TY - CONF AB - Markov decision processes can be viewed as transformers of probability distributions. While this view is useful from a practical standpoint to reason about trajectories of distributions, basic reachability and safety problems are known to be computationally intractable (i.e., Skolem-hard) to solve in such models. Further, we show that even for simple examples of MDPs, strategies for safety objectives over distributions can require infinite memory and randomization. In light of this, we present a novel overapproximation approach to synthesize strategies in an MDP, such that a safety objective over the distributions is met. More precisely, we develop a new framework for template-based synthesis of certificates as affine distributional and inductive invariants for safety objectives in MDPs. We provide two algorithms within this framework. One can only synthesize memoryless strategies, but has relative completeness guarantees, while the other can synthesize general strategies. The runtime complexity of both algorithms is in PSPACE. We implement these algorithms and show that they can solve several non-trivial examples. AU - Akshay, S. AU - Chatterjee, Krishnendu AU - Meggendorfer, Tobias AU - Zikelic, Dorde ID - 14317 SN - 0302-9743 T2 - International Conference on Computer Aided Verification TI - MDPs as distribution transformers: Affine invariant synthesis for safety objectives VL - 13966 ER - TY - JOUR AB - Clathrin-mediated vesicle trafficking plays central roles in post-Golgi transport. In yeast (Saccharomyces cerevisiae), the AP-1 complex and GGA adaptors are predicted to generate distinct transport vesicles at the trans-Golgi network (TGN), and the epsin-related proteins Ent3p and Ent5p (collectively Ent3p/5p) act as accessories for these adaptors. Recently, we showed that vesicle transport from the TGN is crucial for yeast Rab5 (Vps21p)-mediated endosome formation, and that Ent3p/5p are crucial for this process, whereas AP-1 and GGA adaptors are dispensable. However, these observations were incompatible with previous studies showing that these adaptors are required for Ent3p/5p recruitment to the TGN, and thus the overall mechanism responsible for regulation of Vps21p activity remains ambiguous. Here, we investigated the functional relationships between clathrin adaptors in post-Golgi-mediated Vps21p activation. We show that AP-1 disruption in the ent3Δ5Δ mutant impaired transport of the Vps21p guanine nucleotide exchange factor Vps9p transport to the Vps21p compartment and severely reduced Vps21p activity. Additionally, GGA adaptors, the phosphatidylinositol-4-kinase Pik1p and Rab11 GTPases Ypt31p and Ypt32p were found to have partially overlapping functions for recruitment of AP-1 and Ent3p/5p to the TGN. These findings suggest a distinct role of clathrin adaptors for Vps21p activation in the TGN–endosome trafficking pathway. AU - Nagano, Makoto AU - Aoshima, Kaito AU - Shimamura, Hiroki AU - Siekhaus, Daria E AU - Toshima, Junko Y. AU - Toshima, Jiro ID - 14316 IS - 17 JF - Journal of Cell Science SN - 0021-9533 TI - Distinct role of TGN-resident clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway VL - 136 ER - TY - JOUR AB - 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. AU - Henderson, Paul M AU - Ghazaryan, Areg AU - Zibrov, Alexander A. AU - Young, Andrea F. AU - Serbyn, Maksym ID - 14320 IS - 12 JF - Physical Review B SN - 2469-9950 TI - Deep learning extraction of band structure parameters from density of states: A case study on trilayer graphene VL - 108 ER - TY - THES AB - 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. AU - Brighi, Pietro ID - 12732 SN - 2663-337X TI - Ergodicity breaking in disordered and kinetically constrained quantum many-body systems ER - TY - JOUR AB - 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. AU - Brighi, Pietro AU - Ljubotina, Marko AU - Serbyn, Maksym ID - 14334 IS - 3 JF - SciPost Physics KW - General Physics and Astronomy SN - 2542-4653 TI - Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models VL - 15 ER - TY - JOUR AB - 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. AU - Al Hyder, Ragheed AU - Cappellaro, Alberto AU - Lemeshko, Mikhail AU - Volosniev, Artem ID - 14321 IS - 10 JF - The Journal of Chemical Physics KW - Physical and Theoretical Chemistry KW - General Physics and Astronomy SN - 0021-9606 TI - Achiral dipoles on a ferromagnet can affect its magnetization direction VL - 159 ER - TY - JOUR AB - 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. AU - Lorenc, Dusan AU - Alpichshev, Zhanybek ID - 14342 IS - 9 JF - Applied Physics Letters SN - 0003-6951 TI - Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam VL - 123 ER - TY - JOUR AB - 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. AU - Scarselli, Davide AU - Lopez Alonso, Jose M AU - Varshney, Atul AU - Hof, Björn ID - 14341 IS - 7977 JF - Nature SN - 0028-0836 TI - Turbulence suppression by cardiac-cycle-inspired driving of pipe flow VL - 621 ER - TY - JOUR AB - 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. AU - Accogli, Andrea AU - Lin, Sheng-Jia AU - Severino, Mariasavina AU - Kim, Sung-Hoon AU - Huang, Kevin AU - Rocca, Clarissa AU - Landsverk, Megan AU - Zaki, Maha S. AU - Al-Maawali, Almundher AU - Srinivasan, Varunvenkat M. AU - Al-Thihli, Khalid AU - Schaefer, G. Bradly AU - Davis, Monica AU - Tonduti, Davide AU - Doneda, Chiara AU - Marten, Lara M. AU - Mühlhausen, Chris AU - Gomez, Maria AU - Lamantea, Eleonora AU - Mena, Rafael AU - Nizon, Mathilde AU - Procaccio, Vincent AU - Begtrup, Amber AU - Telegrafi, Aida AU - Cui, Hong AU - Schulz, Heidi L. AU - Mohr, Julia AU - Biskup, Saskia AU - Loos, Mariana Amina AU - Aráoz, Hilda Verónica AU - Salpietro, Vincenzo AU - Keppen, Laura Davis AU - Chitre, Manali AU - Petree, Cassidy AU - Raymond, Lucy AU - Vogt, Julie AU - Sawyer, Lindsey B. AU - Basinger, Alice A. AU - Pedersen, Signe Vandal AU - Pearson, Toni S. AU - Grange, Dorothy K. AU - Lingappa, Lokesh AU - McDunnah, Paige AU - Horvath, Rita AU - Cognè, Benjamin AU - Isidor, Bertrand AU - Hahn, Andreas AU - Gripp, Karen W. AU - Jafarnejad, Seyed Mehdi AU - Østergaard, Elsebet AU - Prada, Carlos E. AU - Ghezzi, Daniele AU - Gowda, Vykuntaraju K. AU - Taylor, Robert W. AU - Sonenberg, Nahum AU - Houlden, Henry AU - Sissler, Marie AU - Varshney, Gaurav K. AU - Maroofian, Reza ID - 14368 IS - 11 JF - Genetics in Medicine KW - Genetics (clinical) SN - 1098-3600 TI - Clinical, neuroradiological, and molecular characterization of mitochondrial threonyl-tRNA-synthetase (TARS2)-related disorder VL - 25 ER - TY - CONF AB - 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. AU - Dvorak, Martin AU - Blanchette, Jasmin ID - 13120 SN - 9783959772846 T2 - 14th International Conference on Interactive Theorem Proving TI - Closure properties of general grammars - formally verified VL - 268 ER -