TY - JOUR AB - We propose a method to enhance the visual detail of a water surface simulation. Our method works as a post-processing step which takes a simulation as input and increases its apparent resolution by simulating many detailed Lagrangian water waves on top of it. We extend linear water wave theory to work in non-planar domains which deform over time, and we discretize the theory using Lagrangian wave packets attached to spline curves. The method is numerically stable and trivially parallelizable, and it produces high frequency ripples with dispersive wave-like behaviors customized to the underlying fluid simulation. AU - Skrivan, Tomas AU - Soderstrom, Andreas AU - Johansson, John AU - Sprenger, Christoph AU - Museth, Ken AU - Wojtan, Christopher J ID - 8535 IS - 4 JF - ACM Transactions on Graphics SN - 07300301 TI - Wave curves: Simulating Lagrangian water waves on dynamically deforming surfaces VL - 39 ER - TY - JOUR AB - Cohomological and K-theoretic stable bases originated from the study of quantum cohomology and quantum K-theory. Restriction formula for cohomological stable bases played an important role in computing the quantum connection of cotangent bundle of partial flag varieties. In this paper we study the K-theoretic stable bases of cotangent bundles of flag varieties. We describe these bases in terms of the action of the affine Hecke algebra and the twisted group algebra of KostantKumar. Using this algebraic description and the method of root polynomials, we give a restriction formula of the stable bases. We apply it to obtain the restriction formula for partial flag varieties. We also build a relation between the stable basis and the Casselman basis in the principal series representations of the Langlands dual group. As an application, we give a closed formula for the transition matrix between Casselman basis and the characteristic functions. AU - Su, C. AU - Zhao, Gufang AU - Zhong, C. ID - 8539 IS - 3 JF - Annales Scientifiques de l'Ecole Normale Superieure SN - 0012-9593 TI - On the K-theory stable bases of the springer resolution VL - 53 ER - TY - GEN AB - This datasets comprises all data shown in plots of the submitted article "Converting microwave and telecom photons with a silicon photonic nanomechanical interface". Additional raw data are available from the corresponding author on reasonable request. AU - Arnold, Georg M AU - Wulf, Matthias AU - Barzanjeh, Shabir AU - Redchenko, Elena AU - Rueda Sanchez, Alfredo R AU - Hease, William J AU - Hassani, Farid AU - Fink, Johannes M ID - 13056 TI - Converting microwave and telecom photons with a silicon photonic nanomechanical interface ER - TY - JOUR AB - Copper (Cu) is an essential trace element for all living organisms and used as cofactor in key enzymes of important biological processes, such as aerobic respiration or superoxide dismutation. However, due to its toxicity, cells have developed elaborate mechanisms for Cu homeostasis, which balance Cu supply for cuproprotein biogenesis with the need to remove excess Cu. This review summarizes our current knowledge on bacterial Cu homeostasis with a focus on Gram-negative bacteria and describes the multiple strategies that bacteria use for uptake, storage and export of Cu. We furthermore describe general mechanistic principles that aid the bacterial response to toxic Cu concentrations and illustrate dedicated Cu relay systems that facilitate Cu delivery for cuproenzyme biogenesis. Progress in understanding how bacteria avoid Cu poisoning while maintaining a certain Cu quota for cell proliferation is of particular importance for microbial pathogens because Cu is utilized by the host immune system for attenuating pathogen survival in host cells. AU - Andrei, Andreea AU - Öztürk, Yavuz AU - Khalfaoui-Hassani, Bahia AU - Rauch, Juna AU - Marckmann, Dorian AU - Trasnea, Petru Iulian AU - Daldal, Fevzi AU - Koch, Hans-Georg ID - 8579 IS - 9 JF - Membranes TI - Cu homeostasis in bacteria: The ins and outs VL - 10 ER - TY - JOUR AB - Glioblastoma is the most malignant cancer in the brain and currently incurable. It is urgent to identify effective targets for this lethal disease. Inhibition of such targets should suppress the growth of cancer cells and, ideally also precancerous cells for early prevention, but minimally affect their normal counterparts. Using genetic mouse models with neural stem cells (NSCs) or oligodendrocyte precursor cells (OPCs) as the cells‐of‐origin/mutation, it is shown that the susceptibility of cells within the development hierarchy of glioma to the knockout of insulin‐like growth factor I receptor (IGF1R) is determined not only by their oncogenic states, but also by their cell identities/states. Knockout of IGF1R selectively disrupts the growth of mutant and transformed, but not normal OPCs, or NSCs. The desirable outcome of IGF1R knockout on cell growth requires the mutant cells to commit to the OPC identity regardless of its development hierarchical status. At the molecular level, oncogenic mutations reprogram the cellular network of OPCs and force them to depend more on IGF1R for their growth. A new‐generation brain‐penetrable, orally available IGF1R inhibitor harnessing tumor OPCs in the brain is also developed. The findings reveal the cellular window of IGF1R targeting and establish IGF1R as an effective target for the prevention and treatment of glioblastoma. AU - Tian, Anhao AU - Kang, Bo AU - Li, Baizhou AU - Qiu, Biying AU - Jiang, Wenhong AU - Shao, Fangjie AU - Gao, Qingqing AU - Liu, Rui AU - Cai, Chengwei AU - Jing, Rui AU - Wang, Wei AU - Chen, Pengxiang AU - Liang, Qinghui AU - Bao, Lili AU - Man, Jianghong AU - Wang, Yan AU - Shi, Yu AU - Li, Jin AU - Yang, Minmin AU - Wang, Lisha AU - Zhang, Jianmin AU - Hippenmeyer, Simon AU - Zhu, Junming AU - Bian, Xiuwu AU - Wang, Ying‐Jie AU - Liu, Chong ID - 8592 IS - 21 JF - Advanced Science KW - General Engineering KW - General Physics and Astronomy KW - General Materials Science KW - Medicine (miscellaneous) KW - General Chemical Engineering KW - Biochemistry KW - Genetics and Molecular Biology (miscellaneous) SN - 2198-3844 TI - Oncogenic state and cell identity combinatorially dictate the susceptibility of cells within glioma development hierarchy to IGF1R targeting VL - 7 ER - TY - JOUR AB - Aqueous iodine based electrochemical energy storage is considered a potential candidate to improve sustainability and performance of current battery and supercapacitor technology. It harnesses the redox activity of iodide, iodine, and polyiodide species in the confined geometry of nanoporous carbon electrodes. However, current descriptions of the electrochemical reaction mechanism to interconvert these species are elusive. Here we show that electrochemical oxidation of iodide in nanoporous carbons forms persistent solid iodine deposits. Confinement slows down dissolution into triiodide and pentaiodide, responsible for otherwise significant self-discharge via shuttling. The main tools for these insights are in situ Raman spectroscopy and in situ small and wide-angle X-ray scattering (in situ SAXS/WAXS). In situ Raman confirms the reversible formation of triiodide and pentaiodide. In situ SAXS/WAXS indicates remarkable amounts of solid iodine deposited in the carbon nanopores. Combined with stochastic modeling, in situ SAXS allows quantifying the solid iodine volume fraction and visualizing the iodine structure on 3D lattice models at the sub-nanometer scale. Based on the derived mechanism, we demonstrate strategies for improved iodine pore filling capacity and prevention of self-discharge, applicable to hybrid supercapacitors and batteries. AU - Prehal, Christian AU - Fitzek, Harald AU - Kothleitner, Gerald AU - Presser, Volker AU - Gollas, Bernhard AU - Freunberger, Stefan Alexander AU - Abbas, Qamar ID - 8568 JF - Nature Communications KW - General Biochemistry KW - Genetics and Molecular Biology KW - General Physics and Astronomy KW - General Chemistry SN - 2041-1723 TI - Persistent and reversible solid iodine electrodeposition in nanoporous carbons VL - 11 ER - TY - JOUR AB - The parabigeminal nucleus (PBG) is the mammalian homologue to the isthmic complex of other vertebrates. Optogenetic stimulation of the PBG induces freezing and escape in mice, a result thought to be caused by a PBG projection to the central nucleus of the amygdala. However, the isthmic complex, including the PBG, has been classically considered satellite nuclei of the Superior Colliculus (SC), which upon stimulation of its medial part also triggers fear and avoidance reactions. As the PBG-SC connectivity is not well characterized, we investigated whether the topology of the PBG projection to the SC could be related to the behavioral consequences of PBG stimulation. To that end, we performed immunohistochemistry, in situ hybridization and neural tracer injections in the SC and PBG in a diurnal rodent, the Octodon degus. We found that all PBG neurons expressed both glutamatergic and cholinergic markers and were distributed in clearly defined anterior (aPBG) and posterior (pPBG) subdivisions. The pPBG is connected reciprocally and topographically to the ipsilateral SC, whereas the aPBG receives afferent axons from the ipsilateral SC and projected exclusively to the contralateral SC. This contralateral projection forms a dense field of terminals that is restricted to the medial SC, in correspondence with the SC representation of the aerial binocular field which, we also found, in O. degus prompted escape reactions upon looming stimulation. Therefore, this specialized topography allows binocular interactions in the SC region controlling responses to aerial predators, suggesting a link between the mechanisms by which the SC and PBG produce defensive behaviors. AU - Deichler, Alfonso AU - Carrasco, Denisse AU - Lopez-Jury, Luciana AU - Vega Zuniga, Tomas A AU - Marquez, Natalia AU - Mpodozis, Jorge AU - Marin, Gonzalo ID - 8643 JF - Scientific Reports TI - A specialized reciprocal connectivity suggests a link between the mechanisms by which the superior colliculus and parabigeminal nucleus produce defensive behaviors in rodents VL - 10 ER - TY - JOUR AB - Epistasis, the context-dependence of the contribution of an amino acid substitution to fitness, is common in evolution. To detect epistasis, fitness must be measured for at least four genotypes: the reference genotype, two different single mutants and a double mutant with both of the single mutations. For higher-order epistasis of the order n, fitness has to be measured for all 2n genotypes of an n-dimensional hypercube in genotype space forming a ‘combinatorially complete dataset’. So far, only a handful of such datasets have been produced by manual curation. Concurrently, random mutagenesis experiments have produced measurements of fitness and other phenotypes in a high-throughput manner, potentially containing a number of combinatorially complete datasets. We present an effective recursive algorithm for finding all hypercube structures in random mutagenesis experimental data. To test the algorithm, we applied it to the data from a recent HIS3 protein dataset and found all 199 847 053 unique combinatorially complete genotype combinations of dimensionality ranging from 2 to 12. The algorithm may be useful for researchers looking for higher-order epistasis in their high-throughput experimental data. AU - Esteban, Laura A AU - Lonishin, Lyubov R AU - Bobrovskiy, Daniil M AU - Leleytner, Gregory AU - Bogatyreva, Natalya S AU - Kondrashov, Fyodor AU - Ivankov, Dmitry N ID - 8645 IS - 6 JF - Bioinformatics SN - 1367-4803 TI - HypercubeME: Two hundred million combinatorially complete datasets from a single experiment VL - 36 ER - TY - JOUR AB - Error analysis and data visualization of positive COVID-19 cases in 27 countries have been performed up to August 8, 2020. This survey generally observes a progression from early exponential growth transitioning to an intermediate power-law growth phase, as recently suggested by Ziff and Ziff. The occurrence of logistic growth after the power-law phase with lockdowns or social distancing may be described as an effect of avoidance. A visualization of the power-law growth exponent over short time windows is qualitatively similar to the Bhatia visualization for pandemic progression. Visualizations like these can indicate the onset of second waves and may influence social policy. AU - Merrin, Jack ID - 8597 IS - 6 JF - Physical Biology TI - Differences in power law growth over time and indicators of COVID-19 pandemic progression worldwide VL - 17 ER - TY - JOUR AB - Extrasynaptic actions of glutamate are limited by high-affinity transporters expressed by perisynaptic astroglial processes (PAPs): this helps maintain point-to-point transmission in excitatory circuits. Memory formation in the brain is associated with synaptic remodeling, but how this affects PAPs and therefore extrasynaptic glutamate actions is poorly understood. Here, we used advanced imaging methods, in situ and in vivo, to find that a classical synaptic memory mechanism, long-term potentiation (LTP), triggers withdrawal of PAPs from potentiated synapses. Optical glutamate sensors combined with patch-clamp and 3D molecular localization reveal that LTP induction thus prompts spatial retreat of astroglial glutamate transporters, boosting glutamate spillover and NMDA-receptor-mediated inter-synaptic cross-talk. The LTP-triggered PAP withdrawal involves NKCC1 transporters and the actin-controlling protein cofilin but does not depend on major Ca2+-dependent cascades in astrocytes. We have therefore uncovered a mechanism by which a memory trace at one synapse could alter signal handling by multiple neighboring connections. AU - Henneberger, Christian AU - Bard, Lucie AU - Panatier, Aude AU - Reynolds, James P. AU - Kopach, Olga AU - Medvedev, Nikolay I. AU - Minge, Daniel AU - Herde, Michel K. AU - Anders, Stefanie AU - Kraev, Igor AU - Heller, Janosch P. AU - Rama, Sylvain AU - Zheng, Kaiyu AU - Jensen, Thomas P. AU - Sanchez-Romero, Inmaculada AU - Jackson, Colin J. AU - Janovjak, Harald L AU - Ottersen, Ole Petter AU - Nagelhus, Erlend Arnulf AU - Oliet, Stephane H.R. AU - Stewart, Michael G. AU - Nägerl, U. VAlentin AU - Rusakov, Dmitri A. ID - 8674 IS - 5 JF - Neuron SN - 08966273 TI - LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia VL - 108 ER - TY - JOUR AB - Nature creates electrons with two values of the spin projection quantum number. In certain applications, it is important to filter electrons with one spin projection from the rest. Such filtering is not trivial, since spin-dependent interactions are often weak, and cannot lead to any substantial effect. Here we propose an efficient spin filter based upon scattering from a two-dimensional crystal, which is made of aligned point magnets. The polarization of the outgoing electron flux is controlled by the crystal, and reaches maximum at specific values of the parameters. In our scheme, polarization increase is accompanied by higher reflectivity of the crystal. High transmission is feasible in scattering from a quantum cavity made of two crystals. Our findings can be used for studies of low-energy spin-dependent scattering from two-dimensional ordered structures made of magnetic atoms or aligned chiral molecules. AU - Ghazaryan, Areg AU - Lemeshko, Mikhail AU - Volosniev, Artem ID - 8652 JF - Communications Physics SN - 2399-3650 TI - Filtering spins by scattering from a lattice of point magnets VL - 3 ER - TY - JOUR AB - Pancreatic islets play an essential role in regulating blood glucose level. Although the molecular pathways underlying islet cell differentiation are beginning to be resolved, the cellular basis of islet morphogenesis and fate allocation remain unclear. By combining unbiased and targeted lineage tracing, we address the events leading to islet formation in the mouse. From the statistical analysis of clones induced at multiple embryonic timepoints, here we show that, during the secondary transition, islet formation involves the aggregation of multiple equipotent endocrine progenitors that transition from a phase of stochastic amplification by cell division into a phase of sublineage restriction and limited islet fission. Together, these results explain quantitatively the heterogeneous size distribution and degree of polyclonality of maturing islets, as well as dispersion of progenitors within and between islets. Further, our results show that, during the secondary transition, α- and β-cells are generated in a contemporary manner. Together, these findings provide insight into the cellular basis of islet development. AU - Sznurkowska, Magdalena K. AU - Hannezo, Edouard B AU - Azzarelli, Roberta AU - Chatzeli, Lemonia AU - Ikeda, Tatsuro AU - Yoshida, Shosei AU - Philpott, Anna AU - Simons, Benjamin D ID - 8669 JF - Nature Communications TI - Tracing the cellular basis of islet specification in mouse pancreas VL - 11 ER - TY - JOUR AB - Cell fate transitions are key to development and homeostasis. It is thus essential to understand the cellular mechanisms controlling fate transitions. Cell division has been implicated in fate decisions in many stem cell types, including neuronal and epithelial progenitors. In other stem cells, such as embryonic stem (ES) cells, the role of division remains unclear. Here, we show that exit from naive pluripotency in mouse ES cells generally occurs after a division. We further show that exit timing is strongly correlated between sister cells, which remain connected by cytoplasmic bridges long after division, and that bridge abscission progressively accelerates as cells exit naive pluripotency. Finally, interfering with abscission impairs naive pluripotency exit, and artificially inducing abscission accelerates it. Altogether, our data indicate that a switch in the division machinery leading to faster abscission regulates pluripotency exit. Our study identifies abscission as a key cellular process coupling cell division to fate transitions. AU - Chaigne, Agathe AU - Labouesse, Céline AU - White, Ian J. AU - Agnew, Meghan AU - Hannezo, Edouard B AU - Chalut, Kevin J. AU - Paluch, Ewa K. ID - 8672 IS - 2 JF - Developmental Cell SN - 15345807 TI - Abscission couples cell division to embryonic stem cell fate VL - 55 ER - TY - JOUR AB - In the computation of the material properties of random alloys, the method of 'special quasirandom structures' attempts to approximate the properties of the alloy on a finite volume with higher accuracy by replicating certain statistics of the random atomic lattice in the finite volume as accurately as possible. In the present work, we provide a rigorous justification for a variant of this method in the framework of the Thomas–Fermi–von Weizsäcker (TFW) model. Our approach is based on a recent analysis of a related variance reduction method in stochastic homogenization of linear elliptic PDEs and the locality properties of the TFW model. Concerning the latter, we extend an exponential locality result by Nazar and Ortner to include point charges, a result that may be of independent interest. AU - Fischer, Julian L AU - Kniely, Michael ID - 8697 IS - 11 JF - Nonlinearity SN - 09517715 TI - Variance reduction for effective energies of random lattices in the Thomas-Fermi-von Weizsäcker model VL - 33 ER - TY - JOUR AB - Animal development entails the organization of specific cell types in space and time, and spatial patterns must form in a robust manner. In the zebrafish spinal cord, neural progenitors form stereotypic patterns despite noisy morphogen signaling and large-scale cellular rearrangements during morphogenesis and growth. By directly measuring adhesion forces and preferences for three types of endogenous neural progenitors, we provide evidence for the differential adhesion model in which differences in intercellular adhesion mediate cell sorting. Cell type–specific combinatorial expression of different classes of cadherins (N-cadherin, cadherin 11, and protocadherin 19) results in homotypic preference ex vivo and patterning robustness in vivo. Furthermore, the differential adhesion code is regulated by the sonic hedgehog morphogen gradient. We propose that robust patterning during tissue morphogenesis results from interplay between adhesion-based self-organization and morphogen-directed patterning. AU - Tsai, Tony Y.-C. AU - Sikora, Mateusz K AU - Xia, Peng AU - Colak-Champollion, Tugba AU - Knaut, Holger AU - Heisenberg, Carl-Philipp J AU - Megason, Sean G. ID - 8680 IS - 6512 JF - Science KW - Multidisciplinary SN - 0036-8075 TI - An adhesion code ensures robust pattern formation during tissue morphogenesis VL - 370 ER - TY - JOUR AB - The α–z Rényi relative entropies are a two-parameter family of Rényi relative entropies that are quantum generalizations of the classical α-Rényi relative entropies. In the work [Adv. Math. 365, 107053 (2020)], we decided the full range of (α, z) for which the data processing inequality (DPI) is valid. In this paper, we give algebraic conditions for the equality in DPI. For the full range of parameters (α, z), we give necessary conditions and sufficient conditions. For most parameters, we give equivalent conditions. This generalizes and strengthens the results of Leditzky et al. [Lett. Math. Phys. 107, 61–80 (2017)]. AU - Zhang, Haonan ID - 8670 IS - 10 JF - Journal of Mathematical Physics SN - 00222488 TI - Equality conditions of data processing inequality for α-z Rényi relative entropies VL - 61 ER - TY - JOUR AB - The brain represents and reasons probabilistically about complex stimuli and motor actions using a noisy, spike-based neural code. A key building block for such neural computations, as well as the basis for supervised and unsupervised learning, is the ability to estimate the surprise or likelihood of incoming high-dimensional neural activity patterns. Despite progress in statistical modeling of neural responses and deep learning, current approaches either do not scale to large neural populations or cannot be implemented using biologically realistic mechanisms. Inspired by the sparse and random connectivity of real neuronal circuits, we present a model for neural codes that accurately estimates the likelihood of individual spiking patterns and has a straightforward, scalable, efficient, learnable, and realistic neural implementation. This model’s performance on simultaneously recorded spiking activity of >100 neurons in the monkey visual and prefrontal cortices is comparable with or better than that of state-of-the-art models. Importantly, the model can be learned using a small number of samples and using a local learning rule that utilizes noise intrinsic to neural circuits. Slower, structural changes in random connectivity, consistent with rewiring and pruning processes, further improve the efficiency and sparseness of the resulting neural representations. Our results merge insights from neuroanatomy, machine learning, and theoretical neuroscience to suggest random sparse connectivity as a key design principle for neuronal computation. AU - Maoz, Ori AU - Tkačik, Gašper AU - Esteki, Mohamad Saleh AU - Kiani, Roozbeh AU - Schneidman, Elad ID - 8698 IS - 40 JF - Proceedings of the National Academy of Sciences of the United States of America SN - 00278424 TI - Learning probabilistic neural representations with randomly connected circuits VL - 117 ER - TY - CONF AB - Traditional robotic control suits require profound task-specific knowledge for designing, building and testing control software. The rise of Deep Learning has enabled end-to-end solutions to be learned entirely from data, requiring minimal knowledge about the application area. We design a learning scheme to train end-to-end linear dynamical systems (LDS)s by gradient descent in imitation learning robotic domains. We introduce a new regularization loss component together with a learning algorithm that improves the stability of the learned autonomous system, by forcing the eigenvalues of the internal state updates of an LDS to be negative reals. We evaluate our approach on a series of real-life and simulated robotic experiments, in comparison to linear and nonlinear Recurrent Neural Network (RNN) architectures. Our results show that our stabilizing method significantly improves test performance of LDS, enabling such linear models to match the performance of contemporary nonlinear RNN architectures. A video of the obstacle avoidance performance of our method on a mobile robot, in unseen environments, compared to other methods can be viewed at https://youtu.be/mhEsCoNao5E. AU - Lechner, Mathias AU - Hasani, Ramin AU - Rus, Daniela AU - Grosu, Radu ID - 8704 SN - 10504729 T2 - Proceedings - IEEE International Conference on Robotics and Automation TI - Gershgorin loss stabilizes the recurrent neural network compartment of an end-to-end robot learning scheme ER - TY - GEN AB - A binary neutron star merger has been observed in a multi-messenger detection of gravitational wave (GW) and electromagnetic (EM) radiation. Binary neutron stars that merge within a Hubble time, as well as many other compact binaries, are expected to form via common envelope evolution. Yet five decades of research on common envelope evolution have not yet resulted in a satisfactory understanding of the multi-spatial multi-timescale evolution for the systems that lead to compact binaries. In this paper, we report on the first successful simulations of common envelope ejection leading to binary neutron star formation in 3D hydrodynamics. We simulate the dynamical inspiral phase of the interaction between a 12M⊙ red supergiant and a 1.4M⊙ neutron star for different initial separations and initial conditions. For all of our simulations, we find complete envelope ejection and final orbital separations of af≈1.3-5.1R⊙ depending on the simulation and criterion, leading to binary neutron stars that can merge within a Hubble time. We find αCE-equivalent efficiencies of ≈0.1-2.7 depending on the simulation and criterion, but this may be specific for these extended progenitors. We fully resolve the core of the star to ≲0.005R⊙ and our 3D hydrodynamics simulations are informed by an adjusted 1D analytic energy formalism and a 2D kinematics study in order to overcome the prohibitive computational cost of simulating these systems. The framework we develop in this paper can be used to simulate a wide variety of interactions between stars, from stellar mergers to common envelope episodes leading to GW sources. AU - Jamie A. P. Law-Smith, Jamie A. P. Law-Smith AU - Everson, Rosa Wallace AU - Enrico Ramirez-Ruiz, Enrico Ramirez-Ruiz AU - Mink, Selma E. de AU - Son, Lieke A. C. van AU - Götberg, Ylva Louise Linsdotter AU - Zellmann, Stefan AU - Alejandro Vigna-Gómez, Alejandro Vigna-Gómez AU - Renzo, Mathieu AU - Wu, Samantha AU - Schrøder, Sophie L. AU - Foley, Ryan J. AU - Tenley Hutchinson-Smith, Tenley Hutchinson-Smith ID - 14096 T2 - arXiv TI - Successful common envelope ejection and binary neutron star formation in 3D hydrodynamics ER - TY - JOUR AB - In the high spin–orbit-coupled Sr2IrO4, the high sensitivity of the ground state to the details of the local lattice structure shows a large potential for the manipulation of the functional properties by inducing local lattice distortions. We use epitaxial strain to modify the Ir–O bond geometry in Sr2IrO4 and perform momentum-dependent resonant inelastic X-ray scattering (RIXS) at the metal and at the ligand sites to unveil the response of the low-energy elementary excitations. We observe that the pseudospin-wave dispersion for tensile-strained Sr2IrO4 films displays large softening along the [h,0] direction, while along the [h,h] direction it shows hardening. This evolution reveals a renormalization of the magnetic interactions caused by a strain-driven cross-over from anisotropic to isotropic interactions between the magnetic moments. Moreover, we detect dispersive electron–hole pair excitations which shift to lower (higher) energies upon compressive (tensile) strain, manifesting a reduction (increase) in the size of the charge gap. This behavior shows an intimate coupling between charge excitations and lattice distortions in Sr2IrO4, originating from the modified hopping elements between the t2g orbitals. Our work highlights the central role played by the lattice degrees of freedom in determining both the pseudospin and charge excitations of Sr2IrO4 and provides valuable information toward the control of the ground state of complex oxides in the presence of high spin–orbit coupling. AU - Paris, Eugenio AU - Tseng, Yi AU - Paerschke, Ekaterina AU - Zhang, Wenliang AU - Upton, Mary H AU - Efimenko, Anna AU - Rolfs, Katharina AU - McNally, Daniel E AU - Maurel, Laura AU - Naamneh, Muntaser AU - Caputo, Marco AU - Strocov, Vladimir N AU - Wang, Zhiming AU - Casa, Diego AU - Schneider, Christof W AU - Pomjakushina, Ekaterina AU - Wohlfeld, Krzysztof AU - Radovic, Milan AU - Schmitt, Thorsten ID - 8699 IS - 40 JF - Proceedings of the National Academy of Sciences of the United States of America SN - 00278424 TI - Strain engineering of the charge and spin-orbital interactions in Sr2IrO4 VL - 117 ER -