@article{118, abstract = {While the penetration of objects into granular media is well-studied, there is little understanding of how objects settle in gravities, geff, different from that of Earth - a scenario potentially relevant to the geomorphology of planets and asteroids and also to their exploration using man-made devices. By conducting experiments in an accelerating frame, we explore geff ranging from 0.4 g to 1.2 g. Surprisingly, we find that the rest depth is independent of geff and also that the time required for the object to come to rest scales like geff-1/2. With discrete element modeling simulations, we reproduce the experimental results and extend the range of geff to objects as small as asteroids and as large as Jupiter. Our results shed light on the initial stage of sedimentation into dry granular media across a range of celestial bodies and also have implications for the design of man-made, extraterrestrial vehicles and structures. Key Points The settling depth in granular media is independent of gravity The settling time scales like g-1/2 Layering driven by granular sedimentation should be similar.}, author = {Altshuler, Ernesto and Torres, H and González_Pita, A and Sánchez, Colina G and Pérez Penichet, Carlos and Waitukaitis, Scott R and Hidalgo, Rauól}, journal = {Geophysical Research Letters}, number = {9}, pages = {3032 -- 3037}, publisher = {Wiley-Blackwell}, title = {{Settling into dry granular media in different gravities}}, doi = {10.1002/2014GL059229}, volume = {41}, year = {2014}, } @inproceedings{11855, abstract = {The decremental single-source shortest paths (SSSP) problem concerns maintaining the distances between a given source node s to every node in an n-node m-edge graph G undergoing edge deletions. While its static counterpart can be easily solved in near-linear time, this decremental problem is much more challenging even in the undirected unweighted case. In this case, the classic O(mn) total update time of Even and Shiloach (JACM 1981) has been the fastest known algorithm for three decades. With the loss of a (1 + ε)-approximation factor, the running time was recently improved to O(n 2+o(1) ) by Bernstein and Roditty (SODA 2011), and more recently to O(n 1.8+o(1) + m 1+o(1) ) by Henzinger, Krinninger, and Nanongkai (SODA 2014). In this paper, we finally bring the running time of this case down to near-linear: We give a (1 + ε)-approximation algorithm with O(m 1+o(1) ) total update time, thus obtaining near-linear time. Moreover, we obtain O(m 1+o(1) log W) time for the weighted case, where the edge weights are integers from 1 to W. The only prior work on weighted graphs in o(mn log W) time is the O(mn 0.986 log W)-time algorithm by Henzinger, Krinninger, and Nanongkai (STOC 2014) which works for the general weighted directed case. In contrast to the previous results which rely on maintaining a sparse emulator, our algorithm relies on maintaining a so-called sparse (d, ε)-hop set introduced by Cohen (JACM 2000) in the PRAM literature. A (d, ε)-hop set of a graph G = (V, E) is a set E' of weighted edges such that the distance between any pair of nodes in G can be (1 + ε)-approximated by their d-hop distance (given by a path containing at most d edges) on G'=(V, E∪E'). Our algorithm can maintain an (n o(1) , ε)-hop set of near-linear size in near-linear time under edge deletions. It is the first of its kind to the best of our knowledge. To maintain the distances on this hop set, we develop a monotone bounded-hop Even-Shiloach tree. It results from extending and combining the monotone Even-Shiloach tree of Henzinger, Krinninger, and Nanongkai (FOCS 2013) with the bounded-hop SSSP technique of Bernstein (STOC 2013). These two new tools might be of independent interest.}, author = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon}, booktitle = {55th Annual Symposium on Foundations of Computer Science}, issn = {0272-5428}, location = {Philadelphia, PA, United States}, pages = {146--155}, publisher = {Institute of Electrical and Electronics Engineers}, title = {{Decremental single-source shortest paths on undirected graphs in near-linear total update time}}, doi = {10.1109/focs.2014.24}, year = {2014}, } @inproceedings{11870, abstract = {We consider dynamic algorithms for maintaining Single-Source Reachability (SSR) and approximate Single-Source Shortest Paths (SSSP) on n-node m-edge directed graphs under edge deletions (decremental algorithms). The previous fastest algorithm for SSR and SSSP goes back three decades to Even and Shiloach (JACM 1981); it has O(1) query time and O(mn) total update time (i.e., linear amortized update time if all edges are deleted). This algorithm serves as a building block for several other dynamic algorithms. The question whether its total update time can be improved is a major, long standing, open problem. In this paper, we answer this question affirmatively. We obtain a randomized algorithm which, in a simplified form, achieves an Õ(mn0.984) expected total update time for SSR and (1 + ε)-approximate SSSP, where Õ(·) hides poly log n. We also extend our algorithm to achieve roughly the same running time for Strongly Connected Components (SCC), improving the algorithm of Roditty and Zwick (FOCS 2002), and an algorithm that improves the Õ (mn log W)-time algorithm of Bernstein (STOC 2013) for approximating SSSP on weighted directed graphs, where the edge weights are integers from 1 to W. All our algorithms have constant query time in the worst case.}, author = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon}, booktitle = {46th Annual ACM Symposium on Theory of Computing}, isbn = {978-145032710-7}, issn = {0737-8017}, location = {New York, NY, United States}, publisher = {Association for Computing Machinery}, title = {{Sublinear-time decremental algorithms for single-source reachability and shortest paths on directed graphs}}, doi = {10.1145/2591796.2591869}, year = {2014}, } @inproceedings{11875, abstract = {We present the first deterministic data structures for maintaining approximate minimum vertex cover and maximum matching in a fully dynamic graph in time per update. In particular, for minimum vertex cover we provide deterministic data structures for maintaining a (2 + ε) approximation in O(log n/ε2) amortized time per update. For maximum matching, we show how to maintain a (3 + e) approximation in O(m1/3/ε2) amortized time per update, and a (4 + ε) approximation in O(m1/3/ε2) worst-case time per update. Our data structure for fully dynamic minimum vertex cover is essentially near-optimal and settles an open problem by Onak and Rubinfeld [13].}, author = {Bhattacharya, Sayan and Henzinger, Monika H and Italiano, Giuseppe F.}, booktitle = {26th Annual ACM-SIAM Symposium on Discrete Algorithms}, isbn = {978-1-61197-374-7}, location = {San Diego, CA, United States}, pages = {785--804}, publisher = {Society for Industrial and Applied Mathematics}, title = {{Deterministic fully dynamic data structures for vertex cover and matching}}, doi = {10.1137/1.9781611973730.54}, year = {2014}, } @inproceedings{11876, abstract = {We study dynamic (1 + ∊)-approximation algorithms for the single-source shortest paths problem in an unweighted undirected n-node m-edge graph under edge deletions. The fastest algorithm for this problem is an algorithm with O(n2+o(1)) total update time and constant query time by Bernstein and Roditty (SODA 2011). In this paper, we improve the total update time to O(n1.8+o(1) + m1+o(1)) while keeping the query time constant. This running time is essentially tight when m = Ω(n1.8) since we need Ω(m) time even in the static setting. For smaller values of m, the running time of our algorithm is subquadratic, and is the first that breaks through the quadratic time barrier. In obtaining this result, we develop a fast algorithm for what we call center cover data structure. We also make non-trivial extensions to our previous techniques called lazy-update and monotone Even-Shiloach trees (ICALP 2013 and FOCS 2013). As by-products of our new techniques, we obtain two new results for the decremental all-pairs shortest-paths problem. Our first result is the first approximation algorithm whose total update time is faster than Õ(mn) for all values of m. Our second result is a new trade-off between the total update time and the additive approximation guarantee.}, author = {Henzinger, Monika H and Krinninger, Sebastian and Nanongkai, Danupon}, booktitle = {25th Annual ACM-SIAM Symposium on Discrete Algorithms}, isbn = {978-1-61197-338-9}, location = {Portland, OR, United States}, pages = {1053--1072}, publisher = {Society for Industrial and Applied Mathematics}, title = {{A subquadratic-time algorithm for decremental single-source shortest paths}}, doi = {10.1137/1.9781611973402.79}, year = {2014}, } @article{119, abstract = {Observations of flowing granular matter have suggested that same-material tribocharging depends on particle size, typically rendering large grains positive and small ones negative. Models assuming the transfer of trapped electrons can account for this trend, but have not been validated. Tracking individual grains in an electric field, we show quantitatively that charge is transferred based on size between materially identical grains. However, the surface density of trapped electrons, measured independently by thermoluminescence techniques, is orders of magnitude too small to account for the scale of charge transferred. This reveals that trapped electrons are not a necessary ingredient for same-material tribocharging.}, author = {Waitukaitis, Scott R and Lee, Victor and Pierson, James and Forman, Steven and Jaeger, Heinrich}, journal = {APS Physics, Physical Review Letters}, number = {21}, publisher = {American Physical Society}, title = {{Size-dependent same-material tribocharging in insulating grains}}, doi = {10.1103/PhysRevLett.112.218001}, volume = {112}, year = {2014}, } @article{11967, abstract = {An experimentally easy to perform method for the generation of alumina-supported Fe3O4 nanoparticles [(6±1) nm size, 0.67 wt %]and the use of this material in hydrazine-mediated heterogeneously catalyzed reductions of nitroarenes to anilines under batch and continuous-flow conditions is presented. The bench-stable, reusable nano-Fe3O4@Al2O3 catalyst can selectively reduce functionalized nitroarenes at 1 mol % catalyst loading by using a 20 mol % excess of hydrazine hydrate in an elevated temperature regime (150 °C, reaction time 2–6 min in batch). For continuous-flow processing, the catalyst material is packed into dedicated cartridges and used in a commercially available high-temperature/-pressure flow device. In continuous mode, reaction times can be reduced to less than 1 min at 150 °C (30 bar back pressure) in a highly intensified process. The nano-Fe3O4@Al2O3 catalyst demonstrated stable reduction of nitrobenzene (0.5 M in MeOH) for more than 10 h on stream at a productivity of 30 mmol h−1 (0.72 mol per day). Importantly, virtually no leaching of the catalytically active material could be observed by inductively coupled plasma MS monitoring.}, author = {Moghaddam, Mojtaba Mirhosseini and Pieber, Bartholomäus and Glasnov, Toma and Kappe, C. Oliver}, issn = {1864-564X}, journal = {ChemSusChem}, number = {11}, pages = {3122--3131}, publisher = {Wiley}, title = {{Immobilized iron oxide nanoparticles as stable and reusable catalysts for hydrazine-mediated nitro reductions in continuous flow}}, doi = {10.1002/cssc.201402455}, volume = {7}, year = {2014}, } @article{11968, abstract = {Membrane phospholipids typically contain fatty acids (FAs) of 16 and 18 carbon atoms. This particular chain length is evolutionarily highly conserved and presumably provides maximum stability and dynamic properties to biological membranes in response to nutritional or environmental cues. Here, we show that the relative proportion of C16 versus C18 FAs is regulated by the activity of acetyl-CoA carboxylase (Acc1), the first and rate-limiting enzyme of FA de novo synthesis. Acc1 activity is attenuated by AMPK/Snf1-dependent phosphorylation, which is required to maintain an appropriate acyl-chain length distribution. Moreover, we find that the transcriptional repressor Opi1 preferentially binds to C16 over C18 phosphatidic acid (PA) species: thus, C16-chain containing PA sequesters Opi1 more effectively to the ER, enabling AMPK/Snf1 control of PA acyl-chain length to determine the degree of derepression of Opi1 target genes. These findings reveal an unexpected regulatory link between the major energy-sensing kinase, membrane lipid composition, and transcription.}, author = {Hofbauer, Harald F. and Schopf, Florian H. and Schleifer, Hannes and Knittelfelder, Oskar L. and Pieber, Bartholomäus and Rechberger, Gerald N. and Wolinski, Heimo and Gaspar, Maria L. and Kappe, C. Oliver and Stadlmann, Johannes and Mechtler, Karl and Zenz, Alexandra and Lohner, Karl and Tehlivets, Oksana and Henry, Susan A. and Kohlwein, Sepp D.}, issn = {1878-1551}, journal = {Developmental Cell}, number = {6}, pages = {P729--739}, publisher = {Elsevier}, title = {{Regulation of gene expression through a transcriptional repressor that senses acyl-chain length in membrane phospholipids}}, doi = {10.1016/j.devcel.2014.04.025}, volume = {29}, year = {2014}, } @article{11987, abstract = {A method for the direct lithiation of terminal alkynes and heterocycles with subsequent carboxylation in a continuous flow format was developed. This method provides carboxylic acids at ambient conditions within less than five seconds with only little excess of the organometallic base and CO2.}, author = {Pieber, Bartholomäus and Glasnov, Toma and Kappe, C. O.}, issn = {2046-2069}, journal = {RSC Advances}, number = {26}, publisher = {Royal Society of Chemistry}, title = {{Flash carboxylation: Fast lithiation–carboxylation sequence at room temperature in continuous flow}}, doi = {10.1039/c4ra01442a}, volume = {4}, year = {2014}, } @inproceedings{2080, abstract = {Spinning tops and yo-yos have long fascinated cultures around the world with their unexpected, graceful motions that seemingly elude gravity. We present an algorithm to generate designs for spinning objects by optimizing rotational dynamics properties. As input, the user provides a solid 3D model and a desired axis of rotation. Our approach then modifies the mass distribution such that the principal directions of the moment of inertia align with the target rotation frame. We augment the model by creating voids inside its volume, with interior fill represented by an adaptive multi-resolution vox-elization. The discrete voxel fill values are optimized using a continuous, nonlinear formulation. Further, we optimize for rotational stability by maximizing the dominant principal moment. We extend our technique to incorporate deformation and multiple materials for cases where internal voids alone are insufficient. Our method is well-suited for a variety of 3D printed models, ranging from characters to abstract shapes. We demonstrate tops and yo-yos that spin surprisingly stably despite their asymmetric appearance. }, author = {Bac̈her, Moritz and Whiting, Emily and Bernd Bickel and Sorkine-Hornung, Olga}, number = {4}, publisher = {ACM}, title = {{Spin-It: Optimizing moment of inertia for spinnable objects}}, doi = {10.1145/2601097.2601157}, volume = {33}, year = {2014}, } @inproceedings{2081, abstract = {We propose an interactive, optimization-in-the-loop tool for designing inflatable structures. Given a target shape, the user draws a network of seams defining desired segment boundaries in 3D. Our method computes optimally-shaped flat panels for the segments, such that the inflated structure is as close as possible to the target while satisfying the desired seam positions. Our approach is underpinned by physics-based pattern optimization, accurate coarse-scale simulation using tension field theory, and a specialized constraint-optimization method. Our system is fast enough to warrant interactive exploration of different seam layouts, including internal connections, and their effects on the inflated shape. We demonstrate the resulting design process on a varied set of simulation examples, some of which we have fabricated, demonstrating excellent agreement with the design intent.}, author = {Skouras, Mélina and Thomaszewski, Bernhard and Kaufmann, Peter and Garg, Akash and Bickel, Bernd and Grinspun, Eitan and Gross, Markus}, number = {4}, publisher = {ACM}, title = {{Designing inflatable structures}}, doi = {10.1145/2601097.2601166}, volume = {33}, year = {2014}, } @inproceedings{2082, abstract = {NMAC is a mode of operation which turns a fixed input-length keyed hash function f into a variable input-length function. A practical single-key variant of NMAC called HMAC is a very popular and widely deployed message authentication code (MAC). Security proofs and attacks for NMAC can typically be lifted to HMAC. NMAC was introduced by Bellare, Canetti and Krawczyk [Crypto'96], who proved it to be a secure pseudorandom function (PRF), and thus also a MAC, assuming that (1) f is a PRF and (2) the function we get when cascading f is weakly collision-resistant. Unfortunately, HMAC is typically instantiated with cryptographic hash functions like MD5 or SHA-1 for which (2) has been found to be wrong. To restore the provable guarantees for NMAC, Bellare [Crypto'06] showed its security based solely on the assumption that f is a PRF, albeit via a non-uniform reduction. - Our first contribution is a simpler and uniform proof for this fact: If f is an ε-secure PRF (against q queries) and a δ-non-adaptively secure PRF (against q queries), then NMAC f is an (ε+ℓqδ)-secure PRF against q queries of length at most ℓ blocks each. - We then show that this ε+ℓqδ bound is basically tight. For the most interesting case where ℓqδ ≥ ε we prove this by constructing an f for which an attack with advantage ℓqδ exists. This also violates the bound O(ℓε) on the PRF-security of NMAC recently claimed by Koblitz and Menezes. - Finally, we analyze the PRF-security of a modification of NMAC called NI [An and Bellare, Crypto'99] that differs mainly by using a compression function with an additional keying input. This avoids the constant rekeying on multi-block messages in NMAC and allows for a security proof starting by the standard switch from a PRF to a random function, followed by an information-theoretic analysis. We carry out such an analysis, obtaining a tight ℓq2/2 c bound for this step, improving over the trivial bound of ℓ2q2/2c. The proof borrows combinatorial techniques originally developed for proving the security of CBC-MAC [Bellare et al., Crypto'05].}, author = {Gazi, Peter and Pietrzak, Krzysztof Z and Rybar, Michal}, editor = {Garay, Juan and Gennaro, Rosario}, location = {Santa Barbara, USA}, number = {1}, pages = {113 -- 130}, publisher = {Springer}, title = {{The exact PRF-security of NMAC and HMAC}}, doi = {10.1007/978-3-662-44371-2_7}, volume = {8616}, year = {2014}, } @article{2083, abstract = {Understanding the effects of sex and migration on adaptation to novel environments remains a key problem in evolutionary biology. Using a single-cell alga Chlamydomonas reinhardtii, we investigated how sex and migration affected rates of evolutionary rescue in a sink environment, and subsequent changes in fitness following evolutionary rescue. We show that sex and migration affect both the rate of evolutionary rescue and subsequent adaptation. However, their combined effects change as the populations adapt to a sink habitat. Both sex and migration independently increased rates of evolutionary rescue, but the effect of sex on subsequent fitness improvements, following initial rescue, changed with migration, as sex was beneficial in the absence of migration but constraining adaptation when combined with migration. These results suggest that sex and migration are beneficial during the initial stages of adaptation, but can become detrimental as the population adapts to its environment.}, author = {Lagator, Mato and Morgan, Andrew and Neve, Paul and Colegrave, Nick}, journal = {Evolution}, number = {8}, pages = {2296 -- 2305}, publisher = {Wiley}, title = {{Role of sex and migration in adaptation to sink environments}}, doi = {10.1111/evo.12440}, volume = {68}, year = {2014}, } @article{2084, abstract = {Receptor tyrosine kinases (RTKs) are a large family of cell surface receptors that sense growth factors and hormones and regulate a variety of cell behaviours in health and disease. Contactless activation of RTKs with spatial and temporal precision is currently not feasible. Here, we generated RTKs that are insensitive to endogenous ligands but can be selectively activated by low-intensity blue light. We screened light-oxygen-voltage (LOV)-sensing domains for their ability to activate RTKs by light-activated dimerization. Incorporation of LOV domains found in aureochrome photoreceptors of stramenopiles resulted in robust activation of the fibroblast growth factor receptor 1 (FGFR1), epidermal growth factor receptor (EGFR) and rearranged during transfection (RET). In human cancer and endothelial cells, light induced cellular signalling with spatial and temporal precision. Furthermore, light faithfully mimicked complex mitogenic and morphogenic cell behaviour induced by growth factors. RTKs under optical control (Opto-RTKs) provide a powerful optogenetic approach to actuate cellular signals and manipulate cell behaviour.}, author = {Grusch, Michael and Schelch, Karin and Riedler, Robert and Gschaider-Reichhart, Eva and Differ, Christopher and Berger, Walter and Inglés Prieto, Álvaro and Janovjak, Harald L}, journal = {EMBO Journal}, number = {15}, pages = {1713 -- 1726}, publisher = {Wiley-Blackwell}, title = {{Spatio-temporally precise activation of engineered receptor tyrosine kinases by light}}, doi = {10.15252/embj.201387695}, volume = {33}, year = {2014}, } @article{2086, abstract = {Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed.}, author = {Wolf, Stephan and Mcmahon, Dino and Lim, Ka and Pull, Christopher and Clark, Suzanne and Paxton, Robert and Osborne, Juliet}, journal = {PLoS One}, number = {8}, publisher = {Public Library of Science}, title = {{So near and yet so far: Harmonic radar reveals reduced homing ability of Nosema infected honeybees}}, doi = {10.1371/journal.pone.0103989}, volume = {9}, year = {2014}, } @article{2115, abstract = {The facial performance of an individual is inherently rich in subtle deformation and timing details. Although these subtleties make the performance realistic and compelling, they often elude both motion capture and hand animation. We present a technique for adding fine-scale details and expressiveness to low-resolution art-directed facial performances, such as those created manually using a rig, via marker-based capture, by fitting a morphable model to a video, or through Kinect reconstruction using recent faceshift technology. We employ a high-resolution facial performance capture system to acquire a representative performance of an individual in which he or she explores the full range of facial expressiveness. From the captured data, our system extracts an expressiveness model that encodes subtle spatial and temporal deformation details specific to that particular individual. Once this model has been built, these details can be transferred to low-resolution art-directed performances. We demonstrate results on various forms of input; after our enhancement, the resulting animations exhibit the same nuances and fine spatial details as the captured performance, with optional temporal enhancement to match the dynamics of the actor. Finally, we show that our technique outperforms the current state-of-the-art in example-based facial animation.}, author = {Bermano, Amit H and Bradley, Derek J and Beeler, Thabo and Zund, Fabio and Nowrouzezahrai, Derek and Baran, Ilya and Sorkine-Hornung, Olga and Pfister, Hanspeter and Sumner, Robert W and Bernd Bickel and Groß, Markus S}, journal = {ACM Transactions on Graphics}, number = {2}, publisher = {ACM}, title = {{Facial performance enhancement using dynamic shape space analysis}}, doi = {10.1145/2546276}, volume = {33}, year = {2014}, } @article{2131, abstract = {We study approximations to a class of vector-valued equations of Burgers type driven by a multiplicative space-time white noise. A solution theory for this class of equations has been developed recently in Probability Theory Related Fields by Hairer and Weber. The key idea was to use the theory of controlled rough paths to give definitions of weak/mild solutions and to set up a Picard iteration argument. In this article the limiting behavior of a rather large class of (spatial) approximations to these equations is studied. These approximations are shown to converge and convergence rates are given, but the limit may depend on the particular choice of approximation. This effect is a spatial analogue to the Itô-Stratonovich correction in the theory of stochastic ordinary differential equations, where it is well known that different approximation schemes may converge to different solutions.}, author = {Hairer, Martin M and Jan Maas and Weber, Hendrik}, journal = {Communications on Pure and Applied Mathematics}, number = {5}, pages = {776 -- 870}, publisher = {Wiley-Blackwell}, title = {{Approximating Rough Stochastic PDEs}}, doi = {10.1002/cpa.21495}, volume = {67}, year = {2014}, } @article{2132, abstract = {We consider discrete porous medium equations of the form ∂tρt=Δϕ(ρt), where Δ is the generator of a reversible continuous time Markov chain on a finite set χ, and ϕ is an increasing function. We show that these equations arise as gradient flows of certain entropy functionals with respect to suitable non-local transportation metrics. This may be seen as a discrete analogue of the Wasserstein gradient flow structure for porous medium equations in ℝn discovered by Otto. We present a one-dimensional counterexample to geodesic convexity and discuss Gromov-Hausdorff convergence to the Wasserstein metric.}, author = {Erbar, Matthias and Jan Maas}, journal = {Discrete and Continuous Dynamical Systems- Series A}, number = {4}, pages = {1355 -- 1374}, publisher = {Southwest Missouri State University}, title = {{Gradient flow structures for discrete porous medium equations}}, doi = {10.3934/dcds.2014.34.1355 }, volume = {34}, year = {2014}, } @article{2133, abstract = {Let ℭ denote the Clifford algebra over ℝ𝑛, which is the von Neumann algebra generated by n self-adjoint operators Q j , j = 1,…,n satisfying the canonical anticommutation relations, Q i Q j + Q j Q i = 2δ ij I, and let τ denote the normalized trace on ℭ. This algebra arises in quantum mechanics as the algebra of observables generated by n fermionic degrees of freedom. Let 𝔓 denote the set of all positive operators 𝜌∈ℭ such that τ(ρ) = 1; these are the non-commutative analogs of probability densities in the non-commutative probability space (ℭ,𝜏). The fermionic Fokker–Planck equation is a quantum-mechanical analog of the classical Fokker–Planck equation with which it has much in common, such as the same optimal hypercontractivity properties. In this paper we construct a Riemannian metric on 𝔓 that we show to be a natural analog of the classical 2-Wasserstein metric, and we show that, in analogy with the classical case, the fermionic Fokker–Planck equation is gradient flow in this metric for the relative entropy with respect to the ground state. We derive a number of consequences of this, such as a sharp Talagrand inequality for this metric, and we prove a number of results pertaining to this metric. Several open problems are raised.}, author = {Carlen, Eric and Maas, Jan}, journal = {Communications in Mathematical Physics}, number = {3}, pages = {887 -- 926}, publisher = {Springer}, title = {{An analog of the 2-Wasserstein metric in non-commutative probability under which the fermionic Fokker-Planck equation is gradient flow for the entropy}}, doi = {10.1007/s00220-014-2124-8}, volume = {331}, year = {2014}, } @article{2140, abstract = {We propose a technique for engineering momentum-dependent dissipation in Bose-Einstein condensates with non-local interactions. The scheme relies on the use of momentum-dependent dark-states in close analogy to velocity-selective coherent population trapping. During the short-time dissipative dynamics, the system is driven into a particular finite-momentum phonon mode, which in real space corresponds to an ordered structure with non-local density-density correlations. Dissipation-induced ordering can be observed and studied in present-day experiments using cold atoms with dipole-dipole or off-resonant Rydberg interactions. Due to its dissipative nature, the ordering does not require artificial breaking of translational symmetry by an opticallattice or harmonic trap. This opens up a perspective of direct cooling of quantum gases into strongly-interacting phases.}, author = {Otterbach, Johannes and Lemeshko, Mikhail}, journal = {Physical Review Letters}, number = {7}, publisher = {American Physical Society}, title = {{Dissipative preparation of spatial order in Rydberg-dressed Bose-Einstein condensates}}, doi = {10.1103/PhysRevLett.113.070401}, volume = {113}, year = {2014}, }