Frontiers in Optics 2008 Laser Science XXV
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Is the Universe Expanding?: an Historical and Philosophical Perspective for Cosmologists Starting Anew
Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 6-1996 Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew David A. Vlosak Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Cosmology, Relativity, and Gravity Commons Recommended Citation Vlosak, David A., "Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew" (1996). Master's Theses. 3474. https://scholarworks.wmich.edu/masters_theses/3474 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. IS THEUN IVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STAR TING ANEW by David A Vlasak A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements forthe Degree of Master of Arts Department of Philosophy Western Michigan University Kalamazoo, Michigan June 1996 IS THE UNIVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STARTING ANEW David A Vlasak, M.A. Western Michigan University, 1996 This study addresses the problem of how scientists ought to go about resolving the current crisis in big bang cosmology. Although this problem can be addressed by scientists themselves at the level of their own practice, this study addresses it at the meta level by using the resources offered by philosophy of science. There are two ways to resolve the current crisis. -
Emil Wolf Institutional Interviews Journal Interviews EMERGING RESEARCH FRONTS - 2009 Podcasts
Home About Scientific Press Room Contact Us ● ScienceWatch Home ● Inside This Month... ● Interviews Featured Interviews Author Commentaries 2009 : April 2009 - Emerging Research Fronts : Emil Wolf Institutional Interviews Journal Interviews EMERGING RESEARCH FRONTS - 2009 Podcasts April 2009 ● Analyses Emil Wolf talks with ScienceWatch.com and answers a few questions about this month's Featured Analyses Emerging Research Front Paper in the field of Physics. What's Hot In... Article: Unified theory of coherence and polarization of random Special Topics electromagnetic beams Authors: Wolf, E Journal: PHYS LETT A, 312 (5-6): 263-267 JUN 16 2003 ● Data & Rankings Addresses: Univ Rochester, Dept Phys & Astron, 601 Elmwood Ave, Rochester, NY 14627 USA. Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. Sci-Bytes Univ Rochester, Inst Opt, Rochester, NY 14627 USA. Fast Breaking Papers New Hot Papers Emerging Research Fronts Fast Moving Fronts Corporate Research Fronts Why do you think your paper is highly cited? Research Front Maps Because the theory presented in that paper makes it possible to provide solutions to a number of scientific, technological, and medical problems which could not have been done previously. Current Classics Top Topics Does it describe a new discovery, methodology, or synthesis of knowledge? Rising Stars The discovery reported in the paper provides a synthesis of two branches of optics, known as the theory of coherence and the theory of polarization of light. Until the publication of my paper, these two subjects New Entrants had always been treated independently of each other. Prior to the invention of the laser, almost 50 years Country Profiles ago, the available sources which generate light, such as a light bulb and the sun, may be shown to have, on a short time scale, irregularities (called fluctuations) which make it impossible to use such light for some applications. -
Ionization Based State Read out of a Single 87-Rb Atom
Ionization Based State Read Out of a single 87Rb Atom Michael Krug M¨unchen2017 Ionization Based State Read Out of a single 87Rb Atom Michael Krug Dissertation an der Fakult¨atf¨urPhysik der Ludwig{Maximilians{Universit¨at M¨unchen vorgelegt von Michael Krug aus M¨unchen M¨unchen, den 8. Dezember 2017 Erstgutachter: Prof. Dr. Harald Weinfurter Zweitgutachter: Prof. J¨orgSchreiber Tag der m¨undlichen Pr¨ufung:30. Januar 2018 "After sleeping through a hundred million centuries we have finally opened our eyes on a sumptuous planet sparkling with color, bountiful with life. Within decades, we must close our eyes again. Isn't it a noble, enlightened way of spending our brief time in the sun to work at understanding the universe and how we have come to wake up in it? This is how I answer when I am asked, as I am surprisingly often, why I bother to get up in the mornings." Richard Dawkins Zusammenfassung Verschr¨ankung ist nach E. Schr¨odingerdie fundamentale Charakteristik der 1 Quantenmechanik. Einerseits lebt ein verschr¨ankterZustand zweiter Spin- 2 -Teilchen auf einem vier-dimensionalem Hilbert-Raum und die Theorie, um diesen Zustand zu beschreiben, ist hinreichend verstanden. Auf der anderen Seite ist die experimentelle Realisierung verschr¨ankter Systeme, im Besonderen hybride Licht-Materie-Systeme und deren Nachweis noch immer ein anspruchsvoller Prozess. Ausgehend von einem Quantensystem, das aus einem verschr¨anktenAtom-Photon-Paar besteht, wird hier die experimentelle Anwendung des entanglement swapping Protokolls verwendet, um einen Grundknotenpunkt einer Quanten-Repeater Verbindung aufzubauen, die aus zwei verschr¨anktenAtomen besteht. Die angek¨undigteErzeugung von Ver- schr¨ankungzwischen zwei Atomen bereitet den Weg hin zu einem beweiskr¨aftigem Experiment, um eine lokal-realistische Beschreibung der Welt zu falsifizieren. -
Photons That Travel in Free Space Slower Than the Speed of Light Authors
Title: Photons that travel in free space slower than the speed of light Authors: Daniel Giovannini1†, Jacquiline Romero1†, Václav Potoček1, Gergely Ferenczi1, Fiona Speirits1, Stephen M. Barnett1, Daniele Faccio2, Miles J. Padgett1* Affiliations: 1 School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ, UK 2 School of Engineering and Physical Sciences, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, UK † These authors contributed equally to this work. * Correspondence to: [email protected] Abstract: That the speed of light in free space is constant is a cornerstone of modern physics. However, light beams have finite transverse size, which leads to a modification of their wavevectors resulting in a change to their phase and group velocities. We study the group velocity of single photons by measuring a change in their arrival time that results from changing the beam’s transverse spatial structure. Using time-correlated photon pairs we show a reduction of the group velocity of photons in both a Bessel beam and photons in a focused Gaussian beam. In both cases, the delay is several microns over a propagation distance of the order of 1 m. Our work highlights that, even in free space, the invariance of the speed of light only applies to plane waves. Introducing spatial structure to an optical beam, even for a single photon, reduces the group velocity of the light by a readily measurable amount. One sentence summary: The group velocity of light in free space is reduced by controlling the transverse spatial structure of the light beam. Main text The speed of light is trivially given as �/�, where � is the speed of light in free space and � is the refractive index of the medium. -
Arxiv:1603.00726V1 [Physics.Optics] 2 Mar 2016
Single-pixel 3D imaging with time-based depth resolution Ming-Jie Sun,1, 2, ∗ Matthew. P. Edgar,2 Graham M. Gibson,2 Baoqing Sun,2 Neal Radwell,2 Robert Lamb,3 and Miles J. Padgett2, y 1Department of Opto-electronic Engineering, Beihang University, Beijing, 100191, China 2SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK 3Selex ES, Edinburgh, UK Time-of-flight three dimensional imaging is an important tool for many applications, such as object recognition and remote sensing. Unlike conventional imaging approach using pixelated detector array, single-pixel imaging based on projected patterns, such as Hadamard patterns, utilises an alternative strategy to acquire information with sampling basis. Here we show a modified single-pixel camera using a pulsed illumi- nation source and a high-speed photodiode, capable of reconstructing 128×128 pixel resolution 3D scenes to an accuracy of ∼ 3 mm at a range of ∼ 5 m. Furthermore, we demonstrate continuous real-time 3D video with a frame-rate up to 12 Hz. The sim- plicity of the system hardware could enable low-cost 3D imaging devices for precision ranging at wavelengths beyond the visible spectrum. Introduction Whilst a variety of 3D imaging technologies are suited for different applications, time-of-flight (TOF) systems have set the benchmark for performance with regards to a combination of accuracy and operating range. Time-of-flight imaging is performed by illuminating a scene with a pulsed light source and observing the back-scattered light. Correlating the detection time of the back-scattered light with the time of the illumination pulse allows the distance, d, to objects within the scene to be estimated by d = tc=2, where t is the TOF and c is the propagation speed of light. -
Acknowledgements Acknowl
1277 Acknowledgements Acknowl. A.1 The Properties of Light by Helen Wächter, Markus W. Sigrist by Richard Haglund The authors thank a number of coworkers for their The author thanks Prof. Emil Wolf for helpful discus- valuable input, notably R. Bartlome, Dr. C. Fischer, sions, and gratefully acknowledges the financial support D. Marinov, Dr. J. Rey, M. Stahel, and Dr. D. Vogler. of a Senior Scientist Award from the Alexander von The financial support by the Swiss National Science Humboldt Foundation and of the Medical Free-Electron Foundation and ETH Zurich for the isotopomer studies Laser program of the Department of Defense (Con- is gratefully acknowledged. tract F49620-01-1-0429) during the preparation of this chapter. by Jürgen Helmcke In writing the chapter on frequency-stabilized lasers, A.4 Nonlinear Optics the author has greatly benefited from fruitful coopera- by Aleksei Zheltikov, Anne L’Huillier, Ferenc Krausz tion and helpful discussions with his colleagues at PTB, We acknowledge the support of the European Com- in particular with Drs. Fritz Riehle, Harald Schnatz, munity’s Human Potential Programme under contract Uwe Sterr, and Harald Telle. Special thanks belong to HPRN-CT-2000-00133 (ATTO) and the Swedish Sci- Dr. Fritz Riehle for his careful and critical reading of the ence Council. manuscript. Part of the work discussed in this chapter was supported by the Deutsche Forschungsgemeinschaft A.5 Optical Materials and Their Properties (DFG) under SFB 407. by Klaus Bonrad The author of Sect. 5.9.2 is grateful to Dr. Thomas C.12 Femtosecond Laser Pulses: Däubler, Dr. Dirk Hertel, and Dr. -
Principles of Optics
Principles of optics Electromagnetic theory of propagation, interference and diffraction of light MAX BORN MA, Dr Phil, FRS Nobel Laureate Formerly Professor at the Universities of Göttingen and Edinburgh and EMIL WOLF PhD, DSc Wilson Professor of Optical Physics, University of Rochester, NY with contributions by A.B.BHATIA, P.C.CLEMMOW, D.GABOR, A.R.STOKES, A.M.TAYLOR, P.A.WAYMAN AND W.L.WILCOCK SEVENTH (EXPANDED) EDITION CAMBRIDGE UNIVERSITY PRESS Contents Historical introduction xxv I Basic properties of the electromagnetic field 1 1.1 The electromagnetic field 1 1.1.1 Maxwells equations 1 1.1.2 Material equations 2 1.1.3 Boundary conditions at a surface of discontinuity 4 1.1.4 The energy law of the electromagnetic field 7 1.2 The wave equation and the velocity of light 11 1.3 Scalar waves 14 1.3.1 Plane waves 15 1.3.2 Spherical waves 16 1.3.3 Harmonie waves. The phase velocity 16 1.3.4 Wave packets. The group velocity 19 1.4 Vector waves 24 1.4.1 The general electromagnetic plane wave 24 1.4.2 The harmonic electromagnetic plane wave 25 (a) Elliptic polarization 25 (b) Linear and circular polarization 29 (c) Characterization of the state of polarization by Stoltes parameters 31 1.4.3 Harmonie vector waves of arbitrary form 33 1.5 Reflection and refraction of a plane wave 38 1.5.1 The laws of reflection and refraction 38 1.5.2 Fresnel formulae 40 1.5.3 The reflectivity and transmissivity; polarization an reflection and refraction 43 1.5.4 Total reflection 49 1.6 Wave propagation in a stratified medium. -
Colloquiumcolloquium
ColloquiumColloquium History and solution of the phase problem in the theory of structure determination of crystals from X-ray diffraction experiments Emil Wolf Department of Physics and Astronomy Institute of Optics University of Rochester 3:45 pm, Wednesday, Nov 18, 2009 B.Sc. and Ph.D. Bristol University Baush & Lomb 109 D.Sc. University of Edinburgh U. of Rochester 1959 - Tea 3:30 B&L Lobby Wilson Professor of Optical Physics JointlyJointly sponsoredsponsored byby The most important researches carried out in this field will be reviewed and a recently DepartmentDepartment ofof PhysicsPhysics andand AstronomyAstronomy obtained solution of the phase problem will be presented. History and solution of the phase problem in the theory of structure determination of crystals from X-ray diffraction experiments Emil Wolf Department of Physics and Astronomy and The Institute of Optics University of Rochester Abstract Since the pioneering work of Max von Laue on interference and diffraction of X-rays carried out almost a hundred years ago, numerous attempts have been made to determine structures of crystalline media from X-ray diffraction experiments. Usefulness of all of them has been limited by the inability of measuring phases of the diffracted beams. In this talk the most important researches carried out in this field will be reviewed and a recently obtained solution of the phase problem will be presented. Biography Emil Wolf is Wilson Professor of Optical Physics at the University of Rochester, and is reknowned for his work in physical optics. He has received many awards, including the Ives Medal of the Optical Society of America, the Albert A. -
Emil Wolf: ‘A Scientist and Friend Like No Other’ a Student of the Noted Physicist Counts up Some of His Mentor’S Contributions to Science and to His Colleagues
CLASS NOTES TRIBUTE Emil Wolf: ‘A Scientist and Friend Like No Other’ A student of the noted physicist counts up some of his mentor’s contributions to science and to his colleagues. Emil Wolf, the former Wilson Professor of Optical Physics, a In 1958, Robert Hopkins, then director of the institute, traveled faculty member in the University’s Institute of Optics and the to England for a conference and to meet with Emil. The meet- 1 3 Department of Physics and Astronomy, died in June at the age ing nearly didn’t happen. The letter from Hopkins got misfiled by of 95. He is survived by his children, Bruno and Paula, and his a secretary and was only discovered by Emil as he was searching beloved wife, Marlies. He was decorated with numerous presti- for another misfiled document. “It was all a matter of luck, par- gious national and international awards, honorary degrees, and ticularly that phone call in Paris at three in the morning saying appointments. He was my mentor and my friend and my measuring stick for what is good and what is decent. He was a refugee. When the Nazis in- vaded Czechoslovakia in 1939, Emil’s 2 brother, Karel, joined the Czech army. Emil was too young for the army and their parents sent him to Italy in hopes that he could somehow get to France or England. Trading valuable stamps his father had collected, Emil made his way from Prague to the Italian coast and then illegally into France by boat. Once in Paris, he found work with the Czech government in exile with whom he evacuated to Britain when Paris fell. -
Numerical Analysis of Focusing by a Metamaterial Lens
Numerical analysis of focusing by a metamaterial lens Ali Eren Culhaoglu1, Andrey Osipov1 and Peter Russer2 1 Microwaves and Radar Institute, German Aerospace Center 82234 Wessling Germany email: [email protected] 2 Institute for High Frequency Engineering, Technische Universitat¨ Munchen¨ Arcisstrasse 21, 80333 Munich Germany email: [email protected] Abstract Over the last several years there has been a surge of interest in artificial materials because of their potential to expand the range of electromagnetic properties in materials. The so called metamate- rials, also known as left-handed (LHM) or double-negative (DNG) materials with negative permittivity and permeability have attracted growing interest. An important application area is the realization of flat superlenses with imaging properties beyond that of conventional lenses. This work investigates the focusing properties of a lossless planar DNG slab with a relative permittivity and permeability both ap- proaching the value -1. The relation between the imaging quality and the material parameters is examined both analytically and numerically. Results obtained from numerical simulations via the transmission line matrix method are compared to the analytical solution. 1. Introduction Incident and emerging waves from a DNG slab will undergo negative refraction [1]. As a consequence p a slab with finite thickness d and material parameters "r = µr = -1 (refractive index n = "rµr = -1) focuses waves emitted from a point source located at a distance l in front of the slab to a point at a distance of d − l behind the slab [2, 3]. As seen in Fig. 1(a) the waves emitted from a point source are focused inside and outside the slab due to negative refraction at the slab interfaces. -
„Unsere Musik Versteht Man Überall“
Mehr von Sieg und Rhein Festival im Kulturzentrum Kabelmetall in Schladern „Unsere Musik versteht man überall“ • Foto: Luca Goldhorn Thorsten Quaeschning von Tangerine Dream 2015 beim Schwingungen-Festival. • Foto: Tangerine Dream Die klassische Besetzung der 70er: Tangerine Dream mit Chris Franke, Peter Baumann und Edgar Froese 1974 am Planetarium in Berlin. 01/02 25.08.2016 WINDECK-SCHLADERN. Das Kulturzentrum Kabelmetal in Windeck-Schladern richtet das Festival „Schwingungen am Wasserfall“ mit Konzerten, Sessions und Vorträgen aus. Dort treten Größen der elektronischen Musikszene auf. Ein Gespräch mit Thorsten Quaeschning von Tangerine Dream. Für das Genre der elektronischen Musik gilt die 1967 gegründete Gruppe Tangerine Dream als stilprägend. Ebenso wie Kraftwerk genießen die Berliner heute noch international Anerkennung. 2015 starb Gründer Edgar Froese, der als einziger Musiker die ganze Zeit dabei war und mit vielen verschiedenen Besetzungen arbeitete. Die drei verbliebenen Musiker machen weiter und treten am Samstag, 3. September, beim Elektronik-Festival „Schwingungen am Wasserfall“ bei Kabelmetal in Windeck auf. Einer von ihnen ist Thorsten Quaeschning. Mit ihm sprach Dominik Pieper Weitere Links • Viele Besucher kommen aus dem Ausland Haben Sie sich den Entschluss leicht gemacht, ohne Edgar Froese mit Tangerine Dream weiterzumachen? Thorsten Quaeschning: Das habe ich gar nicht entschieden. Edgar hat noch zu Lebzeiten sehr genau bestimmt, wie und mit wem Tangerine Dream weitergehen soll. Er hatte einen lange vorbereiteten Plan mit dem Ziel, dass seine Vision fortgesetzt wird. Seine Frau Bianca hat nun die administrative und visuell-kreative Rolle, und musikalisch sind wir jetzt ein Trio. Hoshiko Yamane, Ulrich Schnauss, der 2014 vor unserer Australien-Tour dazu stieß, und ich. -
Arxiv:2005.03760V1 [Physics.Class-Ph] 4 May 2020
Amplification of waves from a rotating body Marion Cromb,1 Graham M. Gibson,1 Ermes Toninelli,1 Miles J. Padgett,1, ∗ Ewan M. Wright,2 and Daniele Faccio1, 2, y 1School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK 2College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA (Dated: May 11, 2020) In 1971 Zel'dovich predicted that quantum fluctuations and classical waves reflected from a ro- tating absorbing cylinder will gain energy and be amplified. This key conceptual step towards the understanding that black holes may also amplify quantum fluctuations, has not been verified ex- perimentally due to the challenging experimental requirements on the cylinder rotation rate that must be larger than the incoming wave frequency. Here we experimentally demonstrate that these conditions can be satisfied with acoustic waves. We show that low-frequency acoustic modes with orbital angular momentum are transmitted through an absorbing rotating disk and amplified by up to 30% or more when the disk rotation rate satisfies the Zel'dovich condition. These experiments address an outstanding problem in fundamental physics and have implications for future research into the extraction of energy from rotating systems. Introduction. In 1969, Roger Penrose proposed a an amplifier. Outgoing waves then have an increased am- method to extract the rotational energy of a rotating plitude, therefore extracting energy from the rotational black hole, now known as Penrose superradiance [1]. Pen- energy of the body in the same spirit of Penrose's pro- rose suggested that an advanced civilisation might one posal. day be able to extract energy from a rotating black hole Satisfying the condition in Eq.