@article{14320, abstract = {The development of two-dimensional materials has resulted in a diverse range of novel, high-quality compounds with increasing complexity. A key requirement for a comprehensive quantitative theory is the accurate determination of these materials' band structure parameters. However, this task is challenging due to the intricate band structures and the indirect nature of experimental probes. In this work, we introduce a general framework to derive band structure parameters from experimental data using deep neural networks. We applied our method to the penetration field capacitance measurement of trilayer graphene, an effective probe of its density of states. First, we demonstrate that a trained deep network gives accurate predictions for the penetration field capacitance as a function of tight-binding parameters. Next, we use the fast and accurate predictions from the trained network to automatically determine tight-binding parameters directly from experimental data, with extracted parameters being in a good agreement with values in the literature. We conclude by discussing potential applications of our method to other materials and experimental techniques beyond penetration field capacitance.}, author = {Henderson, Paul M and Ghazaryan, Areg and Zibrov, Alexander A. and Young, Andrea F. and Serbyn, Maksym}, issn = {2469-9969}, journal = {Physical Review B}, number = {12}, publisher = {American Physical Society}, title = {{Deep learning extraction of band structure parameters from density of states: A case study on trilayer graphene}}, doi = {10.1103/physrevb.108.125411}, volume = {108}, 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}, } @article{14334, abstract = {Quantum kinetically constrained models have recently attracted significant attention due to their anomalous dynamics and thermalization. In this work, we introduce a hitherto unexplored family of kinetically constrained models featuring conserved particle number and strong inversion-symmetry breaking due to facilitated hopping. We demonstrate that these models provide a generic example of so-called quantum Hilbert space fragmentation, that is manifested in disconnected sectors in the Hilbert space that are not apparent in the computational basis. Quantum Hilbert space fragmentation leads to an exponential in system size number of eigenstates with exactly zero entanglement entropy across several bipartite cuts. These eigenstates can be probed dynamically using quenches from simple initial product states. In addition, we study the particle spreading under unitary dynamics launched from the domain wall state, and find faster than diffusive dynamics at high particle densities, that crosses over into logarithmically slow relaxation at smaller densities. Using a classically simulable cellular automaton, we reproduce the logarithmic dynamics observed in the quantum case. Our work suggests that particle conserving constrained models with inversion symmetry breaking realize so far unexplored dynamical behavior and invite their further theoretical and experimental studies.}, author = {Brighi, Pietro and Ljubotina, Marko and Serbyn, Maksym}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {3}, publisher = {SciPost Foundation}, title = {{Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models}}, doi = {10.21468/scipostphys.15.3.093}, volume = {15}, year = {2023}, } @article{14321, abstract = {We demonstrate the possibility of a coupling between the magnetization direction of a ferromagnet and the tilting angle of adsorbed achiral molecules. To illustrate the mechanism of the coupling, we analyze a minimal Stoner model that includes Rashba spin–orbit coupling due to the electric field on the surface of the ferromagnet. The proposed mechanism allows us to study magnetic anisotropy of the system with an extended Stoner–Wohlfarth model and argue that adsorbed achiral molecules can change magnetocrystalline anisotropy of the substrate. Our research aims to motivate further experimental studies of the current-free chirality induced spin selectivity effect involving both enantiomers.}, author = {Al Hyder, Ragheed and Cappellaro, Alberto and Lemeshko, Mikhail and Volosniev, Artem}, issn = {1089-7690}, journal = {The Journal of Chemical Physics}, keywords = {Physical and Theoretical Chemistry, General Physics and Astronomy}, number = {10}, publisher = {AIP Publishing}, title = {{Achiral dipoles on a ferromagnet can affect its magnetization direction}}, doi = {10.1063/5.0165806}, volume = {159}, year = {2023}, } @article{14342, abstract = {We propose a simple method to measure nonlinear Kerr refractive index in mid-infrared frequency range that avoids using sophisticated infrared detectors. Our approach is based on using a near-infrared probe beam which interacts with a mid-IR beam via wavelength-non-degenerate cross-phase modulation (XPM). By carefully measuring XPM-induced spectral modifications in the probe beam and comparing the experimental data with simulation results, we extract the value for the non-degenerate Kerr index. Finally, in order to obtain the value of degenerate mid-IR Kerr index, we use the well-established two-band formalism of Sheik-Bahae et al., which is shown to become particularly simple in the limit of low frequencies. The proposed technique is complementary to the conventional techniques, such as z-scan, and has the advantage of not requiring any mid-infrared detectors.}, author = {Lorenc, Dusan and Alpichshev, Zhanybek}, issn = {0003-6951}, journal = {Applied Physics Letters}, number = {9}, publisher = {AIP Publishing}, title = {{Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam}}, doi = {10.1063/5.0161713}, volume = {123}, year = {2023}, } @article{14341, abstract = {Flows through pipes and channels are, in practice, almost always turbulent, and the multiscale eddying motion is responsible for a major part of the encountered friction losses and pumping costs1. Conversely, for pulsatile flows, in particular for aortic blood flow, turbulence levels remain low despite relatively large peak velocities. For aortic blood flow, high turbulence levels are intolerable as they would damage the shear-sensitive endothelial cell layer2,3,4,5. Here we show that turbulence in ordinary pipe flow is diminished if the flow is driven in a pulsatile mode that incorporates all the key features of the cardiac waveform. At Reynolds numbers comparable to those of aortic blood flow, turbulence is largely inhibited, whereas at much higher speeds, the turbulent drag is reduced by more than 25%. This specific operation mode is more efficient when compared with steady driving, which is the present situation for virtually all fluid transport processes ranging from heating circuits to water, gas and oil pipelines.}, author = {Scarselli, Davide and Lopez Alonso, Jose M and Varshney, Atul and Hof, Björn}, issn = {1476-4687}, journal = {Nature}, number = {7977}, pages = {71--74}, publisher = {Springer Nature}, title = {{Turbulence suppression by cardiac-cycle-inspired driving of pipe flow}}, doi = {10.1038/s41586-023-06399-5}, volume = {621}, year = {2023}, } @article{14368, abstract = {Purpose: Biallelic variants in TARS2, encoding the mitochondrial threonyl-tRNA-synthetase, have been reported in a small group of individuals displaying a neurodevelopmental phenotype but with limited neuroradiological data and insufficient evidence for causality of the variants. Methods: Exome or genome sequencing was carried out in 15 families. Clinical and neuroradiological evaluation was performed for all affected individuals, including review of 10 previously reported individuals. The pathogenicity of TARS2 variants was evaluated using in vitro assays and a zebrafish model. Results: We report 18 new individuals harboring biallelic TARS2 variants. Phenotypically, these individuals show developmental delay/intellectual disability, regression, cerebellar and cerebral atrophy, basal ganglia signal alterations, hypotonia, cerebellar signs, and increased blood lactate. In vitro studies showed that variants within the TARS2301-381 region had decreased binding to Rag GTPases, likely impairing mTORC1 activity. The zebrafish model recapitulated key features of the human phenotype and unraveled dysregulation of downstream targets of mTORC1 signaling. Functional testing of the variants confirmed the pathogenicity in a zebrafish model. Conclusion: We define the clinico-radiological spectrum of TARS2-related mitochondrial disease, unveil the likely involvement of the mTORC1 signaling pathway as a distinct molecular mechanism, and establish a TARS2 zebrafish model as an important tool to study variant pathogenicity.}, author = {Accogli, Andrea and Lin, Sheng-Jia and Severino, Mariasavina and Kim, Sung-Hoon and Huang, Kevin and Rocca, Clarissa and Landsverk, Megan and Zaki, Maha S. and Al-Maawali, Almundher and Srinivasan, Varunvenkat M. and Al-Thihli, Khalid and Schaefer, G. Bradly and Davis, Monica and Tonduti, Davide and Doneda, Chiara and Marten, Lara M. and Mühlhausen, Chris and Gomez, Maria and Lamantea, Eleonora and Mena, Rafael and Nizon, Mathilde and Procaccio, Vincent and Begtrup, Amber and Telegrafi, Aida and Cui, Hong and Schulz, Heidi L. and Mohr, Julia and Biskup, Saskia and Loos, Mariana Amina and Aráoz, Hilda Verónica and Salpietro, Vincenzo and Keppen, Laura Davis and Chitre, Manali and Petree, Cassidy and Raymond, Lucy and Vogt, Julie and Sawyer, Lindsey B. and Basinger, Alice A. and Pedersen, Signe Vandal and Pearson, Toni S. and Grange, Dorothy K. and Lingappa, Lokesh and McDunnah, Paige and Horvath, Rita and Cognè, Benjamin and Isidor, Bertrand and Hahn, Andreas and Gripp, Karen W. and Jafarnejad, Seyed Mehdi and Østergaard, Elsebet and Prada, Carlos E. and Ghezzi, Daniele and Gowda, Vykuntaraju K. and Taylor, Robert W. and Sonenberg, Nahum and Houlden, Henry and Sissler, Marie and Varshney, Gaurav K. and Maroofian, Reza}, issn = {1098-3600}, journal = {Genetics in Medicine}, keywords = {Genetics (clinical)}, number = {11}, publisher = {Elsevier}, title = {{Clinical, neuroradiological, and molecular characterization of mitochondrial threonyl-tRNA-synthetase (TARS2)-related disorder}}, doi = {10.1016/j.gim.2023.100938}, volume = {25}, year = {2023}, } @inproceedings{13120, abstract = {We formalized general (i.e., type-0) grammars using the Lean 3 proof assistant. We defined basic notions of rewrite rules and of words derived by a grammar, and used grammars to show closure of the class of type-0 languages under four operations: union, reversal, concatenation, and the Kleene star. The literature mostly focuses on Turing machine arguments, which are possibly more difficult to formalize. For the Kleene star, we could not follow the literature and came up with our own grammar-based construction.}, author = {Dvorak, Martin and Blanchette, Jasmin}, booktitle = {14th International Conference on Interactive Theorem Proving}, isbn = {9783959772846}, issn = {1868-8969}, location = {Bialystok, Poland}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Closure properties of general grammars - formally verified}}, doi = {10.4230/LIPIcs.ITP.2023.15}, volume = {268}, year = {2023}, } @article{13969, abstract = {Bundling crossings is a strategy which can enhance the readability of graph drawings. In this paper we consider good drawings, i.e., we require that any two edges have at most one common point which can be a common vertex or a crossing. Our main result is that there is a polynomial-time algorithm to compute an 8-approximation of the bundled crossing number of a good drawing with no toothed hole. In general the number of toothed holes has to be added to the 8-approximation. In the special case of circular drawings the approximation factor is 8, this improves upon the 10-approximation of Fink et al. [14]. Our approach also works with the same approximation factor for families of pseudosegments, i.e., curves intersecting at most once. We also show how to compute a 9/2-approximation when the intersection graph of the pseudosegments is bipartite and has no toothed hole.}, author = {Arroyo Guevara, Alan M and Felsner, Stefan}, issn = {1526-1719}, journal = {Journal of Graph Algorithms and Applications}, number = {6}, pages = {433--457}, publisher = {Brown University}, title = {{Approximating the bundled crossing number}}, doi = {10.7155/jgaa.00629}, volume = {27}, year = {2023}, } @inproceedings{14344, abstract = {We study the Hamilton cycle problem with input a random graph G ~ G(n,p) in two different settings. In the first one, G is given to us in the form of randomly ordered adjacency lists while in the second one, we are given the adjacency matrix of G. In each of the two settings we derive a deterministic algorithm that w.h.p. either finds a Hamilton cycle or returns a certificate that such a cycle does not exist for p = p(n) ≥ 0. The running times of our algorithms are O(n) and respectively, each being best possible in its own setting.}, author = {Anastos, Michael}, booktitle = {Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms}, isbn = {9781611977554}, location = {Florence, Italy}, pages = {2286--2323}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Fast algorithms for solving the Hamilton cycle problem with high probability}}, doi = {10.1137/1.9781611977554.ch88}, volume = {2023}, year = {2023}, }