Institution
University of California, Santa Barbara
Education•Santa Barbara, California, United States•
About: University of California, Santa Barbara is a education organization based out in Santa Barbara, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 30281 authors who have published 80852 publications receiving 4626827 citations. The organization is also known as: UC Santa Barbara & UCSB.
Topics: Population, Galaxy, Laser, Quantum well, Quantum dot
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors present cosmological parameter results from the full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstruction.
Abstract: We present cosmological parameter results from the final full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstruction Compared to the 2015 results, improved measurements of large-scale polarization allow the reionization optical depth to be measured with higher precision, leading to significant gains in the precision of other correlated parameters Improved modelling of the small-scale polarization leads to more robust constraints on manyparameters,withresidualmodellinguncertaintiesestimatedtoaffectthemonlyatthe05σlevelWefindgoodconsistencywiththestandard spatially-flat6-parameter ΛCDMcosmologyhavingapower-lawspectrumofadiabaticscalarperturbations(denoted“base ΛCDM”inthispaper), from polarization, temperature, and lensing, separately and in combination A combined analysis gives dark matter density Ωch2 = 0120±0001, baryon density Ωbh2 = 00224±00001, scalar spectral index ns = 0965±0004, and optical depth τ = 0054±0007 (in this abstract we quote 68% confidence regions on measured parameters and 95% on upper limits) The angular acoustic scale is measured to 003% precision, with 100θ∗ = 10411±00003Theseresultsareonlyweaklydependentonthecosmologicalmodelandremainstable,withsomewhatincreasederrors, in many commonly considered extensions Assuming the base-ΛCDM cosmology, the inferred (model-dependent) late-Universe parameters are: HubbleconstantH0 = (674±05)kms−1Mpc−1;matterdensityparameterΩm = 0315±0007;andmatterfluctuationamplitudeσ8 = 0811±0006 We find no compelling evidence for extensions to the base-ΛCDM model Combining with baryon acoustic oscillation (BAO) measurements (and consideringsingle-parameterextensions)weconstraintheeffectiveextrarelativisticdegreesoffreedomtobe Neff = 299±017,inagreementwith the Standard Model prediction Neff = 3046, and find that the neutrino mass is tightly constrained toPmν < 012 eV The CMB spectra continue to prefer higher lensing amplitudesthan predicted in base ΛCDM at over 2σ, which pulls some parameters that affect thelensing amplitude away from the ΛCDM model; however, this is not supported by the lensing reconstruction or (in models that also change the background geometry) BAOdataThejointconstraintwithBAOmeasurementsonspatialcurvatureisconsistentwithaflatuniverse, ΩK = 0001±0002Alsocombining with Type Ia supernovae (SNe), the dark-energy equation of state parameter is measured to be w0 = −103±003, consistent with a cosmological constant We find no evidence for deviations from a purely power-law primordial spectrum, and combining with data from BAO, BICEP2, and Keck Array data, we place a limit on the tensor-to-scalar ratio r0002 < 006 Standard big-bang nucleosynthesis predictions for the helium and deuterium abundances for the base-ΛCDM cosmology are in excellent agreement with observations The Planck base-ΛCDM results are in good agreement with BAO, SNe, and some galaxy lensing observations, but in slight tension with the Dark Energy Survey’s combined-probe results including galaxy clustering (which prefers lower fluctuation amplitudes or matter density parameters), and in significant, 36σ, tension with local measurements of the Hubble constant (which prefer a higher value) Simple model extensions that can partially resolve these tensions are not favoured by the Planck data
4,688 citations
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TL;DR: By applying specific fabrication conditions summarized in the Experimental section and post-production annealing at 150°C, polymer solar cells with power-conversion efficiency approaching 5% were demonstrated.
Abstract: By applying the specific fabrication conditions summarized in the Experimental section and post-production annealing at 150 °C, polymer solar cells with power-conversion efficiency approaching 5 % are demonstrated. These devices exhibit remarkable thermal stability. We attribute the improved performance to changes in the bulk heterojunction material induced by thermal annealing. The improved nanoscale morphology, the increased crystallinity of the semiconducting polymer, and the improved contact to the electron-collecting electrode facilitate charge generation, charge transport to, and charge collection at the electrodes, thereby enhancing the device efficiency by lowering the series resistance of the polymer solar cells.
4,513 citations
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Tohoku University1, University of Zurich2, Lawrence Berkeley National Laboratory3, Stanford University4, College of William & Mary5, University of Genoa6, University of Urbino7, CERN8, Budker Institute of Nuclear Physics9, University of California, Irvine10, Cornell University11, Argonne National Laboratory12, ETH Zurich13, Tata Institute of Fundamental Research14, Hillsdale College15, Spanish National Research Council16, Ohio State University17, University of Notre Dame18, Kent State University19, University of California, San Diego20, University of California, Berkeley21, University of Minnesota22, University of Alabama23, University of Helsinki24, Los Alamos National Laboratory25, California Institute of Technology26, George Washington University27, Syracuse University28, Lawrence Livermore National Laboratory29, Oklahoma State University–Stillwater30, University of Washington31, Max Planck Society32, Boston University33, University of California, Los Angeles34, Royal Holloway, University of London35, Université Paris-Saclay36, Fermilab37, University of Pennsylvania38, University of Illinois at Urbana–Champaign39, University of Bristol40, University of Tokyo41, University of Delaware42, Carnegie Mellon University43, University of California, Santa Cruz44, Karlsruhe Institute of Technology45, Heidelberg University46, Florida State University47, Carleton University48, University of Mainz49, University of Edinburgh50, Brookhaven National Laboratory51, Durham University52, University of Lausanne53, Massachusetts Institute of Technology54, University of Southampton55, Nagoya University56, University of Oxford57, Northwestern University58, University of British Columbia59, Columbia University60, Lund University61, University of Sheffield62, University of California, Santa Barbara63, Iowa State University64, University of Alberta65, University of Cambridge66
TL;DR: The Particle Data Group's biennial review as mentioned in this paper summarizes much of particle physics, using data from previous editions, plus 2658 new measurements from 644 papers, and lists, evaluates, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons.
Abstract: This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, V-cb & V-ub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.
4,465 citations
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TL;DR: In this article, the authors describe the mathematical underpinnings of topological quantum computation and the physics of the subject are addressed, using the ''ensuremath{
u}=5∕2$ fractional quantum Hall state as the archetype of a non-Abelian topological state enabling fault-tolerant quantum computation.
Abstract: Topological quantum computation has emerged as one of the most exciting approaches to constructing a fault-tolerant quantum computer. The proposal relies on the existence of topological states of matter whose quasiparticle excitations are neither bosons nor fermions, but are particles known as non-Abelian anyons, meaning that they obey non-Abelian braiding statistics. Quantum information is stored in states with multiple quasiparticles, which have a topological degeneracy. The unitary gate operations that are necessary for quantum computation are carried out by braiding quasiparticles and then measuring the multiquasiparticle states. The fault tolerance of a topological quantum computer arises from the nonlocal encoding of the quasiparticle states, which makes them immune to errors caused by local perturbations. To date, the only such topological states thought to have been found in nature are fractional quantum Hall states, most prominently the $\ensuremath{
u}=5∕2$ state, although several other prospective candidates have been proposed in systems as disparate as ultracold atoms in optical lattices and thin-film superconductors. In this review article, current research in this field is described, focusing on the general theoretical concepts of non-Abelian statistics as it relates to topological quantum computation, on understanding non-Abelian quantum Hall states, on proposed experiments to detect non-Abelian anyons, and on proposed architectures for a topological quantum computer. Both the mathematical underpinnings of topological quantum computation and the physics of the subject are addressed, using the $\ensuremath{
u}=5∕2$ fractional quantum Hall state as the archetype of a non-Abelian topological state enabling fault-tolerant quantum computation.
4,457 citations
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TL;DR: Routing protocols for ad hoc networks are examined by providing an overview of eight different protocols by presenting their characteristics and functionality, and then a comparison and discussion of their respective merits and drawbacks are provided.
Abstract: An ad hoc mobile network is a collection of mobile nodes that are dynamically and arbitrarily located in such a manner that the interconnections between nodes are capable of changing on a continual basis. In order to facilitate communication within the network, a routing protocol is used to discover routes between nodes. The primary goal of such an ad hoc network routing protocol is correct and efficient route establishment between a pair of nodes so that messages may be delivered in a timely manner. Route construction should be done with a minimum of overhead and bandwidth consumption. This article examines routing protocols for ad hoc networks and evaluates these protocols based on a given set of parameters. The article provides an overview of eight different protocols by presenting their characteristics and functionality, and then provides a comparison and discussion of their respective merits and drawbacks.
4,278 citations
Authors
Showing all 30652 results
Name | H-index | Papers | Citations |
---|---|---|---|
George M. Whitesides | 240 | 1739 | 269833 |
Yi Chen | 217 | 4342 | 293080 |
Simon D. M. White | 189 | 795 | 231645 |
George Efstathiou | 187 | 637 | 156228 |
Peidong Yang | 183 | 562 | 144351 |
David R. Williams | 178 | 2034 | 138789 |
Alan J. Heeger | 171 | 913 | 147492 |
Richard H. Friend | 169 | 1182 | 140032 |
Jiawei Han | 168 | 1233 | 143427 |
Gang Chen | 167 | 3372 | 149819 |
Alexander S. Szalay | 166 | 936 | 145745 |
Omar M. Yaghi | 165 | 459 | 163918 |
Carlos S. Frenk | 165 | 799 | 140345 |
Yang Yang | 164 | 2704 | 144071 |
Carlos Bustamante | 161 | 770 | 106053 |