodent brain. To address this fundamental question, we determined the cellular, synaptic, and connectivity rules of the hippocampal CA3 recurrent circuit using multicellular patch clamp-recording. This circuit is the largest autoassociative network in the brain, and plays a key role in memory and higher-order computations such as pattern separation and pattern completion. We demonstrate that human hippocampal CA3 employs sparse connectivity, in stark contrast to neocortical recurrent networks. Connectivity sparsifies from rodents to humans, providing a circuit architecture that maximizes associational power. Unitary synaptic events at human CA3–CA3 synapses showed both distinct species-specific and circuit-dependent properties, with high reliability, unique amplitude precision, and long integration times. We also identify differential scaling rules between hippocampal pathways from rodents to humans, with a moderate increase in the convergence of CA3 inputs per cell, but a marked increase in human mossy fiber innervation. Anatomically guided full-scale modeling suggests that the human brain’s sparse connectivity, expanded neuronal number, and reliable synaptic signaling combine to enhance the associative memory storage capacity of CA3. Together, our results reveal unique rules of connectivity and synaptic signaling in the human hippocampus, demonstrating the absolute necessity of human brain research and beginning to unravel the remarkable performance of our autoassociative memory circuits.}, author = {Watson, Jake F. and Vargas-Barroso, Victor and Morse-Mora, Rebecca J. and Navas-Olive, Andrea and Tavakoli, Mojtaba and Danzl, Johann G and Tomschik, Matthias and Rössler, Karl and Jonas, Peter M}, booktitle = {bioRxiv}, title = {{Human hippocampal CA3 uses specific functional connectivity rules for efficient associative memory}}, doi = {10.1101/2024.05.02.592169}, year = {2024}, } @article{14257, abstract = {Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here we developed Comprehensive Analysis of Tissues across Scales (CATS), a technology to densely map brain tissue architecture from millimeter regional to nanometer synaptic scales in diverse chemically fixed brain preparations, including rodent and human. CATS uses fixation-compatible extracellular labeling and optical imaging, including stimulated emission depletion or expansion microscopy, to comprehensively delineate cellular structures. It enables three-dimensional reconstruction of single synapses and mapping of synaptic connectivity by identification and analysis of putative synaptic cleft regions. Applying CATS to the mouse hippocampal mossy fiber circuitry, we reconstructed and quantified the synaptic input and output structure of identified neurons. We furthermore demonstrate applicability to clinically derived human tissue samples, including formalin-fixed paraffin-embedded routine diagnostic specimens, for visualizing the cellular architecture of brain tissue in health and disease.}, author = {Michalska, Julia M and Lyudchik, Julia and Velicky, Philipp and Korinkova, Hana and Watson, Jake and Cenameri, Alban and Sommer, Christoph M and Amberg, Nicole and Venturino, Alessandro and Roessler, Karl and Czech, Thomas and Höftberger, Romana and Siegert, Sandra and Novarino, Gaia and Jonas, Peter M and Danzl, Johann G}, issn = {1546-1696}, journal = {Nature Biotechnology}, pages = {1051--1064}, publisher = {Springer Nature}, title = {{Imaging brain tissue architecture across millimeter to nanometer scales}}, doi = {10.1038/s41587-023-01911-8}, volume = {42}, year = {2024}, } @phdthesis{18674, abstract = {Mapping the complex and dense arrangement of cells and their connectivity in brain tissue requires volumetric imaging at nanoscale spatial resolution. While light microscopy excels at visualizing specific molecules and individual cells, achieving dense, synapse-level circuit reconstruction has not been possible with any light microscopy technique. Thus, the goal of my work was to develop image and data analysis pipelines for brain tissue visualization and reconstruction with light microscopy. To achieve dense circuit reconstruction with single-synapse resolution, I developed both conventional and deep-learning-based synapse detection algorithms, as well as connectivity analysis pipelines that integrate synapse detection with volumetric segmentation of brain tissue.}, author = {Lyudchik, Julia}, isbn = { 978-3-99078-051-0}, issn = {2663-337X}, pages = {217}, publisher = {Institute of Science and Technology Austria}, title = {{Image analysis for brain tissue reconstruction with super-resolution light microscopy}}, doi = {10.15479/at:ista:18674}, year = {2024}, } @article{18481, abstract = {A tight regulation of morphogen production is key for morphogen gradient formation and thereby for reproducible and organised organ development. Although many genetic interactions involved in the establishment of morphogen production domains are known, the biophysical mechanisms of morphogen source formation are poorly understood. Here we addressed this by focusing on the morphogen Sonic hedgehog (Shh) in the vertebrate neural tube. Shh is produced by the adjacently located notochord and by the floor plate of the neural tube. Using a data-constrained computational screen, we identified different possible mechanisms by which floor plate formation can occur, only one of which is consistent with experimental data. In this mechanism, the floor plate is established rapidly in response to Shh from the notochord and the dynamics of regulatory interactions within the neural tube. In this process, uniform activators and Shh-dependent repressors are key for establishing the floor plate size. Subsequently, the floor plate becomes insensitive to Shh and increases in size due to tissue growth, leading to scaling of the floor plate with neural tube size. In turn, this results in scaling of the Shh amplitude with tissue growth. Thus, this mechanism ensures a separation of time scales in floor plate formation, so that the floor plate domain becomes growth-dependent after an initial rapid establishment phase. Our study raises the possibility that the time scale separation between specification and growth might be a common strategy for scaling the morphogen gradient amplitude in growing organs. The model that we developed provides a new opportunity for quantitative studies of morphogen source formation in growing tissues.}, author = {Ho, Richard D.J.G. and Kishi, Kasumi and Majka, Maciej and Kicheva, Anna and Zagórski, Marcin P}, issn = {1553-7358}, journal = {PLoS Computational Biology}, publisher = {Public Library of Science}, title = {{Dynamics of morphogen source formation in a growing tissue}}, doi = {10.1371/journal.pcbi.1012508}, volume = {20}, year = {2024}, } @article{18902, author = {Zagorski, Marcin and Brandenberg, Nathalie and Lutolf, Matthias and Tkačik, Gašper and Bollenbach, Mark Tobias and Briscoe, James and Kicheva, Anna}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Assessing the precision of morphogen gradients in neural tube development}}, doi = {10.1038/s41467-024-45148-8}, volume = {15}, year = {2024}, } @phdthesis{17133, abstract = {An ideal quantum computer relies on qubits capable of performing fast gate operations and maintaining strong interconnections while preserving their quantum coherence. Since the inception of experimental eforts toward building a quantum computer, the community has faced challenges in engineering such a system. Among the various methods of implementing a quantum computer, superconducting qubits have shown fast gates close to tens of nanoseconds, with the state-of-the-art reaching a coherence of a few milliseconds. However, achieving simultaneously long lifetimes with fast qubit operations poses an inherent paradox. Qubits with high coherence require isolation from the environment, while fast operation necessitates strong coupling of the qubit. This thesis approaches this issue by proposing the idea of engineering superconducting qubits capable of transitioning between operating in a protected regime, where the qubit is completely isolated from the environment, and coupling to the communication channels as needed. In this direction, we use the geometric superinductor to scan the parameter space of rf-SQUID devices, searching for a regime where we can take the qubit protection to its extreme. This leads us to the inductively shunted transmon (IST) regime, characterized by EJ /EC ≫ 1 and EJ /EL ≫ 1, where the circuit potential exhibits a double well with a large barrier separating the local ground states of each quantum well. In this regime, although it is anticipated that the two quantum wells would be isolated from each other, we observe single fuxon tunneling between them. The interplay of the cavity photons and the fuxon transition forms a rich physical system, containing resonance conditions that allow the preparation of the fuxon ground or excited states. This enables us to study the relaxation rate of such transition and show that it can be as large as 3.6 hours. Dynamically controlling the barrier height between the two quantum wells allows for controllable coupling, which scales exponentially, for a qubit encoded in two fuxon states. The 0-π qubit is one of the very few known superconducting circuit types that ofers exponential protection from both relaxation and dephasing simultaneously. However, this qubit is not exempt from the fact that such protection comes at the expense of complex readout and control. In this thesis, we propose a way to controllably break the circuit symmetry, the key reason for the protection, to momentarily restore the ability to control and manipulate the qubit. An asymmetry in capacitances and inductances in the 0-π circuit is detrimental since they lead to coupling of the protected state to the thermally occupied parasitic mode of the circuit. However, here we try to exploit a controlled asymmetry in Josephson energies and show that this can be used as a tunable coupler between the protected states. In the future, this should allow to perform gate operations by dynamically controlling the asymmetry instead of driving the protected transition with microwave pulses. Therefore, we believe that the proposed method can make the use of protected qubits more practical in experimental realizations of quantum computing.}, author = {Hassani, Farid}, isbn = {978-3-99078-040-4}, issn = {2663-337X}, keywords = {Quantum information, Qubits, Superconducting devices}, pages = {161}, publisher = {Institute of Science and Technology Austria}, title = {{Superconducting qubits capable of dynamic switching between protected and high-speed control regimes}}, doi = {10.15479/at:ista:17133}, year = {2024}, } @article{15362, abstract = {Constitutional heterozygous pathogenic variants in the exonuclease domain of POLE and POLD1, which affect the proofreading activity of the corresponding polymerases, cause a cancer predisposition syndrome characterized by increased risk of gastrointestinal polyposis, colorectal cancer, endometrial cancer and other tumor types. The generally accepted explanation for the connection between the disruption of the proofreading activity of polymerases epsilon and delta and cancer development is through an increase in the somatic mutation rate. Here we studied an extended family with multiple members heterozygous for the pathogenic POLD1 variant c.1421T>C p.(Leu474Pro), which segregates with the polyposis and cancer phenotypes. Through the analysis of mutational patterns of patient-derived fibroblasts colonies and de novo mutations obtained by parent-offspring comparisons, we concluded that heterozygous POLD1 L474P just subtly increases the somatic and germline mutation burden. In contrast, tumors developed in individuals with a heterozygous mutation in the exonuclease domain of POLD1, including L474P, have an extremely high mutation rate (>100 mut/Mb) associated with signature SBS10d. We solved this contradiction through the observation that tumorigenesis involves somatic inactivation of the wildtype POLD1 allele. These results imply that exonuclease deficiency of polymerase delta has a recessive effect on mutation rate.}, author = {Andrianova, Maria A. and Seplyarskiy, Vladimir B. and Terradas, Mariona and Sánchez-Heras, Ana Beatriz and Mur, Pilar and Soto, José Luis and Aiza, Gemma and Borràs, Emma and Kondrashov, Fyodor and Kondrashov, Alexey S. and Bazykin, Georgii A. and Valle, Laura}, issn = {1476-5438}, journal = {European Journal of Human Genetics}, pages = {837--845}, publisher = {Springer Nature}, title = {{Discovery of recessive effect of human polymerase δ proofreading deficiency through mutational analysis of POLD1-mutated normal and cancer cells}}, doi = {10.1038/s41431-024-01598-8}, volume = {32}, year = {2024}, } @phdthesis{18135, abstract = {This thesis consists of two separate parts. In the first part we consider a dilute Fermi gas interacting through a repulsive interaction in dimensions $d=1,2,3$. Our focus is mostly on the physically most relevant dimension $d=3$ and the setting of a spin-polarized (equivalently spinless) gas, where the Pauli exclusion principle plays a key role. We show that, at zero temperature, the ground state energy density of the interacting spin-polarized gas differs (to leading order) from that of the free (i.e. non-interacting) gas by a term of order $a_p^d\rho^{2+2/d}$ with $a_p$ the $p$-wave scattering length of the repulsive interaction and $\rho$ the density. Further, we extend this to positive temperature and show that the pressure of an interacting spin-polarized gas differs from that of the free gas by a now temperature dependent term, again of order $a_p^d\rho^{2+2/d}$. Lastly, we consider the setting of a spin-$\frac{1}{2}$ Fermi gas in $d=3$ dimensions and show that here, as an upper bound, the ground state energy density differs from that of the free system by a term of order $a_s \rho^2$ with an error smaller than $a_s \rho^2 (a_s\rho^{1/3})^{1-\eps}$ for any $\eps > 0$, where $a_s$ is the $s$-wave scattering length of the repulsive interaction. These asymptotic formulas complement the similar formulas in the literature for the dilute Bose and spin-$\frac{1}{2}$ Fermi gas, where the ground state energies or pressures differ from that of the corresponding free systems by a term of order $a_s \rho^2$ in dimension $d=3$. In the spin-polarized setting, the corrections, of order $a_p^3\rho^{8/3}$ in dimension $d=3$, are thus much smaller and requires a more delicate analysis. In the second part of the thesis we consider the Bardeen--Cooper--Schrieffer (BCS) theory of superconductivity and in particular its associated critical temperature and energy gap. We prove that the ratio of the zero-temperature energy gap and critical temperature $\Xi(T=0)/T_c$ approaches a universal constant $\pi e^{-\gamma}\approx 1.76$ in both the limit of high density in dimension $d=3$ and in the limit of weak coupling in dimensions $d=1,2$. This complements the proofs in the literature of this universal behaviour in the limit of weak coupling or low density in dimension $d=3$. Secondly, we prove that the ratio of the energy gap at positive temperature and critical temperature $\Xi(T)/T_c$ approaches a universal function of the relative temperature $T/T_c$ in the limit of weak coupling in dimensions $d=1,2,3$.}, author = {Lauritsen, Asbjørn Bækgaard}, isbn = {978-3-99078-042-8}, issn = {2663-337X}, pages = {353}, publisher = {Institute of Science and Technology Austria}, title = {{Energies of dilute Fermi gases and universalities in BCS theory}}, doi = {10.15479/at:ista:18135}, year = {2024}, } @article{14931, abstract = {We prove an upper bound on the ground state energy of the dilute spin-polarized Fermi gas capturing the leading correction to the kinetic energy resulting from repulsive interactions. One of the main ingredients in the proof is a rigorous implementation of the fermionic cluster expansion of Gaudin et al. (1971) [15].}, author = {Lauritsen, Asbjørn Bækgaard and Seiringer, Robert}, issn = {1096-0783}, journal = {Journal of Functional Analysis}, number = {7}, publisher = {Elsevier}, title = {{Ground state energy of the dilute spin-polarized Fermi gas: Upper bound via cluster expansion}}, doi = {10.1016/j.jfa.2024.110320}, volume = {286}, year = {2024}, }