@article{14343,
  abstract     = {The total energy of an eigenstate in a composite quantum system tends to be distributed equally among its constituents. We identify the quantum fluctuation around this equipartition principle in the simplest disordered quantum system consisting of linear combinations of Wigner matrices. As our main ingredient, we prove the Eigenstate Thermalisation Hypothesis and Gaussian fluctuation for general quadratic forms of the bulk eigenvectors of Wigner matrices with an arbitrary deformation.},
  author       = {Cipolloni, Giorgio and Erdös, László and Henheik, Sven Joscha and Kolupaiev, Oleksii},
  issn         = {2050-5094},
  journal      = {Forum of Mathematics, Sigma},
  publisher    = {Cambridge University Press},
  title        = {{Gaussian fluctuations in the equipartition principle for Wigner matrices}},
  doi          = {10.1017/fms.2023.70},
  volume       = {11},
  year         = {2023},
}

@inproceedings{17378,
  abstract     = {Generative Pre-trained Transformer models, known as GPT or OPT, set themselves apart through breakthrough performance across complex language modelling tasks, but also by their extremely high computational and storage costs. Specifically, due to their massive size, even inference for large, highly-accurate GPT models may require multiple performant GPUs, which limits the usability of such models. While there is emerging work on relieving this pressure via model compression, the applicability and performance of existing compression techniques is limited by the scale and complexity of GPT models. In this paper, we address this challenge, and propose OPTQ, a new one-shot weight quantization method based on approximate second-order information, that is both highly-accurate and highly-efficient. Specifically, OPTQ can quantize GPT models with 175 billion parameters in approximately four GPU hours, reducing the bitwidth down to 3 or 4 bits per weight, with negligible accuracy degradation relative to the uncompressed baseline. Our method more than doubles the compression gains relative to previously-proposed one-shot quantization methods, preserving accuracy, allowing us for the first time to execute an 175 billion-parameter model inside a single GPU for generative inference. Moreover, we also show that our method can still provide reasonable accuracy in the extreme quantization regime, in which weights are quantized to 2-bit or even ternary quantization levels. We show experimentally that these improvements can be leveraged for end-to-end inference speedups over FP16, of around 3.25x when using high-end GPUs (NVIDIA A100) and 4.5x when using more cost-effective ones (NVIDIA A6000). The implementation is available at https://github.com/IST-DASLab/gptq.},
  author       = {Frantar, Elias and Ashkboos, Saleh and Hoefler, Torsten and Alistarh, Dan-Adrian},
  booktitle    = {11th International Conference on Learning Representations },
  location     = {Kigali, Rwanda},
  publisher    = {International Conference on Learning Representations},
  title        = {{OPTQ: Accurate post-training quantization for generative pre-trained transformers}},
  year         = {2023},
}

@inproceedings{14458,
  abstract     = {We show for the first time that large-scale generative pretrained transformer (GPT) family models can be pruned to at least 50% sparsity in one-shot, without any retraining, at minimal loss of accuracy. This is achieved via a new pruning method called SparseGPT, specifically designed to work efficiently and accurately on massive GPT-family models. We can execute SparseGPT on the largest available open-source models, OPT-175B and BLOOM-176B, in under 4.5 hours, and can reach 60% unstructured sparsity with negligible increase in perplexity: remarkably, more than 100 billion weights from these models can be ignored at inference time. SparseGPT generalizes to semi-structured (2:4 and 4:8) patterns, and is compatible with weight quantization approaches. The code is available at: https://github.com/IST-DASLab/sparsegpt.},
  author       = {Frantar, Elias and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 40th International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Honolulu, Hawaii, HI, United States},
  pages        = {10323--10337},
  publisher    = {ML Research Press},
  title        = {{SparseGPT: Massive language models can be accurately pruned in one-shot}},
  volume       = {202},
  year         = {2023},
}

@unpublished{18294,
  abstract     = {Using a two-dimensional version of the delta method, we establish an asymptotic formula for the number of rational points of bounded height on non-singular complete intersections of cubic and quadric hypersurfaces of dimension at least 23 over Fq(t), provided cha(Fq)>3. Under the same hypotheses, we also verify weak approximation.},
  author       = {Glas, Jakob},
  booktitle    = {arXiv},
  title        = {{Complete intersections of cubic and quadric hypersurfaces over Fq(t)}},
  doi          = {10.48550/arXiv.2306.02718},
  year         = {2023},
}

@unpublished{14732,
  abstract     = {Fragmented landscapes pose a significant threat to the persistence of species as they are highly susceptible to heightened risk of extinction due to the combined effects of genetic and demographic factors such as genetic drift and demographic stochasticity. This paper explores the intricate interplay between genetic load and extinction risk within metapopulations with a focus on understanding the impact of eco-evolutionary feedback mechanisms. We distinguish between two models of selection: soft selection, characterised by subpopulations maintaining carrying capacity despite load, and hard selection, where load can significantly affect population size. Within the soft selection framework, we investigate the impact of gene flow on genetic load at a single locus, while also considering the effect of selection strength and dominance coefficient. We subsequently build on this to examine how gene flow influences both population size and load under hard selection as well as identify critical thresholds for metapopulation persistence. Our analysis employs the diffusion, semi-deterministic and effective migration approximations. Our findings reveal that under soft selection, even modest levels of migration can significantly alleviate the burden of load. In sharp contrast, with hard selection, a much higher degree of gene flow is required to mitigate load and prevent the collapse of the metapopulation. Overall, this study sheds light into the crucial role migration plays in shaping the dynamics of genetic load and extinction risk in fragmented landscapes, offering valuable insights for conservation strategies and the preservation of diversity in a changing world.},
  author       = {Olusanya, Oluwafunmilola O and Khudiakova, Kseniia and Sachdeva, Himani},
  booktitle    = {bioRxiv},
  title        = {{Genetic load, eco-evolutionary feedback and extinction in a metapopulation}},
  doi          = {10.1101/2023.12.02.569702},
  year         = {2023},
}

@article{12334,
  abstract     = {Regulation of the Arp2/3 complex is required for productive nucleation of branched actin networks. An emerging aspect of regulation is the incorporation of subunit isoforms into the Arp2/3 complex. Specifically, both ArpC5 subunit isoforms, ArpC5 and ArpC5L, have been reported to fine-tune nucleation activity and branch junction stability. We have combined reverse genetics and cellular structural biology to describe how ArpC5 and ArpC5L differentially affect cell migration. Both define the structural stability of ArpC1 in branch junctions and, in turn, by determining protrusion characteristics, affect protein dynamics and actin network ultrastructure. ArpC5 isoforms also affect the positioning of members of the Ena/Vasodilator-stimulated phosphoprotein (VASP) family of actin filament elongators, which mediate ArpC5 isoform–specific effects on the actin assembly level. Our results suggest that ArpC5 and Ena/VASP proteins are part of a signaling pathway enhancing cell migration.</jats:p>},
  author       = {Fäßler, Florian and Javoor, Manjunath and Datler, Julia and Döring, Hermann and Hofer, Florian and Dimchev, Georgi A and Hodirnau, Victor-Valentin and Faix, Jan and Rottner, Klemens and Schur, Florian KM},
  issn         = {2375-2548},
  journal      = {Science Advances},
  keywords     = {Multidisciplinary},
  number       = {3},
  publisher    = {American Association for the Advancement of Science},
  title        = {{ArpC5 isoforms regulate Arp2/3 complex–dependent protrusion through differential Ena/VASP positioning}},
  doi          = {10.1126/sciadv.add6495},
  volume       = {9},
  year         = {2023},
}

@unpublished{17351,
  abstract     = {Contractive coupling rates have been recently introduced by Conforti as a
tool to establish convex Sobolev inequalities (including modified log-Sobolev
and Poincar\'{e} inequality) for some classes of Markov chains. In this work,
we show how contractive coupling rates can also be used to prove stronger
inequalities, in the form of curvature lower bounds for Markov chains and
geodesic convexity of entropic functionals. We illustrate this in several
examples discussed by Conforti, where in particular, after appropriately
choosing a parameter function, we establish positive curvature in the entropic
and (discrete) Bakry--\'{E}mery sense. In addition, we recall and give
straightforward generalizations of some notions of coarse Ricci curvature, and
we discuss some of their properties and relations with the concepts of
couplings and coupling rates: as an application, we show exponential
contraction of the $p$-Wasserstein distance for the heat flow in the
aforementioned examples.},
  author       = {Pedrotti, Francesco},
  booktitle    = {arXiv},
  title        = {{Contractive coupling rates and curvature lower bounds for Markov chains}},
  doi          = {10.48550/arXiv.2308.00516},
  year         = {2023},
}

@inproceedings{14461,
  abstract     = {Communication-reduction techniques are a popular way to improve scalability in data-parallel training of deep neural networks (DNNs). The recent emergence of large language models such as GPT has created the need for new approaches to exploit data-parallelism. Among these, fully-sharded data parallel (FSDP) training is highly popular, yet it still encounters scalability bottlenecks. One reason is that applying compression techniques to FSDP is challenging: as the vast majority of the communication involves the model’s weights, direct compression alters convergence and leads to accuracy loss. We present QSDP, a variant of FSDP which supports both gradient and weight quantization with theoretical guarantees, is simple to implement and has essentially no overheads. To derive QSDP we prove that a natural modification of SGD achieves convergence even when we only maintain quantized weights, and thus the domain over which we train consists of quantized points and is, therefore, highly non-convex. We validate this approach by training GPT-family models with up to 1.3 billion parameters on a multi-node cluster. Experiments show that QSDP preserves model accuracy, while completely removing the communication bottlenecks of FSDP, providing end-to-end speedups of up to 2.2x.},
  author       = {Markov, Ilia and Vladu, Adrian and Guo, Qi and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 40th International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Honolulu, Hawaii, HI, United States},
  pages        = {24020--24044},
  publisher    = {ML Research Press},
  title        = {{Quantized distributed training of large models with convergence guarantees}},
  volume       = {202},
  year         = {2023},
}

@unpublished{17174,
  abstract     = {We prove that a class of weakly perturbed Hamiltonians of the form $H_λ= H_0 + λW$, with $W$ being a Wigner matrix, exhibits prethermalization. That is, the time evolution generated by $H_λ$ relaxes to its ultimate thermal state via an intermediate prethermal state with a lifetime of order $λ^{-2}$. Moreover, we obtain a general relaxation formula, expressing the perturbed dynamics via the unperturbed dynamics and the ultimate thermal state. The proof relies on a two-resolvent law for the deformed Wigner matrix $H_λ$.},
  author       = {Erdös, László and Henheik, Sven Joscha and Reker, Jana and Riabov, Volodymyr},
  booktitle    = {arXiv},
  title        = {{Prethermalization for deformed Wigner Matrices}},
  doi          = {10.48550/arXiv.2310.06677},
  year         = {2023},
}

@unpublished{17173,
  abstract     = {Consider the random variable $\mathrm{Tr}( f_1(W)A_1\dots f_k(W)A_k)$ where $W$ is an $N\times N$ Hermitian Wigner matrix, $k\in\mathbb{N}$, and choose (possibly $N$-dependent) regular functions $f_1,\dots, f_k$ as well as bounded deterministic matrices $A_1,\dots,A_k$. We give a functional central limit theorem showing that the fluctuations around the expectation are Gaussian. Moreover, we determine the limiting covariance structure and give explicit error bounds in terms of the scaling of $f_1,\dots,f_k$ and the number of traceless matrices among $A_1,\dots,A_k$, thus extending the results of [Cipolloni, Erdős, Schröder 2023] to products of arbitrary length $k\geq2$. As an application, we consider the fluctuation of $\mathrm{Tr}(\mathrm{e}^{\mathrm{i} tW}A_1\mathrm{e}^{-\mathrm{i} tW}A_2)$ around its thermal value $\mathrm{Tr}(A_1)\mathrm{Tr}(A_2)$ when $t$ is large and give an explicit formula for the variance.},
  author       = {Reker, Jana},
  booktitle    = {arXiv},
  title        = {{Multi-point functional central limit theorem for Wigner Matrices}},
  doi          = {10.48550/arXiv.2307.11028},
  year         = {2023},
}

@phdthesis{12716,
  abstract     = {The process of detecting and evaluating sensory information to guide behaviour is termed perceptual decision-making (PDM), and is critical for the ability of an organism to interact with its external world. Individuals with autism, a neurodevelopmental condition primarily characterised by social and communication difficulties, frequently exhibit altered sensory processing and PDM difficulties are widely reported. Recent technological advancements have pushed forward our understanding of the genetic changes accompanying this condition, however our understanding of how these mutations affect the function of specific neuronal circuits and bring about the corresponding behavioural changes remains limited. Here, we use an innate PDM task, the looming avoidance response (LAR) paradigm, to identify a convergent behavioural abnormality across three molecularly distinct genetic mouse models of autism (Cul3, Setd5 and Ptchd1). Although mutant mice can rapidly detect threatening visual stimuli, their responses are consistently delayed, requiring longer to initiate an appropriate response than their wild-type siblings. Mutant animals show abnormal adaptation in both their stimulus- evoked escape responses and exploratory dynamics following repeated stimulus presentations. Similarly delayed behavioural responses are observed in wild-type animals when faced with more ambiguous threats, suggesting the mutant phenotype could arise from a dysfunction in the flexible control of this PDM process.
Our knowledge of the core neuronal circuitry mediating the LAR facilitated a detailed dissection of the neuronal mechanisms underlying the behavioural impairment. In vivo extracellular recording revealed that visual responses were unaffected within a key brain region for the rapid processing of visual threats, the superior colliculus (SC), indicating that the behavioural delay was unlikely to originate from sensory impairments. Delayed behavioural responses were recapitulated in the Setd5 model following optogenetic stimulation of the excitatory output neurons of the SC, which are known to mediate escape initiation through the activation of cells in the underlying dorsal periaqueductal grey (dPAG). In vitro patch-clamp recordings of dPAG cells uncovered a stark hypoexcitability phenotype in two out of the three genetic models investigated (Setd5 and Ptchd1), that in Setd5, is mediated by the misregulation of voltage-gated potassium channels. Overall, our results show that the ability to use visual information to drive efficient escape responses is impaired in three diverse genetic mouse models of autism and that, in one of the models studied, this behavioural delay likely originates from differences in the intrinsic excitability of a key subcortical node, the dPAG. Furthermore, this work showcases the use of an innate behavioural paradigm to mechanistically dissect PDM processes in autism.},
  author       = {Burnett, Laura},
  issn         = {2663-337X},
  pages        = {178},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{To flee, or not to flee? Using innate defensive behaviours to investigate rapid perceptual decision-making through subcortical circuits in mouse models of autism}},
  doi          = {10.15479/at:ista:12716},
  year         = {2023},
}

@phdthesis{14547,
  abstract     = {Superconductor-semiconductor heterostructures currently capture a significant amount of research interest and they serve as the physical platform in many proposals towards topological quantum computation.
Despite being under extensive investigations, historically using transport techniques, the basic properties of the interface between the superconductor and the semiconductor remain to be understood.

In this thesis, two separate studies on the Al-InAs heterostructures are reported with the first focusing on the physics of the material motivated by the emergence of a new phase, the Bogoliubov-Fermi surface. 
The second focuses on a technological application, a gate-tunable Josephson parametric amplifier.

In the first study, we investigate the hypothesized unconventional nature of the induced superconductivity at the interface between the Al thin film and the InAs quantum well.
We embed a two-dimensional Al-InAs hybrid system in a resonant microwave circuit allowing measurements of change in inductance.
The behaviour of the resonance in a range of temperature and in-plane magnetic field has been studied and compared with the theory of conventional s-wave superconductor and a two-component theory that includes both contribution of the $s$-wave pairing in Al and the intraband $p \pm ip$ pairing in InAs.
Measuring the temperature dependence of resonant frequency, no discrepancy is found between data and the conventional theory.
We observe the breakdown of superconductivity due to an applied magnetic field which contradicts the conventional theory.
In contrast, the data can be captured quantitatively by fitting to a two-component model.
We find the evidence of the intraband $p \pm ip$ pairing in the InAs and the emergence of the Bogoliubov-Fermi surfaces due to magnetic field with the characteristic value $B^* = 0.33~\mathrm{T}$.
From the fits, the sheet resistance of Al, the carrier density and mobility in InAs are determined.
By systematically studying the anisotropy of the circuit response, we find weak anisotropy for $B < B^*$ and increasingly strong anisotropy for $B > B^*$ resulting in a pronounced two-lobe structure in polar plot of frequency versus field angle.
Strong resemblance between the field dependence of dissipation and superfluid density hints at a hidden signature of the Bogoliubov-Fermi surface that is burried in the dissipation data.

In the second study, we realize a parametric amplifier with a Josephson field effect transistor as the active element.
The device's modest construction consists of a gated SNS weak link embedded at the center of a coplanar waveguide resonator.
By applying a gate voltage, the resonant frequency is field-effect tunable over a range of 2 GHz.
Modelling the JoFET minimally as a parallel RL circuit, the dissipation introduced by the JoFET can be quantitatively related to the gate voltage.
We observed gate-tunable Kerr nonlinearity qualitatively in line with expectation.
The JoFET amplifier has 20 dB of gain, 4 MHz of instantaneous bandwidth, and a 1dB compression point of -125.5 dBm when operated at a fixed resonant frequency.
In general, the signal-to-noise ratio is improved by 5-7 dB when the JoFET amplifier is activated compared.
The noise of the measurement chain and insertion loss of relevant circuit elements are calibrated to determine the expected and the real noise performance of the JoFET amplifier.
As a quantification of the noise performance, the measured total input-referred noise of the JoFET amplifier is in good agreement with the estimated expectation which takes device loss into account.
We found that the noise performance of the device reported in this document approaches one photon of total input-referred added noise which is the quantum limit imposed in nondegenerate parametric amplifier.},
  author       = {Phan, Duc T},
  issn         = {2663-337X},
  keywords     = {superconductor-semiconductor, superconductivity, Al, InAs, p-wave, superconductivity, JPA, microwave},
  pages        = {80},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Resonant microwave spectroscopy of Al-InAs}},
  doi          = {10.15479/14547},
  year         = {2023},
}

@phdthesis{14058,
  abstract     = {Females and males across species are subject to divergent selective pressures arising
from di↵erent reproductive interests and ecological niches. This often translates into a
intricate array of sex-specific natural and sexual selection on traits that have a shared
genetic basis between both sexes, causing a genetic sexual conflict. The resolution of
this conflict mostly relies on the evolution of sex-specific expression of the shared genes,
leading to phenotypic sexual dimorphism. Such sex-specific gene expression is thought
to evolve via modifications of the genetic networks ultimately linked to sex-determining
transcription factors. Although much empirical and theoretical evidence supports this
standard picture of the molecular basis of sexual conflict resolution, there still are a
few open questions regarding the complex array of selective forces driving phenotypic
di↵erentiation between the sexes, as well as the molecular mechanisms underlying sexspecific adaptation. I address some of these open questions in my PhD thesis.
First, how do patterns of phenotypic sexual dimorphism vary within populations,
as a response to the temporal and spatial changes in sex-specific selective forces? To
tackle this question, I analyze the patterns of sex-specific phenotypic variation along
three life stages and across populations spanning the whole geographical range of Rumex
hastatulus, a wind-pollinated angiosperm, in the first Chapter of the thesis.
Second, how do gene expression patterns lead to phenotypic dimorphism, and what
are the molecular mechanisms underlying the observed transcriptomic variation? I
address this question by examining the sex- and tissue-specific expression variation in
newly-generated datasets of sex-specific expression in heads and gonads of Drosophila
melanogaster. I additionally used two complementary approaches for the study of the
genetic basis of sex di↵erences in gene expression in the second and third Chapters of
the thesis.
Third, how does intersex correlation, thought to be one of the main aspects constraining the ability for the two sexes to decouple, interact with the evolution of sexual
dimorphism? I develop models of sex-specific stabilizing selection, mutation and drift
to formalize common intuition regarding the patterns of covariation between intersex
correlation and sexual dimorphism in the fourth Chapter of the thesis.
Alltogether, the work described in this PhD thesis provides useful insights into the
links between genetic, transcriptomic and phenotypic layers of sex-specific variation,
and contributes to our general understanding of the dynamics of sexual dimorphism
evolution.},
  author       = {Puixeu Sala, Gemma},
  isbn         = {978-3-99078-035-0},
  issn         = {2663-337X},
  pages        = {230},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{The molecular basis of sexual dimorphism: Experimental and theoretical characterization of phenotypic, transcriptomic and genetic patterns of sex-specific adaptation}},
  doi          = {10.15479/at:ista:14058},
  year         = {2023},
}

@article{14077,
  abstract     = {The regulatory architecture of gene expression is known to differ substantially between sexes in Drosophila, but most studies performed
so far used whole-body data and only single crosses, which may have limited their scope to detect patterns that are robust across tissues
and biological replicates. Here, we use allele-specific gene expression of parental and reciprocal hybrid crosses between 6 Drosophila
melanogaster inbred lines to quantify cis- and trans-regulatory variation in heads and gonads of both sexes separately across 3 replicate
crosses. Our results suggest that female and male heads, as well as ovaries, have a similar regulatory architecture. On the other hand,
testes display more and substantially different cis-regulatory effects, suggesting that sex differences in the regulatory architecture that
have been previously observed may largely derive from testis-specific effects. We also examine the difference in cis-regulatory variation
of genes across different levels of sex bias in gonads and heads. Consistent with the idea that intersex correlations constrain expression
and can lead to sexual antagonism, we find more cis variation in unbiased and moderately biased genes in heads. In ovaries, reduced cis
variation is observed for male-biased genes, suggesting that cis variants acting on these genes in males do not lead to changes in ovary
expression. Finally, we examine the dominance patterns of gene expression and find that sex- and tissue-specific patterns of inheritance
as well as trans-regulatory variation are highly variable across biological crosses, although these were performed in highly controlled
experimental conditions. This highlights the importance of using various genetic backgrounds to infer generalizable patterns.},
  author       = {Puixeu Sala, Gemma and Macon, Ariana and Vicoso, Beatriz},
  issn         = {2160-1836},
  journal      = {G3: Genes, Genomes, Genetics},
  keywords     = {Genetics (clinical), Genetics, Molecular Biology},
  number       = {8},
  publisher    = {Oxford University Press},
  title        = {{Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster}},
  doi          = {10.1093/g3journal/jkad121},
  volume       = {13},
  year         = {2023},
}

@article{13264,
  abstract     = {We build a parametric amplifier with a Josephson field-effect transistor (JoFET) as the active element. The resonant frequency of the device is field-effect tunable over a range of 2 GHz. The JoFET amplifier has 20 dB of gain, 4 MHz of instantaneous bandwidth, and a 1-dB compression point of -125.5 dBm when operated at a fixed resonance frequency.

},
  author       = {Phan, Duc T and Falthansl-Scheinecker, Paul and Mishra, Umang and Strickland, W. M. and Langone, D. and Shabani, J. and Higginbotham, Andrew P},
  issn         = {2331-7019},
  journal      = {Physical Review Applied},
  number       = {6},
  publisher    = {American Physical Society},
  title        = {{Gate-tunable superconductor-semiconductor parametric amplifier}},
  doi          = {10.1103/PhysRevApplied.19.064032},
  volume       = {19},
  year         = {2023},
}

@misc{12933,
  abstract     = {Datasets of the publication "Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster".},
  author       = {Puixeu Sala, Gemma},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Data from: Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster}},
  doi          = {10.15479/AT:ISTA:12933},
  year         = {2023},
}

@phdthesis{12885,
  abstract     = {High-performance semiconductors rely upon precise control of heat and charge transport. This can be achieved by precisely engineering defects in polycrystalline solids. There are multiple approaches to preparing such polycrystalline semiconductors, and the transformation of solution-processed colloidal nanoparticles is appealing because colloidal nanoparticles combine low cost with structural and compositional tunability along with rich surface chemistry. However, the multiple processes from nanoparticle synthesis to the final bulk nanocomposites are very complex. They involve nanoparticle purification, post-synthetic modifications, and finally consolidation (thermal treatments and densification). All these properties dictate the final material’s composition and microstructure, ultimately affecting its functional properties. This thesis explores the synthesis, surface chemistry and consolidation of colloidal semiconductor nanoparticles into dense solids. In particular, the transformations that take place during these processes, and their effect on the material’s transport properties are evaluated. },
  author       = {Calcabrini, Mariano},
  isbn         = {978-3-99078-028-2},
  issn         = {2663-337X},
  pages        = {82},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Nanoparticle-based semiconductor solids: From synthesis to consolidation}},
  doi          = {10.15479/at:ista:12885},
  year         = {2023},
}

@phdthesis{12732,
  abstract     = {Nonergodic systems, whose out-of-equilibrium dynamics fail to thermalize, provide a fascinating research direction both for fundamental reasons and for application in state of the art quantum devices.
Going beyond the description of statistical mechanics, ergodicity breaking yields a new paradigm in quantum many-body physics, introducing novel phases of matter with no counterpart at equilibrium.
In this Thesis, we address different open questions in the field, focusing on disorder-induced many-body localization (MBL) and on weak ergodicity breaking in kinetically constrained models.
In particular, we contribute to the debate about transport in kinetically constrained models, studying the effect of $U(1)$ conservation and inversion-symmetry breaking in a family of quantum East models.
Using tensor network techniques, we analyze the dynamics of large MBL systems beyond the limit of exact numerical methods.
In this setting, we approach the debated topic of the coexistence of localized and thermal eigenstates separated by energy thresholds known as many-body mobility edges.
Inspired by recent experiments, our work further investigates the localization of a small bath induced by the coupling to a large localized chain, the so-called MBL proximity effect.

In the first Chapter, we introduce a family of particle-conserving kinetically constrained models, inspired by the quantum East model.
The system we study features strong inversion-symmetry breaking, due to the nature of the correlated hopping.
We show that these models host so-called quantum Hilbert space fragmentation, consisting of disconnected subsectors in an entangled basis, and further provide an analytical description of this phenomenon.
We further probe its effect on dynamics of simple product states, showing revivals in fidelity and local observalbes.
The study of dynamics within the largest subsector reveals an anomalous transient superdiffusive behavior crossing over to slow logarithmic dynamics at later times.
This work suggests that particle conserving constrained models with inversion-symmetry breaking realize new universality classes of dynamics and invite their further theoretical and experimental studies.

Next, we use kinetic constraints and disorder to design a model with many-body mobility edges in particle density.
This feature allows to study the dynamics of localized and thermal states in large systems beyond the limitations of previous studies.
The time-evolution shows typical signatures of localization at small densities, replaced by thermal behavior at larger densities.
Our results provide evidence in favor of the stability of many-body mobility edges, which was recently challenged by a theoretical argument.
To support our findings, we probe the mechanism proposed as a cause of delocalization in many-body localized systems with mobility edges suggesting its ineffectiveness in the model studied.

In the last Chapter of this Thesis, we address the topic of many-body localization proximity effect.
We study a model inspired by recent experiments, featuring Anderson localized coupled to a small bath of free hard-core bosons.
The interaction among the two particle species results in non-trivial dynamics, which we probe using tensor network techniques.
Our simulations show convincing evidence of many-body localization proximity effect when the bath is composed by a single free particle and interactions are strong.
We furthter observe an anomalous entanglement dynamics, which we explain through a phenomenological theory.
Finally, we extract highly excited eigenstates of large systems, providing supplementary evidence in favor of our findings.},
  author       = {Brighi, Pietro},
  issn         = {2663-337X},
  pages        = {158},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Ergodicity breaking in disordered and kinetically constrained quantum many-body systems}},
  doi          = {10.15479/at:ista:12732},
  year         = {2023},
}

@phdthesis{12826,
  abstract     = {During navigation, animals can infer the structure of the environment by computing the optic flow cues elicited by their own movements, and subsequently use this information to instruct proper locomotor actions. These computations require a panoramic assessment of the visual environment in order to disambiguate similar sensory experiences that may require distinct behavioral responses. The estimation of the global motion patterns is therefore essential for successful navigation. Yet, our understanding of the algorithms and implementations that enable coherent panoramic visual perception remains scarce. Here I pursue this problem by dissecting the functional aspects of interneuronal communication in the lobula plate tangential cell network in Drosophila melanogaster. The results presented in the thesis demonstrate that the basis for effective interpretation of the optic flow in this circuit are stereotyped synaptic connections that mediate the formation of distinct subnetworks, each extracting a particular pattern of global motion. 
Firstly, I show that gap junctions are essential for a correct interpretation of binocular motion cues by horizontal motion-sensitive cells. HS cells form electrical synapses with contralateral H2 neurons that are involved in detecting yaw rotation and translation. I developed an FlpStop-mediated mutant of a gap junction protein ShakB that disrupts these electrical synapses. While the loss of electrical synapses does not affect the tuning of the direction selectivity in HS neurons, it severely alters their sensitivity to horizontal motion in the contralateral side. These physiological changes result in an inappropriate integration of binocular motion cues in walking animals. While wild-type flies form a binocular perception of visual motion by non-linear integration of monocular optic flow cues, the mutant flies sum the monocular inputs linearly. These results indicate that rather than averaging signals in neighboring neurons, gap-junctions operate in conjunction with chemical synapses to mediate complex non-linear optic flow computations.
Secondly, I show that stochastic manipulation of neuronal activity in the lobula plate tangential cell network is a powerful approach to study the neuronal implementation of optic flow-based navigation in flies. Tangential neurons form multiple subnetworks, each mediating course-stabilizing response to a particular global pattern of visual motion. Application of genetic mosaic techniques can provide sparse optogenetic activation of HS cells in numerous combinations. These distinct combinations of activated neurons drive an array of distinct behavioral responses, providing important insights into how visuomotor transformation is performed in the lobula plate tangential cell network. This approach can be complemented by stochastic silencing of tangential neurons, enabling direct assessment of the functional role of individual tangential neurons in the processing of specific visual motion patterns.
	Taken together, the findings presented in this thesis suggest that establishing specific activity patterns of tangential cells via stereotyped synaptic connectivity is a key to efficient optic flow-based navigation in Drosophila melanogaster.},
  author       = {Pokusaeva, Victoria},
  issn         = {2663-337X},
  pages        = {106},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Neural control of optic flow-based navigation in Drosophila melanogaster}},
  doi          = {10.15479/at:ista:12826},
  year         = {2023},
}

@phdthesis{13286,
  abstract     = {Semiconductor-superconductor hybrid systems are the harbour of many intriguing mesoscopic phenomena. This material combination leads to spatial variations of the superconducting properties, which gives rise to Andreev bound states (ABSs). Some of these states might exhibit remarkable properties that render them highly desirable for topological quantum computing. The most prominent and hunted of such states are Majorana zero modes (MZMs), quasiparticles equals to their own quasiparticles that they follow non-abelian statistics. In this thesis, we first introduce the general framework of such hybrid systems and, then, we unveil a series of mesoscopic phenomena that we discovered. Firstly, we show tunneling spectroscopy experiments on full-shell nanowires (NWs) showing that unwanted quantum-dot states coupled to superconductors (Yu-Shiba-Rusinov states) can mimic MZMs signatures. Then, we introduce a novel protocol which allowed the integration of tunneling spectroscopy with Coulomb spectroscopy within the same device. Employing this approach on both full-shell NWs and partial-shell NWs, we demonstrated that longitudinally confined states reveal charge transport phenomenology similar to the one expected for MZMs. These findings shed light on the intricate interplay between superconductivity and quantum confinement, which brought us to explore another material platform, i.e. a two-dimensional Germanium hole gas. After developing a robust way to induce superconductivity in such system, we showed how to engineer the proximity effect and we revealed a superconducting hard gap. Finally, we created a superconducting radio frequency driven ideal diode and a generator of non-sinusoidal current-phase relations. Our results open the path for the exploration of protected superconducting qubits and more complex hybrid devices in planar Germanium, like Kitaev chains and hybrid qubit devices.},
  author       = {Valentini, Marco},
  issn         = {2663-337X},
  pages        = {184},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Mesoscopic phenomena in hybrid semiconductor-superconductor nanodevices : From full-shell nanowires to two-dimensional hole gas in germanium}},
  doi          = {10.15479/at:ista:13286},
  year         = {2023},
}