@inbook{649, abstract = {We give a short overview on a recently developed notion of Ricci curvature for discrete spaces. This notion relies on geodesic convexity properties of the relative entropy along geodesics in the space of probability densities, for a metric which is similar to (but different from) the 2-Wasserstein metric. The theory can be considered as a discrete counterpart to the theory of Ricci curvature for geodesic measure spaces developed by Lott–Sturm–Villani.}, author = {Maas, Jan}, booktitle = {Modern Approaches to Discrete Curvature}, editor = {Najman, Laurent and Romon, Pascal}, isbn = {9783319580012}, issn = {9783319580029}, pages = {159 -- 174}, publisher = {Springer}, title = {{Entropic Ricci curvature for discrete spaces}}, doi = {10.1007/978-3-319-58002-9_5}, volume = {2184}, year = {2017}, } @inproceedings{1194, abstract = {Termination is one of the basic liveness properties, and we study the termination problem for probabilistic programs with real-valued variables. Previous works focused on the qualitative problem that asks whether an input program terminates with probability~1 (almost-sure termination). A powerful approach for this qualitative problem is the notion of ranking supermartingales with respect to a given set of invariants. The quantitative problem (probabilistic termination) asks for bounds on the termination probability. A fundamental and conceptual drawback of the existing approaches to address probabilistic termination is that even though the supermartingales consider the probabilistic behavior of the programs, the invariants are obtained completely ignoring the probabilistic aspect. In this work we address the probabilistic termination problem for linear-arithmetic probabilistic programs with nondeterminism. We define the notion of {\em stochastic invariants}, which are constraints along with a probability bound that the constraints hold. We introduce a concept of {\em repulsing supermartingales}. First, we show that repulsing supermartingales can be used to obtain bounds on the probability of the stochastic invariants. Second, we show the effectiveness of repulsing supermartingales in the following three ways: (1)~With a combination of ranking and repulsing supermartingales we can compute lower bounds on the probability of termination; (2)~repulsing supermartingales provide witnesses for refutation of almost-sure termination; and (3)~with a combination of ranking and repulsing supermartingales we can establish persistence properties of probabilistic programs. We also present results on related computational problems and an experimental evaluation of our approach on academic examples. }, author = {Chatterjee, Krishnendu and Novotny, Petr and Zikelic, Djordje}, issn = {0730-8566}, location = {Paris, France}, number = {1}, pages = {145 -- 160}, publisher = {ACM}, title = {{Stochastic invariants for probabilistic termination}}, doi = {10.1145/3009837.3009873}, volume = {52}, year = {2017}, } @article{704, abstract = {How the organization of genes on a chromosome shapes adaptation is essential for understanding evolutionary paths. Here, we investigate how adaptation to rapidly increasing levels of antibiotic depends on the chromosomal neighborhood of a drug-resistance gene inserted at different positions of the Escherichia coli chromosome. Using a dual-fluorescence reporter that allows us to distinguish gene amplifications from other up-mutations, we track in real-time adaptive changes in expression of the drug-resistance gene. We find that the relative contribution of several mutation types differs systematically between loci due to properties of neighboring genes: essentiality, expression, orientation, termination, and presence of duplicates. These properties determine rate and fitness effects of gene amplification, deletions, and mutations compromising transcriptional termination. Thus, the adaptive potential of a gene under selection is a system-property with a complex genetic basis that is specific for each chromosomal locus, and it can be inferred from detailed functional and genomic data.}, author = {Steinrück, Magdalena and Guet, Calin C}, issn = {2050-084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Complex chromosomal neighborhood effects determine the adaptive potential of a gene under selection}}, doi = {10.7554/eLife.25100}, volume = {6}, year = {2017}, } @article{1028, abstract = {Optogenetics and photopharmacology provide spatiotemporally precise control over protein interactions and protein function in cells and animals. Optogenetic methods that are sensitive to green light and can be used to break protein complexes are not broadly available but would enable multichromatic experiments with previously inaccessible biological targets. Herein, we repurposed cobalamin (vitamin B12) binding domains of bacterial CarH transcription factors for green-light-induced receptor dissociation. In cultured cells, we observed oligomerization-induced cell signaling for the fibroblast growth factor receptor 1 fused to cobalamin-binding domains in the dark that was rapidly eliminated upon illumination. In zebrafish embryos expressing fusion receptors, green light endowed control over aberrant fibroblast growth factor signaling during development. Green-light-induced domain dissociation and light-inactivated receptors will critically expand the optogenetic toolbox for control of biological processes.}, author = {Kainrath, Stephanie and Stadler, Manuela and Gschaider-Reichhart, Eva and Distel, Martin and Janovjak, Harald L}, issn = {1433-7851}, journal = {Angewandte Chemie - International Edition}, number = {16}, pages = {4608--4611}, publisher = {Wiley-Blackwell}, title = {{Green-light-induced inactivation of receptor signaling using cobalamin-binding domains}}, doi = {10.1002/anie.201611998}, volume = {56}, year = {2017}, } @article{735, abstract = {Cell-cell contact formation constitutes an essential step in evolution, leading to the differentiation of specialized cell types. However, remarkably little is known about whether and how the interplay between contact formation and fate specification affects development. Here, we identify a positive feedback loop between cell-cell contact duration, morphogen signaling, and mesendoderm cell-fate specification during zebrafish gastrulation. We show that long-lasting cell-cell contacts enhance the competence of prechordal plate (ppl) progenitor cells to respond to Nodal signaling, required for ppl cell-fate specification. We further show that Nodal signaling promotes ppl cell-cell contact duration, generating a positive feedback loop between ppl cell-cell contact duration and cell-fate specification. Finally, by combining mathematical modeling and experimentation, we show that this feedback determines whether anterior axial mesendoderm cells become ppl or, instead, turn into endoderm. Thus, the interdependent activities of cell-cell signaling and contact formation control fate diversification within the developing embryo.}, author = {Barone, Vanessa and Lang, Moritz and Krens, Gabriel and Pradhan, Saurabh and Shamipour, Shayan and Sako, Keisuke and Sikora, Mateusz K and Guet, Calin C and Heisenberg, Carl-Philipp J}, issn = {1534-5807}, journal = {Developmental Cell}, number = {2}, pages = {198 -- 211}, publisher = {Cell Press}, title = {{An effective feedback loop between cell-cell contact duration and morphogen signaling determines cell fate}}, doi = {10.1016/j.devcel.2017.09.014}, volume = {43}, year = {2017}, } @article{682, abstract = {Left-right asymmetry is a fundamental feature of higher-order brain structure; however, the molecular basis of brain asymmetry remains unclear. We recently identified structural and functional asymmetries in mouse hippocampal circuitry that result from the asymmetrical distribution of two distinct populations of pyramidal cell synapses that differ in the density of the NMDA receptor subunit GluRε2 (also known as NR2B, GRIN2B or GluN2B). By examining the synaptic distribution of ε2 subunits, we previously found that β2-microglobulin-deficient mice, which lack cell surface expression of the vast majority of major histocompatibility complex class I (MHCI) proteins, do not exhibit circuit asymmetry. In the present study, we conducted electrophysiological and anatomical analyses on the hippocampal circuitry of mice with a knockout of the paired immunoglobulin-like receptor B (PirB), an MHCI receptor. As in β2-microglobulin-deficient mice, the PirB-deficient hippocampus lacked circuit asymmetries. This finding that MHCI loss-of-function mice and PirB knockout mice have identical phenotypes suggests that MHCI signals that produce hippocampal asymmetries are transduced through PirB. Our results provide evidence for a critical role of the MHCI/PirB signaling system in the generation of asymmetries in hippocampal circuitry.}, author = {Ukai, Hikari and Kawahara, Aiko and Hirayama, Keiko and Case, Matthew J and Aino, Shotaro and Miyabe, Masahiro and Wakita, Ken and Oogi, Ryohei and Kasayuki, Michiyo and Kawashima, Shihomi and Sugimoto, Shunichi and Chikamatsu, Kanako and Nitta, Noritaka and Koga, Tsuneyuki and Shigemoto, Ryuichi and Takai, Toshiyuki and Ito, Isao}, issn = {1932-6203}, journal = {PLoS One}, number = {6}, publisher = {Public Library of Science}, title = {{PirB regulates asymmetries in hippocampal circuitry}}, doi = {10.1371/journal.pone.0179377}, volume = {12}, year = {2017}, } @article{1029, abstract = {RNA Polymerase II pauses and backtracks during transcription, with many consequences for gene expression and cellular physiology. Here, we show that the energy required to melt double-stranded nucleic acids in the transcription bubble predicts pausing in Saccharomyces cerevisiae far more accurately than nucleosome roadblocks do. In addition, the same energy difference also determines when the RNA polymerase backtracks instead of continuing to move forward. This data-driven model corroborates—in a genome wide and quantitative manner—previous evidence that sequence-dependent thermodynamic features of nucleic acids influence both transcriptional pausing and backtracking.}, author = {Lukacisin, Martin and Landon, Matthieu and Jajoo, Rishi}, issn = {1932-6203}, journal = {PLoS One}, number = {3}, publisher = {Public Library of Science}, title = {{Sequence-specific thermodynamic properties of nucleic acids influence both transcriptional pausing and backtracking in yeast}}, doi = {10.1371/journal.pone.0174066}, volume = {12}, year = {2017}, } @article{1024, abstract = {The history of auxin and cytokinin biology including the initial discoveries by father–son duo Charles Darwin and Francis Darwin (1880), and Gottlieb Haberlandt (1919) is a beautiful demonstration of unceasing continuity of research. Novel findings are integrated into existing hypotheses and models and deepen our understanding of biological principles. At the same time new questions are triggered and hand to hand with this new methodologies are developed to address these new challenges.}, author = {Hurny, Andrej and Benková, Eva}, issn = {1064-3745}, journal = {Auxins and Cytokinins in Plant Biology}, pages = {1 -- 29}, publisher = {Springer}, title = {{Methodological advances in auxin and cytokinin biology}}, doi = {10.1007/978-1-4939-6831-2_1}, volume = {1569}, year = {2017}, } @article{696, abstract = {Mutator strains are expected to evolve when the availability and effect of beneficial mutations are high enough to counteract the disadvantage from deleterious mutations that will inevitably accumulate. As the population becomes more adapted to its environment, both availability and effect of beneficial mutations necessarily decrease and mutation rates are predicted to decrease. It has been shown that certain molecular mechanisms can lead to increased mutation rates when the organism finds itself in a stressful environment. While this may be a correlated response to other functions, it could also be an adaptive mechanism, raising mutation rates only when it is most advantageous. Here, we use a mathematical model to investigate the plausibility of the adaptive hypothesis. We show that such a mechanism can be mantained if the population is subjected to diverse stresses. By simulating various antibiotic treatment schemes, we find that combination treatments can reduce the effectiveness of second-order selection on stress-induced mutagenesis. We discuss the implications of our results to strategies of antibiotic therapy.}, author = {Lukacisinova, Marta and Novak, Sebastian and Paixao, Tiago}, issn = {1553-734X}, journal = {PLoS Computational Biology}, number = {7}, publisher = {Public Library of Science}, title = {{Stress induced mutagenesis: Stress diversity facilitates the persistence of mutator genes}}, doi = {10.1371/journal.pcbi.1005609}, volume = {13}, year = {2017}, } @article{676, abstract = {The segregation of different cell types into distinct tissues is a fundamental process in metazoan development. Differences in cell adhesion and cortex tension are commonly thought to drive cell sorting by regulating tissue surface tension (TST). However, the role that differential TST plays in cell segregation within the developing embryo is as yet unclear. Here, we have analyzed the role of differential TST for germ layer progenitor cell segregation during zebrafish gastrulation. Contrary to previous observations that differential TST drives germ layer progenitor cell segregation in vitro, we show that germ layers display indistinguishable TST within the gastrulating embryo, arguing against differential TST driving germ layer progenitor cell segregation in vivo. We further show that the osmolarity of the interstitial fluid (IF) is an important factor that influences germ layer TST in vivo, and that lower osmolarity of the IF compared with standard cell culture medium can explain why germ layers display differential TST in culture but not in vivo. Finally, we show that directed migration of mesendoderm progenitors is required for germ layer progenitor cell segregation and germ layer formation.}, author = {Krens, Gabriel and Veldhuis, Jim and Barone, Vanessa and Capek, Daniel and Maître, Jean-Léon and Brodland, Wayne and Heisenberg, Carl-Philipp J}, issn = {09501991}, journal = {Development}, number = {10}, pages = {1798 -- 1806}, publisher = {Company of Biologists}, title = {{Interstitial fluid osmolarity modulates the action of differential tissue surface tension in progenitor cell segregation during gastrulation}}, doi = {10.1242/dev.144964}, volume = {144}, year = {2017}, } @article{1027, abstract = {The rising prevalence of antibiotic resistant bacteria is an increasingly serious public health challenge. To address this problem, recent work ranging from clinical studies to theoretical modeling has provided valuable insights into the mechanisms of resistance, its emergence and spread, and ways to counteract it. A deeper understanding of the underlying dynamics of resistance evolution will require a combination of experimental and theoretical expertise from different disciplines and new technology for studying evolution in the laboratory. Here, we review recent advances in the quantitative understanding of the mechanisms and evolution of antibiotic resistance. We focus on key theoretical concepts and new technology that enables well-controlled experiments. We further highlight key challenges that can be met in the near future to ultimately develop effective strategies for combating resistance.}, author = {Lukacisinova, Marta and Bollenbach, Mark Tobias}, journal = {Current Opinion in Biotechnology}, pages = {90 -- 97}, publisher = {Elsevier}, title = {{Toward a quantitative understanding of antibiotic resistance evolution}}, doi = {10.1016/j.copbio.2017.02.013}, volume = {46}, year = {2017}, } @article{661, abstract = {During embryonic development, mechanical forces are essential for cellular rearrangements driving tissue morphogenesis. Here, we show that in the early zebrafish embryo, friction forces are generated at the interface between anterior axial mesoderm (prechordal plate, ppl) progenitors migrating towards the animal pole and neurectoderm progenitors moving in the opposite direction towards the vegetal pole of the embryo. These friction forces lead to global rearrangement of cells within the neurectoderm and determine the position of the neural anlage. Using a combination of experiments and simulations, we show that this process depends on hydrodynamic coupling between neurectoderm and ppl as a result of E-cadherin-mediated adhesion between those tissues. Our data thus establish the emergence of friction forces at the interface between moving tissues as a critical force-generating process shaping the embryo.}, author = {Smutny, Michael and Ákos, Zsuzsa and Grigolon, Silvia and Shamipour, Shayan and Ruprecht, Verena and Capek, Daniel and Behrndt, Martin and Papusheva, Ekaterina and Tada, Masazumi and Hof, Björn and Vicsek, Tamás and Salbreux, Guillaume and Heisenberg, Carl-Philipp J}, issn = {1465-7392}, journal = {Nature Cell Biology}, pages = {306 -- 317}, publisher = {Nature Publishing Group}, title = {{Friction forces position the neural anlage}}, doi = {10.1038/ncb3492}, volume = {19}, year = {2017}, } @article{664, abstract = {Immune cells communicate using cytokine signals, but the quantitative rules of this communication aren't clear. In this issue of Immunity, Oyler-Yaniv et al. (2017) suggest that the distribution of a cytokine within a lymphatic organ is primarily governed by the local density of cells consuming it.}, author = {Assen, Frank P and Sixt, Michael K}, issn = {1074-7613}, journal = {Immunity}, number = {4}, pages = {519 -- 520}, publisher = {Cell Press}, title = {{The dynamic cytokine niche}}, doi = {10.1016/j.immuni.2017.04.006}, volume = {46}, year = {2017}, } @article{679, abstract = {Protective responses against pathogens require a rapid mobilization of resting neutrophils and the timely removal of activated ones. Neutrophils are exceptionally short-lived leukocytes, yet it remains unclear whether the lifespan of pathogen-engaged neutrophils is regulated differently from that in the circulating steady-state pool. Here, we have found that under homeostatic conditions, the mRNA-destabilizing protein tristetraprolin (TTP) regulates apoptosis and the numbers of activated infiltrating murine neutrophils but not neutrophil cellularity. Activated TTP-deficient neutrophils exhibited decreased apoptosis and enhanced accumulation at the infection site. In the context of myeloid-specific deletion of Ttp, the potentiation of neutrophil deployment protected mice against lethal soft tissue infection with Streptococcus pyogenes and prevented bacterial dissemination. Neutrophil transcriptome analysis revealed that decreased apoptosis of TTP-deficient neutrophils was specifically associated with elevated expression of myeloid cell leukemia 1 (Mcl1) but not other antiapoptotic B cell leukemia/ lymphoma 2 (Bcl2) family members. Higher Mcl1 expression resulted from stabilization of Mcl1 mRNA in the absence of TTP. The low apoptosis rate of infiltrating TTP-deficient neutrophils was comparable to that of transgenic Mcl1-overexpressing neutrophils. Our study demonstrates that posttranscriptional gene regulation by TTP schedules the termination of the antimicrobial engagement of neutrophils. The balancing role of TTP comes at the cost of an increased risk of bacterial infections.}, author = {Ebner, Florian and Sedlyarov, Vitaly and Tasciyan, Saren and Ivin, Masa and Kratochvill, Franz and Gratz, Nina and Kenner, Lukas and Villunger, Andreas and Sixt, Michael K and Kovarik, Pavel}, issn = {0021-9738}, journal = {The Journal of Clinical Investigation}, number = {6}, pages = {2051 -- 2065}, publisher = {American Society for Clinical Investigation}, title = {{The RNA-binding protein tristetraprolin schedules apoptosis of pathogen-engaged neutrophils during bacterial infection}}, doi = {10.1172/JCI80631}, volume = {127}, year = {2017}, } @inproceedings{637, abstract = {For many cryptographic primitives, it is relatively easy to achieve selective security (where the adversary commits a-priori to some of the choices to be made later in the attack) but appears difficult to achieve the more natural notion of adaptive security (where the adversary can make all choices on the go as the attack progresses). A series of several recent works shows how to cleverly achieve adaptive security in several such scenarios including generalized selective decryption (Panjwani, TCC ’07 and Fuchsbauer et al., CRYPTO ’15), constrained PRFs (Fuchsbauer et al., ASIACRYPT ’14), and Yao garbled circuits (Jafargholi and Wichs, TCC ’16b). Although the above works expressed vague intuition that they share a common technique, the connection was never made precise. In this work we present a new framework that connects all of these works and allows us to present them in a unified and simplified fashion. Moreover, we use the framework to derive a new result for adaptively secure secret sharing over access structures defined via monotone circuits. We envision that further applications will follow in the future. Underlying our framework is the following simple idea. It is well known that selective security, where the adversary commits to n-bits of information about his future choices, automatically implies adaptive security at the cost of amplifying the adversary’s advantage by a factor of up to 2n. However, in some cases the proof of selective security proceeds via a sequence of hybrids, where each pair of adjacent hybrids locally only requires some smaller partial information consisting of m ≪ n bits. The partial information needed might be completely different between different pairs of hybrids, and if we look across all the hybrids we might rely on the entire n-bit commitment. Nevertheless, the above is sufficient to prove adaptive security, at the cost of amplifying the adversary’s advantage by a factor of only 2m ≪ 2n. In all of our examples using the above framework, the different hybrids are captured by some sort of a graph pebbling game and the amount of information that the adversary needs to commit to in each pair of hybrids is bounded by the maximum number of pebbles in play at any point in time. Therefore, coming up with better strategies for proving adaptive security translates to various pebbling strategies for different types of graphs.}, author = {Jafargholi, Zahra and Kamath Hosdurg, Chethan and Klein, Karen and Komargodski, Ilan and Pietrzak, Krzysztof Z and Wichs, Daniel}, editor = {Katz, Jonathan and Shacham, Hovav}, isbn = {978-331963687-0}, location = {Santa Barbara, CA, United States}, pages = {133 -- 163}, publisher = {Springer}, title = {{Be adaptive avoid overcommitting}}, doi = {10.1007/978-3-319-63688-7_5}, volume = {10401}, year = {2017}, } @article{960, abstract = {The human cerebral cortex is the seat of our cognitive abilities and composed of an extraordinary number of neurons, organized in six distinct layers. The establishment of specific morphological and physiological features in individual neurons needs to be regulated with high precision. Impairments in the sequential developmental programs instructing corticogenesis lead to alterations in the cortical cytoarchitecture which is thought to represent the major underlying cause for several neurological disorders including neurodevelopmental and psychiatric diseases. In this review we discuss the role of cell polarity at sequential stages during cortex development. We first provide an overview of morphological cell polarity features in cortical neural stem cells and newly-born postmitotic neurons. We then synthesize a conceptual molecular and biochemical framework how cell polarity is established at the cellular level through a break in symmetry in nascent cortical projection neurons. Lastly we provide a perspective how the molecular mechanisms applying to single cells could be probed and integrated in an in vivo and tissue-wide context.}, author = {Hansen, Andi H and Düllberg, Christian F and Mieck, Christine and Loose, Martin and Hippenmeyer, Simon}, issn = {1662-5102}, journal = {Frontiers in Cellular Neuroscience}, publisher = {Frontiers Research Foundation}, title = {{Cell polarity in cerebral cortex development - cellular architecture shaped by biochemical networks}}, doi = {10.3389/fncel.2017.00176}, volume = {11}, year = {2017}, } @inproceedings{949, abstract = {The notion of treewidth of graphs has been exploited for faster algorithms for several problems arising in verification and program analysis. Moreover, various notions of balanced tree decompositions have been used for improved algorithms supporting dynamic updates and analysis of concurrent programs. In this work, we present a tool for constructing tree-decompositions of CFGs obtained from Java methods, which is implemented as an extension to the widely used Soot framework. The experimental results show that our implementation on real-world Java benchmarks is very efficient. Our tool also provides the first implementation for balancing tree-decompositions. In summary, we present the first tool support for exploiting treewidth in the static analysis problems on Java programs.}, author = {Chatterjee, Krishnendu and Goharshady, Amir and Pavlogiannis, Andreas}, editor = {D'Souza, Deepak}, issn = {03029743}, location = {Pune, India}, pages = {59 -- 66}, publisher = {Springer}, title = {{JTDec: A tool for tree decompositions in soot}}, doi = {10.1007/978-3-319-68167-2_4}, volume = {10482}, year = {2017}, } @inproceedings{639, abstract = {We study the problem of developing efficient approaches for proving worst-case bounds of non-deterministic recursive programs. Ranking functions are sound and complete for proving termination and worst-case bounds of non-recursive programs. First, we apply ranking functions to recursion, resulting in measure functions, and show that they provide a sound and complete approach to prove worst-case bounds of non-deterministic recursive programs. Our second contribution is the synthesis of measure functions in non-polynomial forms. We show that non-polynomial measure functions with logarithm and exponentiation can be synthesized through abstraction of logarithmic or exponentiation terms, Farkas’ Lemma, and Handelman’s Theorem using linear programming. While previous methods obtain worst-case polynomial bounds, our approach can synthesize bounds of the form O(n log n) as well as O(nr) where r is not an integer. We present experimental results to demonstrate that our approach can efficiently obtain worst-case bounds of classical recursive algorithms such as Merge-Sort, Closest-Pair, Karatsuba’s algorithm and Strassen’s algorithm.}, author = {Chatterjee, Krishnendu and Fu, Hongfei and Goharshady, Amir}, editor = {Majumdar, Rupak and Kunčak, Viktor}, isbn = {978-331963389-3}, location = {Heidelberg, Germany}, pages = {41 -- 63}, publisher = {Springer}, title = {{Non-polynomial worst case analysis of recursive programs}}, doi = {10.1007/978-3-319-63390-9_3}, volume = {10427}, year = {2017}, } @inproceedings{1001, abstract = {We present a computational approach for designing CurveUps, curvy shells that form from an initially flat state. They consist of small rigid tiles that are tightly held together by two pre-stretched elastic sheets attached to them. Our method allows the realization of smooth, doubly curved surfaces that can be fabricated as a flat piece. Once released, the restoring forces of the pre-stretched sheets support the object to take shape in 3D. CurveUps are structurally stable in their target configuration. The design process starts with a target surface. Our method generates a tile layout in 2D and optimizes the distribution, shape, and attachment areas of the tiles to obtain a configuration that is fabricable and in which the curved up state closely matches the target. Our approach is based on an efficient approximate model and a local optimization strategy for an otherwise intractable nonlinear optimization problem. We demonstrate the effectiveness of our approach for a wide range of shapes, all realized as physical prototypes.}, author = {Guseinov, Ruslan and Miguel, Eder and Bickel, Bernd}, location = {Los Angeles, CA, United States}, number = {4}, publisher = {ACM}, title = {{CurveUps: Shaping objects from flat plates with tension-actuated curvature}}, doi = {10.1145/3072959.3073709}, volume = {36}, year = {2017}, } @article{1120, abstract = {The existence of a self-localization transition in the polaron problem has been under an active debate ever since Landau suggested it 83 years ago. Here we reveal the self-localization transition for the rotational analogue of the polaron -- the angulon quasiparticle. We show that, unlike for the polarons, self-localization of angulons occurs at finite impurity-bath coupling already at the mean-field level. The transition is accompanied by the spherical-symmetry breaking of the angulon ground state and a discontinuity in the first derivative of the ground-state energy. Moreover, the type of the symmetry breaking is dictated by the symmetry of the microscopic impurity-bath interaction, which leads to a number of distinct self-localized states. The predicted effects can potentially be addressed in experiments on cold molecules trapped in superfluid helium droplets and ultracold quantum gases, as well as on electronic excitations in solids and Bose-Einstein condensates. }, author = {Li, Xiang and Seiringer, Robert and Lemeshko, Mikhail}, issn = {2469-9926}, journal = {Physical Review A}, number = {3}, publisher = {American Physical Society}, title = {{Angular self-localization of impurities rotating in a bosonic bath}}, doi = {10.1103/PhysRevA.95.033608}, volume = {95}, year = {2017}, }