TY - JOUR AB - Steering a quantum harmonic oscillator state along cyclic trajectories leads to a path-dependent geometric phase. Here we describe its experimental observation in an electronic harmonic oscillator. We use a superconducting qubit as a nonlinear probe of the phase, which is otherwise unobservable due to the linearity of the oscillator. We show that the geometric phase is, for a variety of cyclic paths, proportional to the area enclosed in the quadrature plane. At the transition to the nonadiabatic regime, we study corrections to the phase and dephasing of the qubit caused by qubit-resonator entanglement. In particular, we identify parameters for which this dephasing mechanism is negligible even in the nonadiabatic regime. The demonstrated controllability makes our system a versatile tool to study geometric phases in open quantum systems and to investigate their potential for quantum information processing. AU - Pechal, M AU - Berger, Stefan T AU - Abdumalikov, Abdufarrukh A AU - Johannes Fink AU - Mlynek, Jonas A AU - Steffen, L. Kraig AU - Wallraff, Andreas AU - Filipp, Stefan ID - 1782 IS - 17 JF - Physical Review Letters TI - Geometric phase and nonadiabatic effects in an electronic harmonic oscillator VL - 108 ER - TY - JOUR AB - A localized qubit entangled with a propagating quantum field is well suited to study nonlocal aspects of quantum mechanics and may also provide a channel to communicate between spatially separated nodes in a quantum network. Here, we report the on-demand generation and characterization of Bell-type entangled states between a superconducting qubit and propagating microwave fields composed of zero-, one-, and two-photon Fock states. Using low noise linear amplification and efficient data acquisition we extract all relevant correlations between the qubit and the photon states and demonstrate entanglement with high fidelity. AU - Eichler, Christopher AU - Lang, C AU - Johannes Fink AU - Govenius, J AU - Filipp, Stefan AU - Wallraff, Andreas ID - 1784 IS - 24 JF - Physical Review Letters TI - Observation of entanglement between itinerant microwave photons and a superconducting qubit VL - 109 ER - TY - JOUR AB - Brain circuits are assembled from a large variety of morphologically and functionally diverse cell types. It is not known how the intermingled cell types of an individual adult brain region differ in their expressed genomes. Here we describe an atlas of cell type transcriptomes in one brain region, the mouse retina. We found that each adult cell type expressed a specific set of genes, including a unique set of transcription factors, forming a 'barcode' for cell identity. Cell type transcriptomes carried enough information to categorize cells into morphological classes and types. Several genes that were specifically expressed in particular retinal circuit elements, such as inhibitory neuron types, are associated with eye diseases. The resource described here allows gene expression to be compared across adult retinal cell types, experimenting with specific transcription factors to differentiate stem or somatic cells to retinal cell types, and predicting cellular targets of newly discovered disease-associated genes. AU - Sandra Siegert AU - Cabuy, Erik AU - Scherf, Brigitte G AU - Kohler, Hubertus AU - Panda, Satchidananda AU - Le, Yunzheng AU - Fehling, Hans J AU - Gaidatzis, Dimos AU - Stadler, Michael B AU - Roska, Botond M ID - 1801 IS - 3 JF - Nature Neuroscience TI - Transcriptional code and disease map for adult retinal cell types VL - 15 ER - TY - GEN AB - Complex I is a key enzyme of the respiratory chain in many organisms. This multi-protein complex with an intricate evolutionary history originated from the unification of prebuilt modules of hydrogenases and transporters. Using recently determined crystallographic structures of complex I we reanalyzed evolutionarily related complexes that couple oxidoreduction to trans-membrane ion translocation. Our analysis points to the previously unnoticed structural homology of the electron input module of formate dehydrogenlyases and subunit NuoG of complex I. We also show that all related to complex I hydrogenases likely operate via a conformation driven mechanism with structural changes generated in the conserved coupling site located at the interface of subunits NuoB/D/H. The coupling apparently originated once in evolutionary history, together with subunit NuoH joining hydrogenase and transport modules. Analysis of quinone oxidoreduction properties and the structure of complex I allows us to suggest a fully reversible coupling mechanism. Our model predicts that: 1) proton access to the ketone groups of the bound quinone is rigorously controlled by the protein, 2) the negative electric charge of the anionic ubiquinol head group is a major driving force for conformational changes. AU - Efremov, Rouslan G AU - Leonid Sazanov ID - 1976 IS - 10 T2 - Biochimica et Biophysica Acta - Bioenergetics TI - The coupling mechanism of respiratory complex i - A structural and evolutionary perspective VL - 1817 ER - TY - JOUR AB - Outer membrane protein F, a major component of the Escherichia coli outer membrane, was crystallized for the first time in lipidic mesophase of monoolein in novel space groups, P1 and H32. Due to ease of its purification and crystallization OmpF can be used as a benchmark protein for establishing membrane protein crystallization in meso, as a "membrane lyzozyme" The packing of porin trimers in the crystals of space group H32 is similar to natural outer membranes, providing the first high-resolution insight into the close to native packing of OmpF. Surprisingly, interaction between trimers is mediated exclusively by lipids, without direct protein-protein contacts. Multiple ordered lipids are observed and many of them occupy identical positions independently of the space group, identifying preferential interaction sites of lipid acyl chains. Presence of ordered aliphatic chains close to a positively charged area on the porin surface suggests a position for a lipopolysaccharide binding site on the surface of the major E. coli porins. AU - Efremov, Rouslan G AU - Leonid Sazanov ID - 1972 IS - 3 JF - Journal of Structural Biology TI - Structure of Escherichia coli OmpF porin from lipidic mesophase VL - 178 ER - TY - JOUR AB - In the living cell, proteins are able to organize space much larger than their dimensions. In return, changes of intracellular space can influence biochemical reactions, allowing cells to sense their size and shape. Despite the possibility to reconstitute protein self-organization with only a few purified components, we still lack knowledge of how geometrical boundaries affect spatiotemporal protein patterns. Following a minimal systems approach, we used purified proteins and photolithographically patterned membranes to study the influence of spatial confinement on the self-organization of the Min system, a spatial regulator of bacterial cytokinesis, in vitro. We found that the emerging protein pattern responds even to the lateral, two-dimensional geometry of the membrane such that, as in the three-dimensional cell, Min protein waves travel along the longest axis of the membrane patch. This shows that for spatial sensing the Min system does not need to be enclosed in a three-dimensional compartment. Using a computational model we quantitatively analyzed our experimental findings and identified persistent binding of MinE to the membrane as requirement for the Min system to sense geometry. Our results give insight into the interplay between geometrical confinement and biochemical patterns emerging from a nonlinear reaction-diffusion system. AU - Schweizer, Jakob AU - Martin Loose AU - Bonny, Mike AU - Kruse, Karsten AU - Mönch, Ingolf AU - Schwille, Petra ID - 1987 IS - 38 JF - PNAS TI - Geometry sensing by self-organized protein patterns VL - 109 ER - TY - CONF AB - Leakage resilient cryptography attempts to incorporate side-channel leakage into the black-box security model and designs cryptographic schemes that are provably secure within it. Informally, a scheme is leakage-resilient if it remains secure even if an adversary learns a bounded amount of arbitrary information about the schemes internal state. Unfortunately, most leakage resilient schemes are unnecessarily complicated in order to achieve strong provable security guarantees. As advocated by Yu et al. [CCS’10], this mostly is an artefact of the security proof and in practice much simpler construction may already suffice to protect against realistic side-channel attacks. In this paper, we show that indeed for simpler constructions leakage-resilience can be obtained when we aim for relaxed security notions where the leakage-functions and/or the inputs to the primitive are chosen non-adaptively. For example, we show that a three round Feistel network instantiated with a leakage resilient PRF yields a leakage resilient PRP if the inputs are chosen non-adaptively (This complements the result of Dodis and Pietrzak [CRYPTO’10] who show that if a adaptive queries are allowed, a superlogarithmic number of rounds is necessary.) We also show that a minor variation of the classical GGM construction gives a leakage resilient PRF if both, the leakage-function and the inputs, are chosen non-adaptively. AU - Faust, Sebastian AU - Pietrzak, Krzysztof Z AU - Schipper, Joachim ID - 2048 T2 - Conference proceedings CHES 2012 TI - Practical leakage-resilient symmetric cryptography VL - 7428 ER - TY - CONF AB - We propose a new authentication protocol that is provably secure based on a ring variant of the learning parity with noise (LPN) problem. The protocol follows the design principle of the LPN-based protocol from Eurocrypt’11 (Kiltz et al.), and like it, is a two round protocol secure against active attacks. Moreover, our protocol has small communication complexity and a very small footprint which makes it applicable in scenarios that involve low-cost, resource-constrained devices. Performance-wise, our protocol is more efficient than previous LPN-based schemes, such as the many variants of the Hopper-Blum (HB) protocol and the aforementioned protocol from Eurocrypt’11. Our implementation results show that it is even comparable to the standard challenge-and-response protocols based on the AES block-cipher. Our basic protocol is roughly 20 times slower than AES, but with the advantage of having 10 times smaller code size. Furthermore, if a few hundred bytes of non-volatile memory are available to allow the storage of some off-line pre-computations, then the online phase of our protocols is only twice as slow as AES. AU - Heyse, Stefan AU - Kiltz, Eike AU - Lyubashevsky, Vadim AU - Paar, Christof AU - Pietrzak, Krzysztof Z ID - 2049 T2 - Conference proceedings FSE 2012 TI - Lapin: An efficient authentication protocol based on ring-LPN VL - 7549 ER - TY - JOUR AB - Background: Drosophila albomicans is a unique model organism for studying both sex chromosome and B chromosome evolution. A pair of its autosomes comprising roughly 40% of the whole genome has fused to the ancient X and Y chromosomes only about 0.12 million years ago, thereby creating the youngest and most gene-rich neo-sex system reported to date. This species also possesses recently derived B chromosomes that show non-Mendelian inheritance and significantly influence fertility.Methods: We sequenced male flies with B chromosomes at 124.5-fold genome coverage using next-generation sequencing. To characterize neo-Y specific changes and B chromosome sequences, we also sequenced inbred female flies derived from the same strain but without B's at 28.5-fold.Results: We assembled a female genome and placed 53% of the sequence and 85% of the annotated proteins into specific chromosomes, by comparison with the 12 Drosophila genomes. Despite its very recent origin, the non-recombining neo-Y chromosome shows various signs of degeneration, including a significant enrichment of non-functional genes compared to the neo-X, and an excess of tandem duplications relative to other chromosomes. We also characterized a B-chromosome linked scaffold that contains an actively transcribed unit and shows sequence similarity to the subcentromeric regions of both the ancient X and the neo-X chromosome.Conclusions: Our results provide novel insights into the very early stages of sex chromosome evolution and B chromosome origination, and suggest an unprecedented connection between the births of these two systems in D. albomicans. AU - Zhou, Qi AU - Zhu, Hongmei AU - Huang, Quanfei AU - Zhao, Li AU - Zhang, Guo J AU - Roy, Scott W AU - Beatriz Vicoso AU - Xuan, Zhaolin AU - Ruan, Jue AU - Zhang, Yue AU - Zhao, Ruoping AU - Ye, Chen AU - Zhang, Xiuqing AU - Wang, Jùn AU - Wang, Wen AU - Bachtrog, Doris ID - 2073 IS - 1 JF - BMC Genomics TI - Deciphering neo-sex and B chromosome evolution by the draft genome of Drosophila albomicans VL - 13 ER - TY - JOUR AB - We introduce an algorithm and representation for fabricating 3D shape abstractions using mutually intersecting planar cut-outs. The planes have prefabricated slits at their intersections and are assembled by sliding them together. Often such abstractions are used as a sculptural art form or in architecture and are colloquially called ‘cardboard sculptures’. Based on an analysis of construction rules, we propose an extended binary space partitioning tree as an efficient representation of such cardboard models which allows us to quickly evaluate the feasibility of newly added planar elements. The complexity of insertion order quickly increases with the number of planar elements and manual analysis becomes intractable. We provide tools for generating cardboard sculptures with guaranteed constructibility. In combination with a simple optimization and sampling strategy for new elements, planar shape abstraction models can be designed by iteratively adding elements. As an output, we obtain a fabrication plan that can be printed or sent to a laser cutter. We demonstrate the complete process by designing and fabricating cardboard models of various well-known 3D shapes. AU - Hildebrand, Kristian AU - Bernd Bickel AU - Alexa, Marc ID - 2079 IS - 2pt3 JF - Computer Graphics Forum TI - crdbrd: Shape fabrication by sliding planar slices VL - 31 ER - TY - JOUR AB - Although facial hair plays an important role in individual expression, facial-hair reconstruction is not addressed by current facecapture systems. Our research addresses this limitation with an algorithm that treats hair and skin surface capture together in a coupled fashion so that a high-quality representation of hair fibers as well as the underlying skin surface can be reconstructed. We propose a passive, camera-based system that is robust against arbitrary motion since all data is acquired within the time period of a single exposure. Our reconstruction algorithm detects and traces hairs in the captured images and reconstructs them in 3D using a multiview stereo approach. Our coupled skin-reconstruction algorithm uses information about the detected hairs to deliver a skin surface that lies underneath all hairs irrespective of occlusions. In dense regions like eyebrows, we employ a hair-synthesis method to create hair fibers that plausibly match the image data. We demonstrate our scanning system on a number of individuals and show that it can successfully reconstruct a variety of facial-hair styles together with the underlying skin surface. AU - Beeler, Thabo AU - Bernd Bickel AU - Noris, Gioacchino AU - Beardsley, Paul A AU - Marschner, Steve AU - Sumner, Robert W AU - Groß, Markus S ID - 2103 IS - 4 JF - ACM Transactions on Graphics TI - Coupled 3D reconstruction of sparse facial hair and skin VL - 31 ER - TY - JOUR AB - Articulated deformable characters are widespread in computer animation. Unfortunately, we lack methods for their automatic fabrication using modern additive manufacturing (AM) technologies. We propose a method that takes a skinned mesh as input, then estimates a fabricatable single-material model that approximates the 3D kinematics of the corresponding virtual articulated character in a piecewise linear manner. We first extract a set of potential joint locations. From this set, together with optional, user-specified range constraints, we then estimate mechanical friction joints that satisfy inter-joint non-penetration and other fabrication constraints. To avoid brittle joint designs, we place joint centers on an approximate medial axis representation of the input geometry, and maximize each joint's minimal cross-sectional area. We provide several demonstrations, manufactured as single, assembled pieces using 3D printers. AU - Bac̈her, Moritz AU - Bernd Bickel AU - James, Doug L AU - Pfister, Hanspeter ID - 2101 IS - 4 JF - ACM Transactions on Graphics TI - Fabricating articulated characters from skinned meshes VL - 31 ER - TY - JOUR AB - We propose a complete process for designing, simulating, and fabricating synthetic skin for an animatronics character that mimics the face of a given subject and its expressions. The process starts with measuring the elastic properties of a material used to manufacture synthetic soft tissue. Given these measurements we use physicsbased simulation to predict the behavior of a face when it is driven by the underlying robotic actuation. Next, we capture 3D facial expressions for a given target subject. As the key component of our process, we present a novel optimization scheme that determines the shape of the synthetic skin as well as the actuation parameters that provide the best match to the target expressions. We demonstrate this computational skin design by physically cloning a real human face onto an animatronics figure. AU - Bernd Bickel AU - Kaufmann, Peter AU - Skouras, Mélina AU - Thomaszewski, Bernhard AU - Bradley, Derek J AU - Beeler, Thabo AU - Jackson, Philip V AU - Marschner, Steve AU - Matusik, Wojciech AU - Groß, Markus S ID - 2102 IS - 4 JF - ACM Transactions on Graphics TI - Physical face cloning VL - 31 ER - TY - CONF AB - Progress in cloth simulation for computer animation and apparel design has led to a multitude of deformation models, each with its own way of relating geometry, deformation, and forces. As simulators improve, differences between these models become more important, but it is difficult to choose a model and a set of parameters to match a given real material simply by looking at simulation results. This paper provides measurement and fitting methods that allow nonlinear models to be fit to the observed deformation of a particular cloth sample. Unlike standard textile testing, our system measures complex 3D deformations of a sheet of cloth, not just one-dimensional force-displacement curves, so it works under a wider range of deformation conditions. The fitted models are then evaluated by comparison to measured deformations with motions very different from those used for fitting. AU - Miguel, Eder AU - Bradley, Derek J AU - Thomaszewski, Bernhard AU - Bernd Bickel AU - Matusik, Wojciech AU - Otaduy, Miguel A AU - Marschner, Steve ID - 2106 IS - 2 TI - Data-driven estimation of cloth simulation models VL - 31 ER - TY - CONF AB - In recent years, various methods have been introduced to exploit pre-recorded data to improve the performance and/or realism of dynamic deformations, but their differences and similarities have not been adequately analyzed or discussed. So far, the proposed methods have been explored mainly in the research context. They have not been adopted by the computer graphics industry. This course bridges the gap between research labs and industry to present a unifying theory and understanding of data-driven methods for dynamic deformations that may inspire development of novel solutions. It focuses on application of data-driven methods to three areas of computer animation: dynamic deformation of faces, soft volumetric tissue, and cloth. And it describes how to approach these challenges in a data-driven manner, classifies the various methods, and demonstrates how data-driven methods can work in other settings. AU - Otaduy, Miguel A AU - Bernd Bickel AU - Bradley, Derek J AU - Wang, Huamin ID - 2104 TI - Data-driven simulation methods in computer graphics: Cloth, tissue and faces ER - TY - CONF AU - Skouras, Mélina AU - Thomaszewski, Bernhard AU - Bernd Bickel AU - Groß, Markus S ID - 2105 IS - 2 TI - Computational design of rubber balloons VL - 31 ER - TY - JOUR AB - We consider a class of stochastic PDEs of Burgers type in spatial dimension 1, driven by space–time white noise. Even though it is well known that these equations are well posed, it turns out that if one performs a spatial discretization of the nonlinearity in the “wrong” way, then the sequence of approximate equations does converge to a limit, but this limit exhibits an additional correction term. This correction term is proportional to the local quadratic cross-variation (in space) of the gradient of the conserved quantity with the solution itself. This can be understood as a consequence of the fact that for any fixed time, the law of the solution is locally equivalent to Wiener measure, where space plays the role of time. In this sense, the correction term is similar to the usual Itô–Stratonovich correction term that arises when one considers different temporal discretizations of stochastic ODEs. AU - Hairer, Martin M AU - Jan Maas ID - 2125 IS - 4 JF - Annals of Probability TI - A spatial version of the Itô-Stratonovich correction VL - 40 ER - TY - JOUR AB - We study a new notion of Ricci curvature that applies to Markov chains on discrete spaces. This notion relies on geodesic convexity of the entropy and is analogous to the one introduced by Lott, Sturm, and Villani for geodesic measure spaces. In order to apply to the discrete setting, the role of the Wasserstein metric is taken over by a different metric, having the property that continuous time Markov chains are gradient flows of the entropy. Using this notion of Ricci curvature we prove discrete analogues of fundamental results by Bakry–Émery and Otto–Villani. Further, we show that Ricci curvature bounds are preserved under tensorisation. As a special case we obtain the sharp Ricci curvature lower bound for the discrete hypercube. AU - Erbar, Matthias AU - Jan Maas ID - 2127 IS - 3 JF - Archive for Rational Mechanics and Analysis TI - Ricci curvature of finite Markov chains via convexity of the entropy VL - 206 ER - TY - JOUR AB - We introduce a technique for handling Whitney decompositions in Gaussian harmonic analysis and apply it to the study of Gaussian analogues of the classical tent spaces T 1,q of Coifman–Meyer–Stein. AU - Jan Maas AU - van Neerven, Jan M AU - Portal, Pierre ID - 2128 IS - 2 JF - Arkiv för Matematik TI - Whitney coverings and the tent spaces T 1,q (γ) for the Gaussian measure VL - 50 ER - TY - JOUR AB - We show that the electric dipole-dipole interaction between a pair of polar molecules undergoes an all-out transformation when superimposed by a far-off-resonant optical field. The combined interaction potential becomes tunable by variation of wavelength, polarisation and intensity of the optical field and its dependence on the intermolecular separation exhibits a crossover from an inverse-power to an oscillating behaviour. The ability thereby offered to control molecular interactions opens up avenues toward the creation and manipulation of novel phases of ultracold polar gases among whose characteristics is a long-range entanglement of the dipoles' mutual orientation. We devised an accurate analytic model of such optical-field-dressed dipole-dipole interaction potentials, which enables a straightforward access to the optical-field parameters required for the design of intermolecular interactions in the laboratory. AU - Mikhail Lemeshko AU - Friedrich, Břetislav ID - 2203 IS - 15-16 JF - Molecular Physics TI - Interaction between polar molecules subject to a far-off-resonant optical field: Entangled dipoles up- or down-holding each other VL - 110 ER -