@article{1013, abstract = {From microwave ovens to satellite television to the GPS and data services on our mobile phones, microwave technology is everywhere today. But one technology that has so far failed to prove its worth in this wavelength regime is quantum communication that uses the states of single photons as information carriers. This is because single microwave photons, as opposed to classical microwave signals, are extremely vulnerable to noise from thermal excitations in the channels through which they travel. Two new independent studies, one by Ze-Liang Xiang at Technische Universität Wien (Vienna), Austria, and colleagues [1] and another by Benoît Vermersch at the University of Innsbruck, also in Austria, and colleagues [2] now describe a theoretical protocol for microwave quantum communication that is resilient to thermal and other types of noise. Their approach could become a powerful technique to establish fast links between superconducting data processors in a future all-microwave quantum network.}, author = {Fink, Johannes M}, journal = {Physics}, number = {32}, publisher = {American Physical Society}, title = {{Viewpoint: Microwave quantum states beat the heat}}, doi = {10.1103/Physics.10.32}, volume = {10}, year = {2017}, } @article{10126, author = {Vahid Belarghou, Afshin and Šarić, Anđela and Idema, Timon}, issn = {0006-3495}, journal = {Biophysical Journal}, keywords = {biophysics}, number = {3}, publisher = {Elsevier }, title = {{Curvature mediated interactions in highly curved membranes}}, doi = {10.1016/j.bpj.2016.11.2123}, volume = {112}, year = {2017}, } @article{10175, abstract = {We study periodic homogenization by Γ-convergence of integral functionals with integrands W(x,ξ) having no polynomial growth and which are both not necessarily continuous with respect to the space variable and not necessarily convex with respect to the matrix variable. This allows to deal with homogenization of composite hyperelastic materials consisting of two or more periodic components whose the energy densities tend to infinity as the volume of matter tends to zero, i.e., W(x,ξ)=∑j∈J1Vj(x)Hj(ξ) where {Vj}j∈J is a finite family of open disjoint subsets of RN, with |∂Vj|=0 for all j∈J and ∣∣RN∖⋃j∈JVj|=0, and, for each j∈J, Hj(ξ)→∞ as detξ→0. In fact, our results apply to integrands of type W(x,ξ)=a(x)H(ξ) when H(ξ)→∞ as detξ→0 and a∈L∞(RN;[0,∞[) is 1-periodic and is either continuous almost everywhere or not continuous. When a is not continuous, we obtain a density homogenization formula which is a priori different from the classical one by Braides–Müller. Although applications to hyperelasticity are limited due to the fact that our framework is not consistent with the constraint of noninterpenetration of the matter, our results can be of technical interest to analysis of homogenization of integral functionals.}, author = {Anza Hafsa, Omar and Clozeau, Nicolas and Mandallena, Jean-Philippe}, issn = {2118-7436}, journal = {Annales mathématiques Blaise Pascal}, number = {2}, pages = {135--193}, publisher = {Université Clermont Auvergne}, title = {{Homogenization of nonconvex unbounded singular integrals}}, doi = {10.5802/ambp.367}, volume = {24}, year = {2017}, } @article{103, abstract = {We investigate effects of quasiparticle poisoning in a Majorana island with strong tunnel coupling to normal-metal leads. In addition to the main Coulomb blockade diamonds, "shadow" diamonds appear, shifted by 1e in gate voltage, consistent with transport through an excited (poisoned) state of the island. Comparison to a simple model yields an estimate of parity lifetime for the strongly coupled island (∼1 μs) and sets a bound for a weakly coupled island (>10 μs). Fluctuations in the gate-voltage spacing of Coulomb peaks at high field, reflecting Majorana hybridization, are enhanced by the reduced lever arm at strong coupling. When converted from gate voltage to energy units, fluctuations are consistent with previous measurements.}, author = {Albrecht, S M and Hansen, Esben and Higginbotham, Andrew P and Kuemmeth, Ferdinand and Jespersen, Thomas and Nygård, Jesper and Krogstrup, Peter and Danon, Jeroen and Flensberg, Karsten and Marcus, Charles}, journal = {APS Physics, Physical Review Letters}, number = {13}, publisher = {American Physical Society}, title = {{Transport signatures of quasiparticle poisoning in a majorana island}}, doi = {10.1103/PhysRevLett.118.137701}, volume = {118}, year = {2017}, } @article{10370, abstract = {Eukaryotic cells are densely packed with macromolecular complexes and intertwining organelles, continually transported and reshaped. Intriguingly, organelles avoid clashing and entangling with each other in such limited space. Mitochondria form extensive networks constantly remodeled by fission and fusion. Here, we show that mitochondrial fission is triggered by mechanical forces. Mechano-stimulation of mitochondria – via encounter with motile intracellular pathogens, via external pressure applied by an atomic force microscope, or via cell migration across uneven microsurfaces – results in the recruitment of the mitochondrial fission machinery, and subsequent division. We propose that MFF, owing to affinity for narrow mitochondria, acts as a membrane-bound force sensor to recruit the fission machinery to mechanically strained sites. Thus, mitochondria adapt to the environment by sensing and responding to biomechanical cues. Our findings that mechanical triggers can be coupled to biochemical responses in membrane dynamics may explain how organelles orderly cohabit in the crowded cytoplasm.}, author = {Helle, Sebastian Carsten Johannes and Feng, Qian and Aebersold, Mathias J and Hirt, Luca and Grüter, Raphael R and Vahid, Afshin and Sirianni, Andrea and Mostowy, Serge and Snedeker, Jess G and Šarić, Anđela and Idema, Timon and Zambelli, Tomaso and Kornmann, Benoît}, issn = {2050-084X}, journal = {eLife}, keywords = {general immunology and microbiology, general biochemistry, genetics and molecular biology, general medicine, general neuroscience}, publisher = {eLife Sciences Publications}, title = {{Mechanical force induces mitochondrial fission}}, doi = {10.7554/elife.30292}, volume = {6}, year = {2017}, } @article{10369, abstract = {Biological membranes have a central role in mediating the organization of membrane-curving proteins, a dynamic process that has proven to be challenging to probe experimentally. Using atomic force microscopy, we capture the hierarchically organized assemblies of Bin/amphiphysin/Rvs (BAR) proteins on supported lipid membranes. Their structure reveals distinct long linear aggregates of proteins, regularly spaced by up to 300 nm. Employing accurate free-energy calculations from large-scale coarse-grained computer simulations, we found that the membrane mediates the interaction among protein filaments as a combination of short- and long-ranged interactions. The long-ranged component acts at strikingly long distances, giving rise to a variety of micron-sized ordered patterns. This mechanism may contribute to the long-ranged spatiotemporal control of membrane remodeling by proteins in the cell.}, author = {Simunovic, Mijo and Šarić, Anđela and Henderson, J. Michael and Lee, Ka Yee C. and Voth, Gregory A.}, issn = {2374-7951}, journal = {ACS Central Science}, keywords = {general chemical engineering, general chemistry}, number = {12}, pages = {1246--1253}, publisher = {American Chemical Society}, title = {{Long-range organization of membrane-curving proteins}}, doi = {10.1021/acscentsci.7b00392}, volume = {3}, year = {2017}, } @article{10373, abstract = {Electric charges are conserved. The same would be expected to hold for magnetic charges, yet magnetic monopoles have never been observed. It is therefore surprising that the laws of nonequilibrium thermodynamics, combined with Maxwell’s equations, suggest that colloidal particles heated or cooled in certain polar or paramagnetic solvents may behave as if they carry an electric/magnetic charge. Here, we present numerical simulations that show that the field distribution around a pair of such heated/cooled colloidal particles agrees quantitatively with the theoretical predictions for a pair of oppositely charged electric or magnetic monopoles. However, in other respects, the nonequilibrium colloidal particles do not behave as monopoles: They cannot be moved by a homogeneous applied field. The numerical evidence for the monopole-like fields around heated/cooled colloidal particles is crucial because the experimental and numerical determination of forces between such colloidal particles would be complicated by the presence of other effects, such as thermophoresis.}, author = {Wirnsberger, Peter and Fijan, Domagoj and Lightwood, Roger A. and Šarić, Anđela and Dellago, Christoph and Frenkel, Daan}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, keywords = {multidisciplinary}, number = {19}, pages = {4911--4914}, publisher = {National Academy of Sciences}, title = {{Numerical evidence for thermally induced monopoles}}, doi = {10.1073/pnas.1621494114}, volume = {114}, year = {2017}, } @article{10374, abstract = {The formation of filaments from naturally occurring protein molecules is a process at the core of a range of functional and aberrant biological phenomena, such as the assembly of the cytoskeleton or the appearance of aggregates in Alzheimer's disease. The macroscopic behaviour associated with such processes is remarkably diverse, ranging from simple nucleated growth to highly cooperative processes with a well-defined lagtime. Thus, conventionally, different molecular mechanisms have been used to explain the self-assembly of different proteins. Here we show that this range of behaviour can be quantitatively captured by a single unifying Petri net that describes filamentous growth in terms of aggregate number and aggregate mass concentrations. By considering general features associated with a particular network connectivity, we are able to establish directly the rate-determining steps of the overall aggregation reaction from the system's scaling behaviour. We illustrate the power of this framework on a range of different experimental and simulated aggregating systems. The approach is general and will be applicable to any future extensions of the reaction network of filamentous self-assembly.}, author = {Meisl, Georg and Rajah, Luke and Cohen, Samuel A. I. and Pfammatter, Manuela and Šarić, Anđela and Hellstrand, Erik and Buell, Alexander K. and Aguzzi, Adriano and Linse, Sara and Vendruscolo, Michele and Dobson, Christopher M. and Knowles, Tuomas P. J.}, issn = {2041-6539}, journal = {Chemical Science}, keywords = {general chemistry}, number = {10}, pages = {7087--7097}, publisher = {Royal Society of Chemistry}, title = {{Scaling behaviour and rate-determining steps in filamentous self-assembly}}, doi = {10.1039/c7sc01965c}, volume = {8}, year = {2017}, } @article{10375, abstract = {Cellular membranes exhibit a large variety of shapes, strongly coupled to their function. Many biological processes involve dynamic reshaping of membranes, usually mediated by proteins. This interaction works both ways: while proteins influence the membrane shape, the membrane shape affects the interactions between the proteins. To study these membrane-mediated interactions on closed and anisotropically curved membranes, we use colloids adhered to ellipsoidal membrane vesicles as a model system. We find that two particles on a closed system always attract each other, and tend to align with the direction of largest curvature. Multiple particles form arcs, or, at large enough numbers, a complete ring surrounding the vesicle in its equatorial plane. The resulting vesicle shape resembles a snowman. Our results indicate that these physical interactions on membranes with anisotropic shapes can be exploited by cells to drive macromolecules to preferred regions of cellular or intracellular membranes, and utilized to initiate dynamic processes such as cell division. The same principle could be used to find the midplane of an artificial vesicle, as a first step towards dividing it into two equal parts.}, author = {Vahid, Afshin and Šarić, Anđela and Idema, Timon}, issn = {1744-6848}, journal = {Soft Matter}, keywords = {condensed matter physics, general chemistry}, number = {28}, pages = {4924--4930}, publisher = {Royal Society of Chemistry}, title = {{Curvature variation controls particle aggregation on fluid vesicles}}, doi = {10.1039/c7sm00433h}, volume = {13}, year = {2017}, } @article{10418, abstract = {We present a new proof rule for proving almost-sure termination of probabilistic programs, including those that contain demonic non-determinism. An important question for a probabilistic program is whether the probability mass of all its diverging runs is zero, that is that it terminates "almost surely". Proving that can be hard, and this paper presents a new method for doing so. It applies directly to the program's source code, even if the program contains demonic choice. Like others, we use variant functions (a.k.a. "super-martingales") that are real-valued and decrease randomly on each loop iteration; but our key innovation is that the amount as well as the probability of the decrease are parametric. We prove the soundness of the new rule, indicate where its applicability goes beyond existing rules, and explain its connection to classical results on denumerable (non-demonic) Markov chains.}, author = {Mciver, Annabelle and Morgan, Carroll and Kaminski, Benjamin Lucien and Katoen, Joost P}, issn = {2475-1421}, journal = {Proceedings of the ACM on Programming Languages}, location = {Los Angeles, CA, United States}, number = {POPL}, publisher = {Association for Computing Machinery}, title = {{A new proof rule for almost-sure termination}}, doi = {10.1145/3158121}, volume = {2}, year = {2017}, }