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Evidence for Gravitational Lensing of the Cosmic Microwave Background Polarization from Cross-Correlation with the Cosmic Infrared Background

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Physical Review Letters 2014年第13期112卷 131302-131302页

作者： P. A. R. Ade Y. Akiba A. E. Anthony K. Arnold M. Atlas D. Barron D. Boettger J. Borrill C. Borys S. Chapman Y. Chinone M. Dobbs T. Elleflot J. Errard G. Fabbian C. Feng D. Flanigan A. Gilbert W. Grainger N. W. Halverson M. Hasegawa K. Hattori M. Hazumi W. L. Holzapfel Y. Hori J. Howard P. Hyland Y. Inoue G. C. Jaehnig A. Jaffe B. Keating Z. Kermish R. Keskitalo T. Kisner M. Le Jeune A. T. Lee E. M. Leitch E. Linder M. Lungu F. Matsuda T. Matsumura X. Meng N. J. Miller H. Morii S. Moyerman M. J. Myers M. Navaroli H. Nishino H. Paar J. Peloton D. Poletti E. Quealy G. Rebeiz C. L. Reichardt P. L. Richards C. Ross K. Rotermund I. Schanning D. E. Schenck B. D. Sherwin A. Shimizu C. Shimmin M. Shimon P. Siritanasak G. Smecher H. Spieler N. Stebor B. Steinbach R. Stompor A. Suzuki S. Takakura A. Tikhomirov T. Tomaru B. Wilson A. Yadav O. Zahn School of Physics and Astronomy Cardiff University Cardiff CF10 3XQ United Kingdom The Graduate University for Advanced Studies Hayama Miura District Kanagawa 240-0115 Japan Center for Astrophysics and Space Astronomy University of Colorado Boulder CO 80309 USA Department of Astrophysical and Planetary Sciences University of Colorado Boulder CO 80309 USA Department of Physics University of California San Diego CA 92093-0424 USA Computational Cosmology Center Lawrence Berkeley National Laboratory Berkeley CA 92093-0424 USA Space Sciences Laboratory University of California Berkeley CA 94720 USA California Institute of Technology Pasadena California USA Department of Physics and Atmospheric Science Dalhousie University Halifax NS B3H 4R2 Canada High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan Department of Physics University of California Berkeley CA 94720 USA Physics Department McGill University Montreal QC H3A 0G4 Canada AstroParticule et Cosmologie Univ Paris Diderot CNRS/IN2P3 CEA/Irfu Obs de Paris Sorbonne Paris Cité France International School for Advanced Studies (SISSA) Trieste 34014 Italy Department of Physics Columbia University New York NY 10027 USA Rutherford Appleton Laboratory STFC Swindon SN2 1SZ United Kingdom Department of Physics University of Colorado Boulder CO 80309 USA Kavli Institute for the Physics and Mathematics of the Universe (WPI) Todai Institutes for Advanced Study The University of Tokyo Kashiwa Chiba 277-8583 Japan Department of Physics University of Oxford Oxford OX1 2JD United Kingdom Physics Department Austin College Sherman TX 75090 USA Department of Physics Imperial College London London SW7 2AZ United Kingdom Physics Department Princeton University Princeton NJ 08544 USA Physics Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA Department of Astronomy and Astrophysics University of Chicago Chicago IL 60637 USA Kavli Institute for Cosm

We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

关键词： Polarization

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Rotational and translational diffusion of anisotropic gold nanoparticles in liquid crystals controlled by varying surface anchoring

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Physical Review E 2013年第6期88卷 062507-062507页

作者： Bohdan Senyuk David Glugla Ivan I. Smalyukh Department of Physics University of Colorado at Boulder Boulder Colorado 80309 USA Department of Electrical Computer and Energy Engineering University of Colorado at Boulder Boulder Colorado 80309 USA Liquid Crystals Materials Research Center and Materials Science and Engineering Program University of Colorado at Boulder Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado at Boulder Boulder Colorado 80309 USA

We study translational and rotational diffusion of anisotropic gold nanoparticles (NPs) dispersed in the bulk of a nematic liquid crystal fluid host. Experimental data reveal strong anisotropy of translational diffusion with respect to the uniform far-field director, which is dependent on shape and surface functionalization of colloids as well as on their ground-state alignment. For example, elongated NPs aligned parallel to the far-field director translationally diffuse more rapidly along the director whereas diffusion of NPs oriented normal to the director is faster in the direction perpendicular to it while they are also undergoing elasticity-constrained rotational diffusion. To understand physical origins of these rich diffusion properties of anisotropic nanocolloids in uniaxially anisotropic nematic fluid media, we compare them to diffusion of prolate and oblate ellipsoidal particles in isotropic fluids as well as to diffusion of shape-isotropic particles in nematic fluids. We also show that surface functionalization of NPs with photosensitive azobenzene groups allows for in situ control of their diffusivity through trans-cis isomerization that changes surface anchoring.

关键词： Gold nanoparticles

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Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum with the POLARBEAR Experiment

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Physical Review Letters 2014年第2期113卷 021301-021301页

作者： P. A. R. Ade Y. Akiba A. E. Anthony K. Arnold M. Atlas D. Barron D. Boettger J. Borrill S. Chapman Y. Chinone M. Dobbs T. Elleflot J. Errard G. Fabbian C. Feng D. Flanigan A. Gilbert W. Grainger N. W. Halverson M. Hasegawa K. Hattori M. Hazumi W. L. Holzapfel Y. Hori J. Howard P. Hyland Y. Inoue G. C. Jaehnig A. Jaffe B. Keating Z. Kermish R. Keskitalo T. Kisner M. Le Jeune A. T. Lee E. Linder E. M. Leitch M. Lungu F. Matsuda T. Matsumura X. Meng N. J. Miller H. Morii S. Moyerman M. J. Myers M. Navaroli H. Nishino H. Paar J. Peloton E. Quealy G. Rebeiz C. L. Reichardt P. L. Richards C. Ross I. Schanning D. E. Schenck B. Sherwin A. Shimizu C. Shimmin M. Shimon P. Siritanasak G. Smecher H. Spieler N. Stebor B. Steinbach R. Stompor A. Suzuki S. Takakura T. Tomaru B. Wilson A. Yadav O. Zahn School of Physics and Astronomy Cardiff University Cardiff CF10 3XQ United Kingdom The Graduate University for Advanced Studies Hayama Miura District Kanagawa 240-0115 Japan Center for Astrophysics and Space Astronomy University of Colorado Boulder Colorado 80309 USA Department of Physics University of California San Diego La Jolla California 92093-0424 USA Computational Cosmology Center Lawrence Berkeley National Laboratory Berkeley California 92093-0424 USA Space Sciences Laboratory University of California Berkeley Berkeley California 94720 USA Department of Physics and Atmospheric Science Dalhousie University Halifax Nova Scotia B3H 4R2 Canada High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan Department of Physics University of California Berkeley Berkeley California 94720 USA Physics Department McGill University Montreal Quebec H3A 0G4 Canada AstroParticule et Cosmologie Univ Paris Diderot CNRS/IN2P3 CEA/Irfu Obs de Paris Sorbonne Paris Cité France International School for Advanced Studies (SISSA) Trieste 34014 Italy Columbia University New York New York 10027 USA Rutherford Appleton Laboratory STFC Swindon SN2 1SZ United Kingdom Department of Astrophysical and Planetary Sciences University of Colorado Boulder Colorado 80309 USA Department of Physics University of Colorado Boulder Colorado 80309 USA Kavli Institute for the Physics and Mathematics of the Universe (WPI) Todai Institutes for Advanced Study The University of Tokyo Kashiwa Chiba 277-8583 Japan Department of Physics University of Oxford Oxford OX1 2JD United Kingdom Physics Department Austin College Sherman Texas 75090 USA Department of Physics Imperial College London London SW7 2AZ United Kingdom Physics Department Princeton University Princeton New Jersey 08544 USA Physics Division Lawrence Berkeley National Laboratory Berkeley California 92093-0424 USA Department of Astronomy and Astrophysics University of Chicago 5640 South

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

关键词： Polarization

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Exploring pervasive service computing opportunities for pursuing successful ageing

Exploring pervasive service computing opportunities for purs...

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1st Int. Workshop on Self-Managing Solutions for Smart Environments, S3E 2011 and Int. Workshop on Health and Well-Being Tech. and Services for Elderly, HWTS 2011, Held in Conjunction with the 6th Int. Conf on Grid and Pervasive Comp.GPC 2011

作者： Zhou, Jiehan Su, Xiang Ylianttila, Mika Riekki, Jukka Computer Science and Engineering Laboratory and Infotech Oulu University of Oulu 90014 Oulu Finland Middleware Systems Research Group Department of Electrical and Computer Engineering University of Toronto Canada

ISBN: (纸本)9783642279157

Pervasive Service Computing for Elderly applies service composition and pervasive computing into assisting elderly Activities of Daily Life. Taking advantages of context-awareness and service-oriented computing, Pervasive Service Computing expects to bring brilliant opportunities for pursuing global successful ageing. This paper proposes a Pervasive Service Computing for Elderly (PSC4E) framework for improving Quality of Life of elderly people, through providing being-, becoming-, and belonging-based services in context of population ageing trends, an elderly service provisioning model, and related studies. © 2012 Springer-Verlag.

关键词： Ubiquitous computing

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Performance analysis of planar inductor based snubbing circuit on EMI effects generated by switching action in DC/DC Boost converter

Performance analysis of planar inductor based snubbing circu...

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International Symposium on Electromagnetic Compatibility, EMC EUROPE 2012

作者： Nejadpak, Arash Mohammed, Osama A. Energy Systems Research Laboratory Electrical and Computer Engineering Department Florida International University Miami United States

ISBN: (纸本)9781467307185

In this paper, a planar inductor based snubber circuit is presented for power MOSFET devices used in a Boost power converters. The proposed snubber can control the EMI effects caused by the switching actions which can affect the drive circuit. Appropriate use of the snubber and considering the parasitic elements in the switching circuits can improve the conducted EMI of the converter, eliminating the need for the bulky EMI filters. To design an effective snubber circuit, a physics based model of the switch and the snubber circuit components are considered. Using impedance control method, the effects of various parasitic elements that can cause the common-mode noise can be controlled. This effort enables the evaluation of interference issues for EMC evaluation studies early in the design process. The numerical results were validated experimentally. © 2012 IEEE.

关键词： Electromagnetic compatibility

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Femtosecond laser frequency comb for astrophysical spectrograph calibration

Femtosecond laser frequency comb for astrophysical spectrogr...

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Advanced Solid State Lasers, ASSL 2013

作者： Chang, Guoqing Li, Chih-Hao Glenday, Alexander Furesz, Gabor Langellier, Nicholas Chen, Li-Jin Lim, Jinkang Chen, Hung-Wen Phillips, David F. Sasselov, Dimitar Szentgyorgyi, Andrew Walsworth, Ronald L. Kärtner, Franz X. Center for Free-Electron Laser Science DESY Notkestraße 85 22607 Hamburg Germany Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 United States Harvard-Smithsonian Center for Astrophysics Harvard University 60 Garden St Cambridge MA 02138 United States Idesta Quantum Electronics INC 435 Route 206N Newton NJ 07860 United States Department of Physics Harvard University 60 Garden Street Cambridge MA 02138 United States Physics Department University of Hamburg Luruper Chaussee 149 22761 Hamburg Germany

We describe the development of a broadband astro-comb providing wavelength coverage of 500 - 620 nm, which is deployed as a wavelength calibration source for the HARPS-N spectrograph to detect and characterize long-pe... 详细信息

ISBN: (纸本)9781557529824

关键词： Spectrographs

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Optical generation, templating, and polymerization of three-dimensional arrays of liquid-crystal defects decorated by plasmonic nanoparticles

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Physical Review E 2013年第3期87卷 032503-032503页

作者： Julian S. Evans Paul J. Ackerman Dirk J. Broer Jao van de Lagemaat Ivan I. Smalyukh Department of Physics and Materials Science and Engineering Program University of Colorado at Boulder Boulder Colorado 80309 USA Department of Electrical Computer and Energy Engineering and Liquid Crystals Materials Research Center University of Colorado at Boulder Boulder Colorado 80309 USA National Renewable Energy Laboratory Golden Colorado 80401 USA Functional Organic Materials and Devices Eindhoven University of Technology Box 513 5600 MB Eindhoven The Netherlands Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado at Boulder Boulder Colorado 80309 USA

Defects in liquid crystals are used to model topological entities ranging from Skyrmions in high-energy physics to early-universe cosmic strings, as well as find practical applications in self-assembly of diffraction gratings and in scaffolding of plasmonic nanoparticles, but they are hard to control and organize into three-dimensional lattices. We laterally scan focused laser beams to produce periodic arrays of twist-stabilized defects forming either linear (fingers) or axially symmetric (torons) configurations in partially polymerizable liquid crystal films. Polymerization allows for stabilization of these structures and the formation of three-dimensional arrays of defects by stacking of the thin cholesteric films on top of each other. In the process of fabrication of such arrays, we polymerize the liquid crystal film with an array of torons or fingers and then sequentially produce and photopolymerize new liquid crystal layers on top of it, thus obtaining a three-dimensional structure of twist-stabilized defects in a layer-by-layer fashion. Templating by the polymerized layer spontaneously yields ordered organization of fingers and torons in the new cholesteric layer, thus enabling a three-dimensional ordered structure of defects. Nondestructive three-dimensional imaging of director fields by use of three-photon excitation fluorescence polarizing microscopy reveals the nature of topological singularities and physical underpinnings behind the observed templating effect. Three-dimensional patterning of defects templates the self-assembly of plasmonic nanoparticles into individual singularities and their arrays, laying the groundwork for potential applications in nanophotonics, plasmonics, metamaterial fabrication, and nanoscale energy conversion.

关键词： Self assembly

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Secret key generation for correlated gaussian sources

Secret key generation for correlated gaussian sources

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作者： Nitinawarat, Sirin Narayan, Prakash Department of Electrical and Computer Engineering Coordinated Science Laboratory University of Illinois Urbana IL 61801 United States Department of Electrical and Computer Engineering Institute for Systems Research University of Maryland College Park MD 20742 United States

Secret key generation by multiple terminals is considered based on their observations of jointly distributed Gaussian signals, followed by public communication among themselves. Exploiting an inherent connection between secrecy generation and lossy data compression, two main contributions are made. The first is a characterization of strong secret key capacity, and entails a converse proof technique that is valid for real-valued (and not necessarily Gaussian) as well as finite-valued signals. The capacity formula acquires a simple form when the terminals observe "symmetrically correlated" jointly Gaussian signals. For the latter setup with two terminals, considering schemes that involve quantization at one terminal, the best rate of an achievable secret key is characterized as a function of quantization rate;secret key capacity is attained as the quantization rate tends to infinity. Structured codes are shown to attain the optimum tradeoff between secret key rate and quantization rate, constituting our second main contribution. © 2012 IEEE.

关键词： Gaussian distribution

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The AAAI-13 conference workshops

The AAAI-13 conference workshops

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作者： Agrawal, Vikas Archibald, Christopher Bhatt, Mehul Bui, Hung Cook, Diane J. Cortés, Juan Geib, Christopher Gogate, Vibhav Guesgen, Hans W. Jannach, Dietmar Johanson, Michael Kersting, Kristian Konidaris, George Kotthoff, Lars Michalowski, Martin Natarajan, Sriraam O'Sullivan, Barry Pickett, Marc Podobnik, Vedran Poole, David Shastri, Lokendra Shehu, Amarda Sukthankar, Gita IBM Research India Mississippi State University United States University of Bremen Germany Laboratory for Natural Language Understanding Sunnyvale CA United States Washington State University United States University of Toulouse France Drexel University United States Department of Computer Science University of Texas Dallas United States Massey University New Zealand TU Dortmund Germany University of Alberta in Edmonton Canada Fraunhofer IAIS and the University of Bonn Germany MIT United States INSIGHT Centre for Data Analytics University College Cork Ireland Adventium Labs Minneapolis MN United States Indiana University Bloomington IN United States Naval Research Laboratory Washington DC United States Telecommunication Department of the Faculty of Electrical Engineering and Computing University of Zagreb Croatia Department of Computer Science University of British Columbia Vancouver Canada Infosys India George Mason University United States University of Central Florida United States

The AAAI-13 Workshop Program, a part of the 27th AAAI Conference on Artificial Intelligence, was held Sunday and Monday, July 14-15, 2013, at the Hyatt Regency Bellevue Hotel in Bellevue, Washington, USA. The program included 12 workshops covering a wide range of topics in artificial intelligence, including Activity Context-Aware System Architectures (WS-13-05);Artificial Intelligence and Robotics Methods in Computational Biology (WS-13-06);Combining Constraint Solving with Mining and Learning (WS-13-07);computer Poker and Imperfect Information (WS-13-08);Expanding the Boundaries of Health Informatics Using Artificial Intelligence (WS-13-09);Intelligent Robotic systems (WS-13-10);Intelligent Techniques for Web Personalization and Recommendation (WS- 13-11);Learning Rich Representations from Low-Level Sensors (WS-13-12);Plan, Activity, and Intent Recognition (WS-13-13);Space, Time, and Ambient Intelligence (WS-13-14);Trading Agent Design and Analysis (WS-13-15);and Statistical Relational Artificial Intelligence (WS-13-16). Copyright © 2013, Association for the Advancement of Artificial Intelligence. All rights reserved.

关键词： Data mining

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Radar chirp waveform selection and circuit optimization using ACPR load-pull measurements

Radar chirp waveform selection and circuit optimization usin...

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2012 IEEE 13th Annual Wireless and Microwave Technology Conference, WAMICON 2012

作者： Martin, Josh Moldovan, Matthew Baylis, Charles Marks II, Robert J. Cohen, Lawrence De Graaf, Jean Wireless and Microwave Circuits and Systems Program Department of Electrical and Computer Engineering Baylor University Waco TX United States U.S. Naval Research Laboratory Radar Division Washington DC United States

ISBN: (纸本)9781467301299

Due to tightening spectral criteria, joint optimization of radar transmitter waveform and circuit is considered to minimize the nonlinearity and waveform induced spectral spreading of radar transmitters. This work demonstrates the ACPR load-pull measurement of a power amplifier under excitation from two chirp waveforms. The results are compared to allow selection of the optimum chirp and transmitter load impedance. This work represents a beginning effort toward the real-time, computationally intelligent transmitter optimization in future reconfigurable radar systems. © 2012 IEEE.

关键词： Power amplifiers

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