@article{101,
abstract = {Majorana zero modes are quasiparticle excitations in condensed matter systems that have been proposed as building blocks of fault-tolerant quantum computers. They are expected to exhibit non-Abelian particle statistics, in contrast to the usual statistics of fermions and bosons, enabling quantum operations to be performed by braiding isolated modes around one another. Quantum braiding operations are topologically protected insofar as these modes are pinned near zero energy, with the departure from zero expected to be exponentially small as the modes become spatially separated. Following theoretical proposals, several experiments have identified signatures of Majorana modes in nanowires with proximity-induced superconductivity and atomic chains, with small amounts of mode splitting potentially explained by hybridization of Majorana modes. Here, we use Coulomb-blockade spectroscopy in an InAs nanowire segment with epitaxial aluminium, which forms a proximity-induced superconducting Coulomb island (a â ∼ Majorana islandâ (tm)) that is isolated from normal-metal leads by tunnel barriers, to measure the splitting of near-zero-energy Majorana modes. We observe exponential suppression of energy splitting with increasing wire length. For short devices of a few hundred nanometres, sub-gap state energies oscillate as the magnetic field is varied, as is expected for hybridized Majorana modes. Splitting decreases by a factor of about ten for each half a micrometre of increased wire length. For devices longer than about one micrometre, transport in strong magnetic fields occurs through a zero-energy state that is energetically isolated from a continuum, yielding uniformly spaced Coulomb-blockade conductance peaks, consistent with teleportation via Majorana modes. Our results help to explain the trivial-to-topological transition in finite systems and to quantify the scaling of topological protection with end-mode separation.},
author = {Albrecht, S M and Higginbotham, Andrew P and Jespersen, Thomas and Madsen, Morten and Kuemmeth, Ferdinand and Nygård, Jesper and Krogstrup, Peter and Marcus, Charles},
journal = {Nature},
number = {7593},
pages = {206 -- 209},
publisher = {Nature Publishing Group},
title = {{Exponential protection of zero modes in Majorana islands}},
doi = {10.1038/nature17162},
volume = {531},
year = {2016},
}
@article{102,
abstract = {Recent experiments have produced mounting evidence of Majorana zero modes in nanowire-superconductor hybrids. Signatures of an expected topological phase transition accompanying the onset of these modes nevertheless remain elusive. We investigate a fundamental question concerning this issue: Do well-formed Majorana modes necessarily entail a sharp phase transition in these setups? Assuming reasonable parameters, we argue that finite-size effects can dramatically smooth this putative transition into a crossover, even in systems large enough to support well-localized Majorana modes. We propose overcoming such finite-size effects by examining the behavior of low-lying excited states through tunneling spectroscopy. In particular, the excited-state energies exhibit characteristic field and density dependence, and scaling with system size, that expose an approaching topological phase transition. We suggest several experiments for extracting the predicted behavior. As a useful byproduct, the protocols also allow one to measure the wire's spin-orbit coupling directly in its superconducting environment.},
author = {Mishmash, Ryan and Aasen, David and Higginbotham, Andrew P and Alicea, Jason},
journal = {Physical Review B},
number = {24},
publisher = {American Physical Society},
title = {{Approaching a topological phase transition in Majorana nanowires}},
doi = {10.1103/PhysRevB.93.245404},
volume = {93},
year = {2016},
}
@article{1057,
abstract = {Far-field super-resolution fluorescence microscopy discerns fluorophores residing closer than the diffraction barrier by briefly transferring them in different (typically ON and OFF) states before detection. In coordinate-targeted super-resolution variants, such as stimulated emission depletion (STED) microscopy, this state difference is created by the intensity minima and maxima of an optical pattern, causing all fluorophores to assume the off state, for instance, except at the minima. Although strong spatial confinement of the on state enables high resolution, it also subjects the fluorophores to excess intensities and state cycles at the maxima. Here, we address these issues by driving the fluorophores into a second off state that is inert to the excess light. By using reversibly switchable fluorescent proteins as labels, our approach reduces bleaching and enhances resolution and contrast in live-cell STED microscopy. Using two or more transitions to off states is a useful strategy for augmenting the power of coordinate-targeted super-resolution microscopy.},
author = {Danzl, Johann G and Sidenstein, Sven and Gregor, Carola and Urban, Nicolai and Ilgen, Peter and Jakobs, Stefan and Hell, Stefan},
journal = {Nature Photonics},
number = {2},
pages = {122 -- 128},
publisher = {Nature Publishing Group},
title = {{Coordinate-targeted fluorescence nanoscopy with multiple off states}},
doi = {10.1038/nphoton.2015.266},
volume = {10},
year = {2016},
}
@article{1059,
abstract = {A range of bright and photostable rhodamines and carbopyronines with absorption maxima in the range of λ=500-630 nm were prepared, and enabled the specific labeling of cytoskeletal filaments using HaloTag technology followed by staining with 1 μm solutions of the dye-ligand conjugates. The synthesis, photophysical parameters, fluorogenic behavior, and structure-property relationships of the new dyes are discussed. Light microscopy with stimulated emission depletion (STED) provided one- and two-color images of living cells with an optical resolution of 40-60 nm.},
author = {Butkevich, Alexey and Mitronova, Gyuzel and Sidenstein, Sven and Klocke, Jessica and Kamin, Dirk and Meineke, Dirk and D'Este, Elisa and Kraemer, Philip and Danzl, Johann G and Belov, Vladimir and Hell, Stefan},
journal = {Angewandte Chemie - International Edition},
number = {10},
pages = {3290 -- 3294},
publisher = {Wiley-Blackwell},
title = {{Fluorescent rhodamines and fluorogenic carbopyronines for super-resolution STED microscopy in living cells}},
doi = {10.1002/anie.201511018},
volume = {55},
year = {2016},
}
@article{1060,
abstract = {Superresolution fluorescence microscopy of multiple fluorophores still requires development. Here we present simultaneous three-colour stimulated emission depletion (STED) nanoscopy relying on a single STED beam at 620 nm. Toggling the STED beam between two or more power levels ("multilevelSTEDv) optimizes resolution and contrast in all colour channels, which are intrinsically co-aligned and well separated. Three-colour recording is demonstrated by imaging the nanoscale cytoskeletal organization in cultured hippocampal neurons. The down to ∼35 nm resolution identified periodic actin/betaII spectrin lattices along dendrites and spines; however, at presynaptic and postsynaptic sites, these patterns were found to be absent. Both our multicolour scheme and the 620 nm STED line should be attractive for routine STED microscopy applications.},
author = {Sidenstein, Sven and D'Este, Elisa and Böhm, Marvin and Danzl, Johann G and Belov, Vladimir and Hell, Stefan},
journal = {Scientific Reports},
pages = {1 -- 8},
publisher = {Nature Publishing Group},
title = {{Multicolour multilevel STED nanoscopy of actin/spectrin organization at synapses}},
doi = {10.1038/srep26725},
volume = {6},
year = {2016},
}
@inproceedings{1068,
abstract = {Games on graphs provide the appropriate framework to study several central problems in computer science, such as verification and synthesis of reactive systems. One of the most basic objectives for games on graphs is the liveness (or Büchi) objective that given a target set of vertices requires that some vertex in the target set is visited infinitely often. We study generalized Büchi objectives (i.e., conjunction of liveness objectives), and implications between two generalized Büchi objectives (known as GR(1) objectives), that arise in numerous applications in computer-aided verification. We present improved algorithms and conditional super-linear lower bounds based on widely believed assumptions about the complexity of (A1) combinatorial Boolean matrix multiplication and (A2) CNF-SAT. We consider graph games with n vertices, m edges, and generalized Büchi objectives with k conjunctions. First, we present an algorithm with running time O(k*n^2), improving the previously known O(k*n*m) and O(k^2*n^2) worst-case bounds. Our algorithm is optimal for dense graphs under (A1). Second, we show that the basic algorithm for the problem is optimal for sparse graphs when the target sets have constant size under (A2). Finally, we consider GR(1) objectives, with k_1 conjunctions in the antecedent and k_2 conjunctions in the consequent, and present an O(k_1 k_2 n^{2.5})-time algorithm, improving the previously known O(k_1*k_2*n*m)-time algorithm for m > n^{1.5}. },
author = {Chatterjee, Krishnendu and Dvorák, Wolfgang and Henzinger, Monika and Loitzenbauer, Veronika},
location = {Krakow, Poland},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
title = {{Conditionally optimal algorithms for generalized Büchi Games}},
doi = {10.4230/LIPIcs.MFCS.2016.25},
volume = {58},
year = {2016},
}
@inproceedings{1069,
abstract = {The Continuous Skolem Problem asks whether a real-valued function satisfying a linear differen-
tial equation has a zero in a given interval of real numbers. This is a fundamental reachability
problem for continuous linear dynamical systems, such as linear hybrid automata and continuous-
time Markov chains. Decidability of the problem is currently open – indeed decidability is open
even for the sub-problem in which a zero is sought in a bounded interval. In this paper we show
decidability of the bounded problem subject to Schanuel’s Conjecture, a unifying conjecture in
transcendental number theory. We furthermore analyse the unbounded problem in terms of the
frequencies of the differential equation, that is, the imaginary parts of the characteristic roots.
We show that the unbounded problem can be reduced to the bounded problem if there is at most
one rationally linearly independent frequency, or if there are two rationally linearly independent
frequencies and all characteristic roots are simple. We complete the picture by showing that de-
cidability of the unbounded problem in the case of two (or more) rationally linearly independent
frequencies would entail a major new effectiveness result in Diophantine approximation, namely
computability of the Diophantine-approximation types of all real algebraic numbers.},
author = {Chonev, Ventsislav K and Ouaknine, Joël and Worrell, James},
location = {Rome, Italy},
publisher = {Schloss Dagstuhl- Leibniz-Zentrum fur Informatik},
title = {{On the skolem problem for continuous linear dynamical systems}},
doi = {10.4230/LIPIcs.ICALP.2016.100},
volume = {55},
year = {2016},
}
@inproceedings{1070,
abstract = {We present a logic that extends CTL (Computation Tree Logic) with operators that express synchronization properties. A property is synchronized in a system if it holds in all paths of a certain length. The new logic is obtained by using the same path quantifiers and temporal operators as in CTL, but allowing a different order of the quantifiers. This small syntactic variation induces a logic that can express non-regular properties for which known extensions of MSO with equality of path length are undecidable. We show that our variant of CTL is decidable and that the model-checking problem is in Delta_3^P = P^{NP^NP}, and is DP-hard. We analogously consider quantifier exchange in extensions of CTL, and we present operators defined using basic operators of CTL* that express the occurrence of infinitely many synchronization points. We show that the model-checking problem remains in Delta_3^P. The distinguishing power of CTL and of our new logic coincide if the Next operator is allowed in the logics, thus the classical bisimulation quotient can be used for state-space reduction before model checking. },
author = {Chatterjee, Krishnendu and Doyen, Laurent},
location = {Rome, Italy},
publisher = {Schloss Dagstuhl- Leibniz-Zentrum fur Informatik},
title = {{Computation tree logic for synchronization properties}},
doi = {10.4230/LIPIcs.ICALP.2016.98},
volume = {55},
year = {2016},
}
@inproceedings{1071,
abstract = {We consider data-structures for answering reachability and distance queries on constant-treewidth graphs with n nodes, on the standard RAM computational model with wordsize W=Theta(log n). Our first contribution is a data-structure that after O(n) preprocessing time, allows (1) pair reachability queries in O(1) time; and (2) single-source reachability queries in O(n/log n) time. This is (asymptotically) optimal and is faster than DFS/BFS when answering more than a constant number of single-source queries. The data-structure uses at all times O(n) space. Our second contribution is a space-time tradeoff data-structure for distance queries. For any epsilon in [1/2,1], we provide a data-structure with polynomial preprocessing time that allows pair queries in O(n^{1-\epsilon} alpha(n)) time, where alpha is the inverse of the Ackermann function, and at all times uses O(n^epsilon) space. The input graph G is not considered in the space complexity. },
author = {Chatterjee, Krishnendu and Ibsen-Jensen, Rasmus and Pavlogiannis, Andreas},
location = {Aarhus, Denmark},
publisher = {Schloss Dagstuhl- Leibniz-Zentrum fur Informatik},
title = {{Optimal reachability and a space time tradeoff for distance queries in constant treewidth graphs}},
doi = {10.4230/LIPIcs.ESA.2016.28},
volume = {57},
year = {2016},
}
@article{1081,
abstract = {The asymmetric localization of proteins in the plasma membrane domains of eukaryotic cells is a fundamental manifestation of cell polarity that is central to multicellular organization and developmental patterning. In plants, the mechanisms underlying the polar localization of cargo proteins are still largely unknown and appear to be fundamentally distinct from those operating in mammals. Here, we present a systematic, quantitative comparative analysis of the polar delivery and subcellular localization of proteins that characterize distinct polar plasma membrane domains in plant cells. The combination of microscopic analyses and computational modeling revealed a mechanistic framework common to diverse polar cargos and underlying the establishment and maintenance of apical, basal, and lateral polar domains in plant cells. This mechanism depends on the polar secretion, constitutive endocytic recycling, and restricted lateral diffusion of cargos within the plasma membrane. Moreover, our observations suggest that polar cargo distribution involves the individual protein potential to form clusters within the plasma membrane and interact with the extracellular matrix. Our observations provide insights into the shared cellular mechanisms of polar cargo delivery and polarity maintenance in plant cells.},
author = {Łangowski, Łukasz and Wabnik, Krzysztof T and Li, Hongjiang and Vanneste, Steffen and Naramoto, Satoshi and Tanaka, Hirokazu and Friml, Jirí},
journal = {Cell Discovery},
publisher = {Nature Publishing Group},
title = {{Cellular mechanisms for cargo delivery and polarity maintenance at different polar domains in plant cells}},
doi = {10.1038/celldisc.2016.18},
volume = {2},
year = {2016},
}