A Study on the Basics of Quantum Computing
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Compton Scattering from the Deuteron at Low Energies
SE0200264 LUNFD6-NFFR-1018 Compton Scattering from the Deuteron at Low Energies Magnus Lundin Department of Physics Lund University 2002 W' •sii" Compton spridning från deuteronen vid låga energier (populärvetenskaplig sammanfattning på svenska) Vid Compton spridning sprids fotonen elastiskt, dvs. utan att förlora energi, mot en annan partikel eller kärna. Kärnorna som användes i detta försök består av en proton och en neutron (sk. deuterium, eller tungt väte). Kärnorna bestrålades med fotoner av kända energier och de spridda fo- tonerna detekterades mha. stora Nal-detektorer som var placerade i olika vinklar runt strålmålet. Försöket utfördes under 8 veckor och genom att räkna antalet fotoner som kärnorna bestålades med och antalet spridda fo- toner i de olika detektorerna, kan sannolikheten för att en foton skall spridas bestämmas. Denna sannolikhet jämfördes med en teoretisk modell som beskriver sannolikheten för att en foton skall spridas elastiskt mot en deuterium- kärna. Eftersom protonen och neutronen består av kvarkar, vilka har en elektrisk laddning, kommer dessa att sträckas ut då de utsätts för ett elek- triskt fält (fotonen), dvs. de polariseras. Värdet (sannolikheten) som den teoretiska modellen ger, beror på polariserbarheten hos protonen och neu- tronen i deuterium. Genom att beräkna sannolikheten för fotonspridning för olika värden av polariserbarheterna, kan man se vilket värde som ger bäst överensstämmelse mellan modellen och experimentella data. Det är speciellt neutronens polariserbarhet som är av intresse, och denna kunde bestämmas i detta arbete. Organization Document name LUND UNIVERSITY DOCTORAL DISSERTATION Department of Physics Date of issue 2002.04.29 Division of Nuclear Physics Box 118 Sponsoring organization SE-22100 Lund Sweden Author (s) Magnus Lundin Title and subtitle Compton Scattering from the Deuteron at Low Energies Abstract A series of three Compton scattering experiments on deuterium have been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. -
Invention, Intension and the Limits of Computation
Minds & Machines { under review (final version pre-review, Copyright Minds & Machines) Invention, Intension and the Limits of Computation Hajo Greif 30 June, 2020 Abstract This is a critical exploration of the relation between two common as- sumptions in anti-computationalist critiques of Artificial Intelligence: The first assumption is that at least some cognitive abilities are specifically human and non-computational in nature, whereas the second assumption is that there are principled limitations to what machine-based computation can accomplish with respect to simulating or replicating these abilities. Against the view that these putative differences between computation in humans and machines are closely re- lated, this essay argues that the boundaries of the domains of human cognition and machine computation might be independently defined, distinct in extension and variable in relation. The argument rests on the conceptual distinction between intensional and extensional equivalence in the philosophy of computing and on an inquiry into the scope and nature of human invention in mathematics, and their respective bearing on theories of computation. Keywords Artificial Intelligence · Intensionality · Extensionality · Invention in mathematics · Turing computability · Mechanistic theories of computation This paper originated as a rather spontaneous and quickly drafted Computability in Europe conference submission. It grew into something more substantial with the help of the CiE review- ers and the author's colleagues in the Philosophy of Computing Group at Warsaw University of Technology, Paula Quinon and Pawe lStacewicz, mediated by an entry to the \Caf´eAleph" blog co-curated by Pawe l. Philosophy of Computing Group, International Center for Formal Ontology (ICFO), Warsaw University of Technology E-mail: [email protected] https://hajo-greif.net; https://tinyurl.com/philosophy-of-computing 2 H. -
Limits on Efficient Computation in the Physical World
Limits on Efficient Computation in the Physical World by Scott Joel Aaronson Bachelor of Science (Cornell University) 2000 A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Computer Science in the GRADUATE DIVISION of the UNIVERSITY of CALIFORNIA, BERKELEY Committee in charge: Professor Umesh Vazirani, Chair Professor Luca Trevisan Professor K. Birgitta Whaley Fall 2004 The dissertation of Scott Joel Aaronson is approved: Chair Date Date Date University of California, Berkeley Fall 2004 Limits on Efficient Computation in the Physical World Copyright 2004 by Scott Joel Aaronson 1 Abstract Limits on Efficient Computation in the Physical World by Scott Joel Aaronson Doctor of Philosophy in Computer Science University of California, Berkeley Professor Umesh Vazirani, Chair More than a speculative technology, quantum computing seems to challenge our most basic intuitions about how the physical world should behave. In this thesis I show that, while some intuitions from classical computer science must be jettisoned in the light of modern physics, many others emerge nearly unscathed; and I use powerful tools from computational complexity theory to help determine which are which. In the first part of the thesis, I attack the common belief that quantum computing resembles classical exponential parallelism, by showing that quantum computers would face serious limitations on a wider range of problems than was previously known. In partic- ular, any quantum algorithm that solves the collision problem—that of deciding whether a sequence of n integers is one-to-one or two-to-one—must query the sequence Ω n1/5 times. -
7. Gamma and X-Ray Interactions in Matter
Photon interactions in matter Gamma- and X-Ray • Compton effect • Photoelectric effect Interactions in Matter • Pair production • Rayleigh (coherent) scattering Chapter 7 • Photonuclear interactions F.A. Attix, Introduction to Radiological Kinematics Physics and Radiation Dosimetry Interaction cross sections Energy-transfer cross sections Mass attenuation coefficients 1 2 Compton interaction A.H. Compton • Inelastic photon scattering by an electron • Arthur Holly Compton (September 10, 1892 – March 15, 1962) • Main assumption: the electron struck by the • Received Nobel prize in physics 1927 for incoming photon is unbound and stationary his discovery of the Compton effect – The largest contribution from binding is under • Was a key figure in the Manhattan Project, condition of high Z, low energy and creation of first nuclear reactor, which went critical in December 1942 – Under these conditions photoelectric effect is dominant Born and buried in • Consider two aspects: kinematics and cross Wooster, OH http://en.wikipedia.org/wiki/Arthur_Compton sections http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=22551 3 4 Compton interaction: Kinematics Compton interaction: Kinematics • An earlier theory of -ray scattering by Thomson, based on observations only at low energies, predicted that the scattered photon should always have the same energy as the incident one, regardless of h or • The failure of the Thomson theory to describe high-energy photon scattering necessitated the • Inelastic collision • After the collision the electron departs -
The Limits of Knowledge: Philosophical and Practical Aspects of Building a Quantum Computer
1 The Limits of Knowledge: Philosophical and practical aspects of building a quantum computer Simons Center November 19, 2010 Michael H. Freedman, Station Q, Microsoft Research 2 • To explain quantum computing, I will offer some parallels between philosophical concepts, specifically from Catholicism on the one hand, and fundamental issues in math and physics on the other. 3 Why in the world would I do that? • I gave the first draft of this talk at the Physics Department of Notre Dame. • There was a strange disconnect. 4 The audience was completely secular. • They couldn’t figure out why some guy named Freedman was talking to them about Catholicism. • The comedic potential was palpable. 5 I Want To Try Again With a rethought talk and broader audience 6 • Mathematics and Physics have been in their modern rebirth for 600 years, and in a sense both sprang from the Church (e.g. Roger Bacon) • So let’s compare these two long term enterprises: - Methods - Scope of Ideas 7 Common Points: Catholicism and Math/Physics • Care about difficult ideas • Agonize over systems and foundations • Think on long time scales • Safeguard, revisit, recycle fruitful ideas and methods Some of my favorites Aquinas Dante Lully Descartes Dali Tolkien • Lully may have been the first person to try to build a computer. • He sought an automated way to distinguish truth from falsehood, doctrine from heresy 8 • Philosophy and religion deal with large questions. • In Math/Physics we also have great overarching questions which might be considered the social equals of: Omniscience, Free Will, Original Sin, and Redemption. -
Thermodynamics of Computation and Linear Stability Limits of Superfluid Refrigeration of a Model Computing Array
Thermodynamics of computation and linear stability limits of superfluid refrigeration of a model computing array Michele Sciacca1;6 Antonio Sellitto2 Luca Galantucci3 David Jou4;5 1 Dipartimento di Scienze Agrarie e Forestali, Universit`adi Palermo, Viale delle Scienze, 90128 Palermo, Italy 2 Dipartimento di Ingegneria Industriale, Universit`adi Salerno, Campus di Fisciano, 84084, Fisciano, Italy 3 Joint Quantum Centre (JQC) DurhamNewcastle, and School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom 4 Departament de F´ısica,Universitat Aut`onomade Barcelona, 08193 Bellaterra, Catalonia, Spain 5Institut d'Estudis Catalans, Carme 47, Barcelona 08001, Catalonia, Spain 6 Istituto Nazionale di Alta Matematica, Roma 00185 , Italy Abstract We analyze the stability of the temperature profile of an array of computing nanodevices refrigerated by flowing superfluid helium, under variations of temperature, computing rate, and barycentric velocity of helium. It turns out that if the variation of dissipated energy per bit with respect to temperature variations is higher than some critical values, proportional to the effective thermal conductivity of the array, then the steady-state temperature profiles become unstable and refrigeration efficiency is lost. Furthermore, a restriction on the maximum rate of variation of the local computation rate is found. Keywords: Stability analysis; Computer refrigeration; Superfluid helium; Thermodynamics of computation. AMS Subject Classifications: 76A25, (Superfluids (classical aspects)) 80A99. (all'interno di Thermodynamics and heat transfer) 1 Introduction Thermodynamics of computation [1], [2], [3], [4] is a major field of current research. On practical grounds, a relevant part of energy consumption in computers is related to refrigeration costs; indeed, heat dissipation in very miniaturized chips is one of the limiting factors in computation. -
Quantum Information Science and the Technology Frontier Jake Taylor February 5Th, 2020
Quantum Information Science and the Technology Frontier Jake Taylor February 5th, 2020 Office of Science and Technology Policy www.whitehouse.gov/ostp www.ostp.gov @WHOSTP Photo credit: Lloyd Whitman The National Quantum Initiative Signed Dec 21, 2018 11 years of sustained effort DOE: new centers working with the labs, new programs NSF: new academic centers NIST: industrial consortium, expand core programs Coordination: NSTC combined with a National Coordination Office and an external Advisory committee 2 National Science and Technology Council • Subcommittee on Quantum Information Science (SCQIS) • DoE, NSF, NIST co-chairs • Coordinates NQI, other research activities • Subcommittee on Economic and Security Implications of Quantum Science (ESIX) • DoD, DoE, NSA co-chairs • Civilian, IC, Defense conversation space 3 Policy Recommendations • Focus on a science-first approach that aims to identify and solve Grand Challenges: problems whose solutions enable transformative scientific and industrial progress; • Build a quantum-smart and diverse workforce to meet the needs of a growing field; • Encourage industry engagement, providing appropriate mechanisms for public-private partnerships; • Provide the key infrastructure and support needed to realize the scientific and technological opportunities; • Drive economic growth; • Maintain national security; and • Continue to develop international collaboration and cooperation. 4 Quantum Sensing Accuracy via physical law New modalities of measurement Concept: atoms are indistinguishable. Use Challenge: measuring inside the body. Use this to create time standards, enables quantum behavior of individual nuclei to global navigation. image magnetic resonances (MRI) Concept: speed of light is constant. Use this Challenge: estimating length limited by ‘shot to measure distance using a time standard. noise’ (individual photons!). -
The Limits of Computation & the Computation of Limits: Towards New Computational Architectures
The Limits of Computation & The Computation of Limits: Towards New Computational Architectures An Intensive Program Proposal for Spring/Summer of 2012 Assoc. Prof. Ahmet KOLTUKSUZ, Ph.D. Yaşar University School of Engineering, Dept. Of Computer Engineering Izmir, Turkey The Aim & Rationale To disseminate the acculuted information and knowledge on the limits of the science of computation in such a compact and organized way that no any single discipline and/or department offers in their standard undergrad or graduate curriculums. While the department of Physics evalute the limits of computation in terms of the relative speed of electrons, resistance coefficient of the propagation IC and whether such an activity takes place in a Newtonian domain or in Quantum domain with the Planck measures, It is the assumptions of Leibnitz and Gödel’s incompleteness theorem or even Kolmogorov complexity along with Chaitin for the department of Mathematics. On the other hand, while the department Computer Science would like to find out, whether it is possible to find an algorithm to compute the shortest path in between two nodes of a lattice before the end of the universe, the departments of both Software Engineering and Computer Engineering is on the job of actually creating a Turing machine with an appropriate operating system; which will be executing that long without rolling off to the pitfalls of indefinite loops and/or of indefinite postponoments in its process & memory management routines while having multicore architectures doing parallel execution. All the problems, stemming from the limits withstanding, the new three and possibly more dimensional topological paradigms to the architectures of both hardware and software sound very promising and therefore worth closely examining. -
American Leadership in Quantum Technology Joint Hearing
AMERICAN LEADERSHIP IN QUANTUM TECHNOLOGY JOINT HEARING BEFORE THE SUBCOMMITTEE ON RESEARCH AND TECHNOLOGY & SUBCOMMITTEE ON ENERGY COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY HOUSE OF REPRESENTATIVES ONE HUNDRED FIFTEENTH CONGRESS FIRST SESSION OCTOBER 24, 2017 Serial No. 115–32 Printed for the use of the Committee on Science, Space, and Technology ( Available via the World Wide Web: http://science.house.gov U.S. GOVERNMENT PUBLISHING OFFICE 27–671PDF WASHINGTON : 2018 For sale by the Superintendent of Documents, U.S. Government Publishing Office Internet: bookstore.gpo.gov Phone: toll free (866) 512–1800; DC area (202) 512–1800 Fax: (202) 512–2104 Mail: Stop IDCC, Washington, DC 20402–0001 COMMITTEE ON SCIENCE, SPACE, AND TECHNOLOGY HON. LAMAR S. SMITH, Texas, Chair FRANK D. LUCAS, Oklahoma EDDIE BERNICE JOHNSON, Texas DANA ROHRABACHER, California ZOE LOFGREN, California MO BROOKS, Alabama DANIEL LIPINSKI, Illinois RANDY HULTGREN, Illinois SUZANNE BONAMICI, Oregon BILL POSEY, Florida ALAN GRAYSON, Florida THOMAS MASSIE, Kentucky AMI BERA, California JIM BRIDENSTINE, Oklahoma ELIZABETH H. ESTY, Connecticut RANDY K. WEBER, Texas MARC A. VEASEY, Texas STEPHEN KNIGHT, California DONALD S. BEYER, JR., Virginia BRIAN BABIN, Texas JACKY ROSEN, Nevada BARBARA COMSTOCK, Virginia JERRY MCNERNEY, California BARRY LOUDERMILK, Georgia ED PERLMUTTER, Colorado RALPH LEE ABRAHAM, Louisiana PAUL TONKO, New York DRAIN LAHOOD, Illinois BILL FOSTER, Illinois DANIEL WEBSTER, Florida MARK TAKANO, California JIM BANKS, Indiana COLLEEN HANABUSA, Hawaii ANDY BIGGS, Arizona CHARLIE CRIST, Florida ROGER W. MARSHALL, Kansas NEAL P. DUNN, Florida CLAY HIGGINS, Louisiana RALPH NORMAN, South Carolina SUBCOMMITTEE ON RESEARCH AND TECHNOLOGY HON. BARBARA COMSTOCK, Virginia, Chair FRANK D. LUCAS, Oklahoma DANIEL LIPINSKI, Illinois RANDY HULTGREN, Illinois ELIZABETH H. -
The Intractable and the Undecidable - Computation and Anticipatory Processes
International JournalThe Intractable of Applied and Research the Undecidable on Information - Computation Technology and Anticipatory and Computing Processes DOI: Mihai Nadin The Intractable and the Undecidable - Computation and Anticipatory Processes Mihai Nadin Ashbel Smith University Professor, University of Texas at Dallas; Director, Institute for Research in Anticipatory Systems. Email id: [email protected]; www.nadin.ws Abstract Representation is the pre-requisite for any form of computation. To understand the consequences of this premise, we have to reconsider computation itself. As the sciences and the humanities become computational, to understand what is processed and, moreover, the meaning of the outcome, becomes critical. Focus on big data makes this understanding even more urgent. A fast growing variety of data processing methods is making processing more effective. Nevertheless these methods do not shed light on the relation between the nature of the process and its outcome. This study in foundational aspects of computation addresses the intractable and the undecidable from the perspective of anticipation. Representation, as a specific semiotic activity, turns out to be significant for understanding the meaning of computation. Keywords: Anticipation, complexity, information, representation 1. INTRODUCTION As intellectual constructs, concepts are compressed answers to questions posed in the process of acquiring and disseminating knowledge about the world. Ill-defined concepts are more a trap into vacuous discourse: they undermine the gnoseological effort, i.e., our attempt to gain knowledge. This is why Occam (to whom the principle of parsimony is attributed) advised keeping them to the minimum necessary. Aristotle, Maimonides, Duns Scotus, Ptolemy, and, later, Newton argued for the same. -
Compton Effect
Module 5 : MODERN PHYSICS Lecture 25 : Compton Effect Objectives In this course you will learn the following Scattering of radiation from an electron (Compton effect). Compton effect provides a direct confirmation of particle nature of radiation. Why photoelectric effect cannot be exhited by a free electron. Compton Effect Photoelectric effect provides evidence that energy is quantized. In order to establish the particle nature of radiation, it is necessary that photons must carry momentum. In 1922, Arthur Compton studied the scattering of x-rays of known frequency from graphite and looked at the recoil electrons and the scattered x-rays. According to wave theory, when an electromagnetic wave of frequency is incident on an atom, it would cause electrons to oscillate. The electrons would absorb energy from the wave and re-radiate electromagnetic wave of a frequency . The frequency of scattered radiation would depend on the amount of energy absorbed from the wave, i.e. on the intensity of incident radiation and the duration of the exposure of electrons to the radiation and not on the frequency of the incident radiation. Compton found that the wavelength of the scattered radiation does not depend on the intensity of incident radiation but it depends on the angle of scattering and the wavelength of the incident beam. The wavelength of the radiation scattered at an angle is given by .where is the rest mass of the electron. The constant is known as the Compton wavelength of the electron and it has a value 0.0024 nm. The spectrum of radiation at an angle consists of two peaks, one at and the other at . -
Compton Scattering from Low to High Energies
Compton Scattering from Low to High Energies Marc Vanderhaeghen College of William & Mary / JLab HUGS 2004 @ JLab, June 1-18 2004 Outline Lecture 1 : Real Compton scattering on the nucleon and sum rules Lecture 2 : Forward virtual Compton scattering & nucleon structure functions Lecture 3 : Deeply virtual Compton scattering & generalized parton distributions Lecture 4 : Two-photon exchange physics in elastic electron-nucleon scattering …if you want to read more details in preparing these lectures, I have primarily used some review papers : Lecture 1, 2 : Drechsel, Pasquini, Vdh : Physics Reports 378 (2003) 99 - 205 Lecture 3 : Guichon, Vdh : Prog. Part. Nucl. Phys. 41 (1998) 125 – 190 Goeke, Polyakov, Vdh : Prog. Part. Nucl. Phys. 47 (2001) 401 - 515 Lecture 4 : research papers , field in rapid development since 2002 1st lecture : Real Compton scattering on the nucleon & sum rules IntroductionIntroduction :: thethe realreal ComptonCompton scatteringscattering (RCS)(RCS) processprocess ε, ε’ : photon polarization vectors σ, σ’ : nucleon spin projections Kinematics in LAB system : shift in wavelength of scattered photon Compton (1923) ComptonCompton scatteringscattering onon pointpoint particlesparticles Compton scattering on spin 1/2 point particle (Dirac) e.g. e- Klein-Nishina (1929) : Thomson term ΘL = 0 Compton scattering on spin 1/2 particle with anomalous magnetic moment Stern (1933) Powell (1949) LowLow energyenergy expansionexpansion ofof RCSRCS processprocess Spin-independent RCS amplitude note : transverse photons : Low