DOCSLIB.ORG

Issues in Physics & Astronomy

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Issues in Physics & Astronomy Issues in Physics & Astronomy Board on Physics and Astronomy • The National Academies • Washington, D.C. • 202-334-3520 • national-academies.org/bpa • Summer 2008 Understanding the Impact of Selling the Helium Reserve Michael H. Moloney, BPA Staff nder the sponsorship of the monatomic element, it passes easily containing 0.3 percent helium is consid- Bureau of Land Management at through tiny orifices and is therefore used ered economically viable. A few gas Uthe Department of the Interior, for leak detection in many scientific and deposits contain as much as 8 percent the BPA, in cooperation with the Na- technical applications. Its density is only helium. By comparison, the atmosphere tional Materials Advisory Board, has 15 percent that of air, making it useful as a contains only about 0.0005 percent. He- initiated a study to understand the lifting gas for aerostats and other devices. lium from wells that produce impact on the scientific community of Its high heat capacity, along with its uneconomically low concentrations, or the continuing sale of the U.S. helium inertness, makes it the preferred quench- from wells that produce higher concentra- reserve and recent developments in the ing medium for many applications in tions but do not flow through an extrac- helium market. materials processing, such as the produc- tion plant, is often vented to the atmo- The element helium has unique tion of high-quality superalloy powders. It sphere when the natural gas is burned. A properties. Liquefying near absolute is the preferred carrier gas for gas chroma- relatively minor amount of helium also is zero, it is the only option for many tography, a widely applied technique for vented at extraction plants that have no cryogenic applications, such as cooling chemical separations. access to a helium storage facility when superconducting magnets for scientific Helium has, however, one other less excess helium production cannot be and medical instruments. In fact, cryo- desirable characteristic—it is a nonrenew- marketed. genic applications account for nearly 28 able resource. Helium is a byproduct of From 1929 until 1998, the Federal percent of annual consumption accord- purifying or liquefying natural gas. Recov- government operated helium production ing to a 2002 survey of helium uses. ering helium from a natural gas mixture See “Helium” on page 10 Being chemically inert, helium is used for pressurizing and purging fuel tanks and in breathing gas mixtures for deep- The Moment of Truth for Inertial Fusion sea diving. Because it is the smallest Riccardo Betti, University of Rochester hile the quest for controlled reaction rate. The hotter the plasma, the thermonuclear fusion energy greater the number of fusion reactions In this issue: Whas been ongoing for the last that heat the plasma. This runaway pro- half century (magnetic confinement since cess ceases when micro and/or macro • Helium Reserve Study 1950’s and laser fusion since 1960’s), instabilities of the plasma or saturation of Inauguration. Page 1 fusion research is about to reach a climax the fusion rates prevent further growth of with the construction of the National the plasma temperature. When properly • Inertial Confinement Ignition Facility (NIF) and International controlled, the amplification of the fusion Fusion. Page 1 Thermonuclear Experimental Reactor reaction rate resulting from the plasma • ITER Plan Review Report. (ITER). Conclusive tests for the physics self-heating process can lead to a fusion Page 2 of the magnetic and inertial confinement energy output many times larger than the concepts will be performed on these input energy required for bringing the • BPA Spring Meeting. ignition machines. plasma to ignition conditions. The ratio of Page 3 Technically, thermonuclear ignition is the energy output to the input is the a thermal instability, a runaway process in energy gain. • New Astronomy Survey. the thermal energy of the thermonuclear Demonstrating thermonuclear ignition Page 5 fuel—typically a 50-50 mixture of deute- and energy gains in the laboratory has • Changes at the BPA. Page 6 rium (D) and tritium (T). In an ignited DT been a goal of fusion energy research for plasma, known as a burning plasma, the decades, and it is widely considered a • Committee on Radio fraction of the energy associated with the milestone in the development of fusion Frequencies Meeting. P.7 α-particles (3.5MeV) from the fusion energy, as well as a major scientific • Solid State Sciences reactions D + T α + n + 17.6MeV is achievement. Committee Meeting. Page 7 deposited in the plasma itself thus increas- Ignition in the lab does not imply that ing its temperature and, in turn, the fusion See “Fusion” on page 8 2 BPA News • Summer 2008 Review of the Plan for U.S. Participation in ITER David B. Lang, BPA Staff I. Review the document "Planning for U.S. The NRC Committee to Review the Ed. Note: This article is largely inspired by Fusion Community Participation in the U.S. ITER Science Participation Planning the Executive Summary of the report. ITER Program." Determine whether the Process was tasked to assess the current he development of a plan for the plan provides a good initial outline for U.S. Department of Energy (DOE) plan for participation of the U.S. fusion effective participation of U.S. plasma U.S. fusion community participation in Tcommunity in the ITER program scientists in research at ITER. ITER, evaluate the plan’s elements, and was mandated by the Energy Policy Act II. Evaluate the following required ele- recommend appropriate goals, proce- of 2005 (EPAct). The EPAct, in Section ments of the plan: (1) an agenda for U.S. dures, and metrics for consideration in the 972 (c)(4)(B), also directed that, after research at ITER, (2) methodologies to future development of the plan. The completion of the plan, the U.S. Depart- evaluate ITER's contribution to progress committee found that: ment of Energy (DOE) request an external toward a power source, (3) description of • The 2006 DOE plan for U.S. participation review of its content. Accordingly, on the anticipated relationship between the in ITER is operating and has proven August 10, 2006, the DOE Under Secre- U.S. ITER research program and the effective in beginning to coordinate U.S. tary for Science submitted the completed overall U.S. fusion program. research activities and the development of plan to the National Academy of Sciences III. The committee will recommend next the ITER program. U.S. scientists have for review. In response, the National steps in the development of the plan, been well engaged in the planning for Research Council (NRC) organized a including: (a) appropriate elements and/or ITER, and the United States should committee to review the DOE plan with goals for the plan; (b) procedures to endeavor to maintain this level of activity. the following charge: facilitate further development of the plan; The plan in its current form is well aligned The committee will prepare a short and (c) metrics for measuring progress in with DOE Office of Fusion Energy Sci- report addressing the following tasks: establishing robust U.S. participation in ences goals. the ITER research program. • The U.S. ITER research program is at Committee to Review the U.S. ITER The committee was appointed on least as organizationally and technically Science Participation Planning Process October 1, 2007 and met in Washington, mature as that of the other ITER partici- D.C. on December 14-15, 2007. Soon after, pants at the time of this writing. Patrick L. Colestock, Chair the FY2008 Consolidated Appropriations • The U.S. research program for ITER as Los Alamos National Laboratory Act became law, under which U.S. contri- described in the DOE plan is appropriate butions for ITER were unexpectedly and justified, and the committee notes Roger D. Bengtson eliminated. Although this committee was that the domestic program will evolve as The University of Texas at Austin not specifically tasked to assess the the international research program is James E. Brau implications of the FY2008 budget, it developed. U.S. involvement in develop- University of Oregon believed that the budget would necessar- ing the research program for ITER will be Cary B. Forest ily affect U.S. researchers’ ability to crucial to the realization of U.S. fusion University of Wisconsin participate fully in the ITER project, and it research goals. Stephen Holmes therefore felt obliged to address this • The committee underscores as its great- Fermi National Accelerator Laboratory issue. est concern the uncertain U.S. commit- ITER presents the United States and ment to ITER at the present time. Fluctua- George J. Morales its international partners with the opportu- tions in the U.S. commitment to ITER will University of California at Los Angeles nity to explore new and exciting frontiers undoubtedly have a large negative impact Thomas M. O’Neil of plasma science while bringing the on the ability of the U.S. fusion commu- University of California at San Diego promise of fusion energy closer to reality. nity to influence the developing ITER Tony S. Taylor The ITER project has garnered the com- research program, to capitalize on re- General Atomics mitment and will draw on the scientific search at ITER to help achieve U.S. fusion potential of seven international partners, energy goals, to participate in obtaining Dennis G. Whyte China, the European Union, India, Japan, important scientific results on burning Massachusetts Institute of Technology the Republic of Korea, Russia, and the plasmas from ITER, and to be an effective Michael C. Zarnstorff United States, countries that represent participant in and beneficiary of future Princeton University more than half of the world’s population. international scientific collaborations. NRC Staff The success of ITER will depend on each • Consistent with previous National partner’s ability to fully engage itself in Research Council and Fusion Energy Donald C.
Load more

Recommended publications
  • Hybrid Qubits Solve Key Hurdle to Quantum Computing 28 December 2018
    Hybrid qubits solve key hurdle to quantum computing 28 December 2018 In 1998, Daniel Loss, one of the authors of the current study, came up with a proposal, along with David DiVincenzo of IBM, to build a quantum computer by using the spins of electrons embedded in a quantum dot—a small particle that behaves like an atom, but that can be manipulated, so that they are sometimes called "artificial atoms." In the time since then, Loss and his team have endeavored to build practical devices. There are a number of barriers to developing practical devices in terms of speed. First, the device must be able to be initialized quickly. Initialization is the process of putting a qubit into a certain state, and if that cannot be done rapidly it slows down the device. Second, it must maintain coherence for a time long enough to make a measurement. Coherence refers to the Schematic of the device. Credit: RIKEN entanglement between two quantum states, and ultimately this is used to make the measurement, so if qubits become decoherent due to environmental noise, for example, the device Spin-based quantum computers have the potential becomes worthless. And finally, the ultimate state to tackle difficult mathematical problems that of the qubit must be able to be quickly read out. cannot be solved using ordinary computers, but many problems remain in making these machines While a number of methods have been proposed scalable. Now, an international group of for building a quantum computer, the one proposed researchers led by the RIKEN Center for Emergent by Loss and DiVincenzo remains one of the most Matter Science have crafted a new architecture for practically feasible, as it is based on quantum computing.
    [Show full text]
  • The Quantum Times) in Producing the First in Their List of Guidelines Nor Was It Reported As Operating Laser, Are All Interesting and Enlightening
    TThhee QQuuaannttuumm TTiimmeess APS Topical Group on Quantum Information, Concepts, and Computation Summer 2007 Volume 2, Number 2 Advances & Challenges in Quantum Key Distribution Quantum Key Distribution (QKD) is the flagship success of quantum communication. Since Bennett and Brassard’s 1984 publication [2] it has given a new direction to the field. (For a review see e.g. [3].) Up to then in quantum communication, the properties of quantum mechanics were used, for example, to improve on the through-put of optical channels. With the arrival of QKD an application has been created that achieves what Inside… cannot be achieved with classical communication alone: … you will find a little bit of provably secure protocols with no assumption about the everything. We begin with an computational power of an adversary. (This scenario is referred article from Norbert Lütkenhaus on to as unconditional security, a technical term in cryptography. quantum key distribution (QKD) Still, the devices of sender and receiver are assumed to be that grew out of a news article from perfect and out of bound of the adversary, an assumption without our last issue. Norbert speaks from which no cryptography is possible at all.) It is sufficient to the standpoint of someone at the prepare non-orthogonal states as signals and to measure them at forefront of quantum cryptography the receiver’s end. Then, using an authenticated public channel, and his article should be read by both parties can distill a secret key from the data. The procedure anyone interested in the current needs to be kick-started with some secret key in order to state and future direction of QKD.
    [Show full text]
  • Topological Phases and Applications to Quantum Information Processing" ______List of Organizers
    Proposed title: "Topological Phases and Applications to Quantum Information Processing" __________________________________________________________ List of organizers: Nicholas E. Bonesteel (Florida State University and NHMFL) Phone: (850) 644-7805, E-mail: [email protected] James P. Eisenstein (Caltech) Phone: (626) 395-4649, E-mail: [email protected] Michael H. Freedman (Microsoft Research) Phone: (805) 893-6313, E-mail: [email protected] Kirill Shtengel (UC Riverside) Phone: (951) 827-1058, E-mail: [email protected] Steven H. Simon (Lucent Technologies, Bell Labs) Phone: (908) 582-6006, E-mail: [email protected] __________________________________________________________ Proposed length: 4 weeks, preferably July 2 through July 29 or June 25 through July 22. However, anytime between June 18 and Sept 2, 2007 is acceptable. Pushing it toward earlier or later dates will result in conflicts with teaching for many of the potential attendees. __________________________________________________________ Abstract: Quantum computers, if realized in practice, promise exponential speed-up of some of the computational tasks that conventional classical algorithms are intrinsically incapable of handling efficiently. Perhaps even more intriguing possibility arises from being able to use quantum computers to simulate the behavior of other physical systems -- an exciting idea dating back to Feynman. Unfortunately, realizing a quantum computer in practice proves to be very difficult, chiefly due to the debilitating effects of decoherence plaguing all possible schemes which use microscopic degrees of freedom (such as nuclear or electronic spins) as basic building blocks. >From this perspective, topological quantum computing offers an attractive alternative by encoding quantum information in nonlocal topological degrees of freedom that are intrinsically protected from decoherence due to local noise.
    [Show full text]
  • Quantum Computation with Spins in Quantum Dots
    Quantum Computation With Spins In Quantum Dots Fikeraddis Damtie June 10, 2013 1 Introduction Physical implementation of quantum computating has been an active area of research since the last couple of decades. In classical computing, the transmission and manipulation of classical information is carried out by physical machines (computer hardwares, etc.). In theses machines the manipulation and transmission of information can be described using the laws of classical physics. Since Newtonian mechanics is a special limit of quantum mechanics, computers making use of the laws of quantum mechanics have greater computational power than classical computers. This need to create a powerful computing machine is the driving motor for research in the field of quantum computing. Until today, there are a few different schemes for implementing a quantum computer based on the David Divincenzo chriterias. Among these are: Spectral hole burning, Trapped ion, e-Helium, Gated qubits, Nuclear Magnetic Resonance, Optics, Quantum dots, Neutral atom, superconductors and doped silicon. In this project only the quantum dot scheme will be discussed. In the year 1997 Daniel Loss and David P.DiVincenzo proposed a spin-qubit quantum computer also called The Loss-DiVincenzo quantum computer. This proposal is now considered to be one of the most promising candidates for quantum computation in the solid state. The main idea of the proposal was to use the intrinsic spin-1=2 degrees of freedom of individual elecrons confined in semiconductor quantum dots. The proposal was made in a way to satisfy the five requirements for quantum computing by David diVincenzo which will be described in sec.
    [Show full text]
  • Local and Distributed Quantum Computation
    Local and Distributed Quantum Computation Rodney Van Meter and Simon J. Devitt May 24, 2016 Abstract Experimental groups are now fabricating quantum processors powerful enough to execute small instances of quantum algorithms and definitively demonstrate quantum error correction that extends the lifetime of quantum data, adding ur- gency to architectural investigations. Although other options continue to be ex- plored, effort is coalescing around topological coding models as the most prac- tical implementation option for error correction on realizable microarchitectures. Scalability concerns have also motivated architects to propose distributed memory multicomputer architectures, with experimental efforts demonstrating some of the basic building blocks to make such designs possible. We compile the latest re- sults from a variety of different systems aiming at the construction of a scalable quantum computer. arXiv:1605.06951v1 [quant-ph] 23 May 2016 1 1 Introduction Quantum computers and networks look like increasingly inevitable extensions to our already astonishing classical computing and communication capabilities [1, 2]. How do they work, and once built, what capabilities will they bring? Quantum computation and communication can be understood through seven key con- cepts (see sidebar). Each concept is simple, but collectively they imply that our clas- sical notion of computation is incomplete, and that quantum effects can be used to efficiently solve some previously intractable problems. In the 1980s and 90s, a handful of algorithms were developed and the foundations of quantum computational complexity were laid, but the full range of capabilities and the process of creating new algorithms were poorly understood [1, 3, 4, 5, 6]. Over the last fifteen years, a deeper understanding of this process has developed, and the num- ber of proposed algorithms has exploded 1.
    [Show full text]
  • X 5 Quantum Computing with Semiconductor Quantum Dots
    X 5 Quantum Computing with Semiconductor Quantum Dots Carola Meyer Institut fur¨ Festkorperforschung¨ (IFF-9) Forschungszentrum Julich¨ GmbH Contents 1 Introduction 2 2 The ”Loss-DiVincenzo” proposal 2 3 Read-out of a single electron spin 3 3.1 Single shot read-out . 4 3.2 Singlet-Triplet read-out . 7 4 Manipulation of electron spins 8 4.1 Singlep spin rotation . 9 4.2 The SW AP operation . 10 5 Relaxation mechanisms 14 5.1 Spin-energy relaxation . 15 5.2 Dephasing and decoherence . 18 6 Summary and outlook 20 X5.2 Carola Meyer 1 Introduction Quantum dots can be used to confine single electrons as discussed by M. Wegewijs in the lecture ”Spin and Transport in Quantum Dots”. The quantum computing concepts based on quantum dots can be subdivided in two main branches: optical concepts and electrical concepts. In most of the optical concepts, the two level system representing the quantum bit (qubit) consists of exciton states. These are manipulated using polarized light. In electrical concepts, the spin states of electrons are used as qubit and manipulation can be done all-electrically. This contribution will concentrate on spin states of electrons for quantum information focusing on the most important electrical concept known as ”Loss-DiVincenzo proposal” [1]. It has been shown experimentally for this proposal that all of the ”DiVincenzo criteria” (for a general intro- duction into Quantum Computing see lecture ”Fundamental Concepts of Quantum Information Processing” by T. Schapers)¨ can be met as we shall see in the following. 2 The ”Loss-DiVincenzo” proposal A few years after the first implementation of the CNOT quantum gate using hyperfine and vibrational states of a 9Be+ ion in an ion trap as qubits [2], a row of proposals for a solid state quantum computer appeared, based on cooper pairs [3], nuclear spins in silicon [4], and last but not least electron spins in GaAs quantum dots [1].
    [Show full text]
  • Interface Between Topological and Superconducting Qubits
    University of Pennsylvania ScholarlyCommons Department of Physics Papers Department of Physics 3-28-2011 Interface Between Topological and Superconducting Qubits Liang Jiang California Institute of Technology Charles L. Kane University of Pennsylvania, [email protected] John Preskill California Institute of Technology Follow this and additional works at: https://repository.upenn.edu/physics_papers Part of the Physics Commons Recommended Citation Jiang, L., Kane, C. L., & Preskill, J. (2011). Interface Between Topological and Superconducting Qubits. Retrieved from https://repository.upenn.edu/physics_papers/129 Suggested Citation: Jiang, L., Kane, C.L. and Preskill, J. (2011). Interface between Topological and Superconducting Qubits. Physical Review Letters. 106, 130504. © 2011 The American Physical Society http://dx.doi.org/10.1103/PhysRevLett.106.130504 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/physics_papers/129 For more information, please contact [email protected]. Interface Between Topological and Superconducting Qubits Abstract We propose and analyze an interface between a topological qubit and a superconducting flux qubit. In our scheme, the interaction between Majorana fermions in a topological insulator is coherently controlled by a superconducting phase that depends on the quantum state of the flux qubit. A controlled-phase gate, achieved by pulsing this interaction on and off, can transfer quantum information between the topological qubit and the superconducting qubit. Disciplines
    [Show full text]
  • Pulse Sequences for Exchange-Based Quantum
    Prospects for Superconducting Qubits David DiVincenzo 24.01.2013 QIP Beijing Masters/PhD/postdocs available! http://www.physik.rwth-aachen.de/ institute/institut-fuer-quanteninformation/ (G: IQI Aachen) Prospects for Superconducting Qubits David DiVincenzo 24.01.2013 QIP Beijing Prospects for Superconducting Qubits Outline • Basic physics of Josephson devices • A short history of quantum effects in electric circuits • A Moore’s law for quantum coherence • Approaching fault tolerant fidelities (95%) • Scaling up with cavities – towards a surface code architecture • Will it work?? Interesting claim: Go direct from lumped electric circuit V To Schrodinger equation I Current controlled by f µ ò V dt Some other history: IBM had a large project (1975-85) to make a Josephson junction digital computer. “0” was the Current controlled by zero-voltage state, “1” was the finite-voltage state. f µ ò V dt Very different from a quantum computer. (Al or Nb) 2 1 (Al2O3) I Ic sin1 2 Coherent control of macroscopic quantum states in a single-Cooper-pair box Y. Nakamura, Yu. A. Pashkin and J. S. Tsai Nature 398, 786-788(29 April 1999) Feeble signs of quantum coherence Saclay Josephson junction qubit Science 296, 886 (2002) Oscillations show rotation of qubit at constant rate, with noise. s m Simple electric circuit… a l l harmonic oscillator with resonant frequency L C 0 1/ LC Quantum mechanically, like a kind of atom (with harmonic potential): x is any circuit variable (capacitor charge/current/voltage, Inductor flux/current/voltage) That is to say, it is a “macroscopic” variable that is being quantized.
    [Show full text]
  • In Accordance with the 'Partnerconvenant Qutech'
    2017 Annual Report In accordance with the ‘Partnerconvenant QuTech’ 1 Foreword Annual report 2017 QuTech On behalf of the whole of QuTech, In 2017, QuTech has attracted some of the I am proud to present the yearly best researchers in quantum technology to join report for 2017. It presents an over- our mission. Prof. Barbara Terhal (0,8 FTE) and view of the research ‘roadmaps’ part-time Prof. David DiVincenzo, both leading along with several other activities, experts in quantum information theory and error such as QuTech partnerships, correction, started at QuTech in September. outreach and academy. From our own ranks, Dr. Srijit Goswami has been contracted as a senior researcher on topological In my view, 2017 marks the completion of the first qubits. phase of QuTech, in which we have transitioned to a mission-driven research program, enabled With the internal research programs now running by both scientific breakthroughs and engineering at full steam, QuTech is ready for its next phase, efforts. Most PhD students that started their in which we will form stronger connections to research in the pre-QuTech era have now the outside world. The demonstrator projects graduated. The roadmaps of QuTech have a will allow external researchers to connect to and clear direction and demonstrate a strong synergy use our hardware and software platforms. The between science and engineering. The scientific establishment of a Microsoft research lab – foundation of QuTech is stronger than ever with, formally agreed upon in a joint signing ceremony for example, four publications making it into top in June 2017 - marks the start of a Quantum scientific journals Nature and Science in 2017, Campus in Delft.
    [Show full text]
  • Universality in Quantum Computation
    Universality in Quantum Computation David Deutsch, Adriano Barenco, and Artur Ekert Clarendon Laboratory, Department of Physics University of Oxford, Oxford, OX1 3PU, UK February 1, 2008 Abstract We show that in quantum computation almost every gate that operates on two or more bits is a universal gate. We discuss various physical considerations bearing on the proper definition of universality for computational components such as logic gates. To be published in Proc.R.Soc.London A, June 1995. Introduction It has been known for several years that the theory of quantum computers — i.e. machines that rely on characteristically quantum phenomena to perform computa- tions [1] — is substantially different from the classical theory of computation, which is essentially the theory of the universal Turing machine. We may identify three im- portant differences. Firstly, the properties of quantum computers are not postulated in abstracto but are deduced entirely from the laws of physics. Logically, this was arXiv:quant-ph/9505018v1 24 May 1995 already true of the classical theory, as Landauer [2] has pointed out, but the intuitive nature of the classically-available computational operations, and the millennia-long history of their study, allowed pioneers such as Turing, Church, Post and G¨odel to capture the correct classical theory by intuition alone, and falsely to assume that its foundations were self-evident or at least purely abstract. (There is an analogy here with geometry, another branch of physics that was formerly regarded as belonging to mathematics.) Secondly, quantum computers can perform certain classical tasks, such as factorisation [3], using quantum-mechanical algorithms [4] which have no classical analogues and can be overwhelmingly more efficient than any known classical algo- rithm.
    [Show full text]
  • REVIEWS of MODERN PHYSICS
    REVIEWS of MODERN PHYSICS A quarterly journal seeking to enhance communication among physicists by publishing comprehensive scholarly American Physical Society reviews of physics topics, as well as colloquia and tutorial articles in rapidly developing fields of physics. Officers President ROGER FALCONE Speaker of Council TIMOTHY GAY Editor: RANDALL KAMIEN, University of Pennsylvania Chief Executive Officer KATE P. KIRBY Colloquia Editor in Chief MICHAEL THOENNESSEN Editor: A. H. CASTRO NETO, National University of Singapore Publisher MATTHEW SALTER Chief Information Officer MARK D. DOYLE Chief Financial Officer MARGARET BANDERA Associate ASTROPHYSICS Deputy Executive Officer and Editors: FRIEDRICH-KARL THIELEMANN, Universitat¨ Basel Chief Operating Officer JAMES TAYLOR Chief Government Affairs ATOMIC, MOLECULAR, AND OPTICAL PHYSICS (Experimental) Officer FRANCIS SLAKEY KLAUS MØLMER, University of Aarhus One Physics Ellipse BIOLOGICAL PHYSICS College Park, MD 20740-3844 MARGARET S. CHEUNG, University of Houston; Center for Theoretical Biological Physics, Rice University CLIMATE SCIENCE APS Editorial Office WILLIAM D. COLLINS, University of California, Berkeley; Directors Lawrence Berkeley National Laboratory Editorial DANIEL T. KULP CONDENSED MATTER PHYSICS (Experimental) Journal Operations CHRISTINE M. GIACCONE ARTHUR F. HEBARD, University of Florida 1 Research Road CONDENSED MATTER PHYSICS (Theoretical) Ridge, NY 11961-2701 Phone: (631) 591-4000 DIETRICH BELITZ, University of Oregon Email: [email protected] ASTROPHYSICS Web: http://journals.aps.org/ VICKY KALOGERA, Northwestern University Submissions: [email protected] or MATHEMATICAL PHYSICS http://authors.aps.org/Submissions/ IGOR KLEBANOV, Princeton University NUCLEAR PHYSICS Member Subscriptions: WITOLD NAZAREWICZ, National Superconducting Cyclotron Laboratory, Michigan State University; Oak Ridge National Laboratory APS Membership Department One Physics Ellipse PARTICLE PHYSICS (Experimental) College Park, MD 20740-3844 PAUL D.
    [Show full text]
  • Part 1: Quantum Computation
    LA-UR-04-1778 A Quantum Information Science and Technology Roadmap Part 1: Quantum Computation Report of the Quantum Information Science and Technology Experts Panel “… it seems that the laws of physics present no barrier to reducing the size of computers until bits are the size of atoms, and quantum behavior holds sway.” Richard P. Feynman (1985) Disclaimer: The opinions expressed in this document are those of the Technology Experts Panel members and are subject to change. They should not to be taken to indicate in any way an official position of U.S. Government sponsors of this research. April 2, 2004 Version 2.0 This document is available electronically at: http://qist.lanl.gov Technology Experts Panel (TEP) Membership: Chair: Dr. Richard Hughes – Los Alamos National Laboratory Deputy Chair: Dr. Gary Doolen – Los Alamos National Laboratory Prof. David Awschalom – University of California: Santa Barbara Prof. Carlton Caves – University of New Mexico Prof. Michael Chapman – Georgia Tech Prof. Robert Clark – University of New South Wales Prof. David Cory – Massachusetts Institute of Technology Dr. David DiVincenzo – IBM: Thomas J. Watson Research Center Prof. Artur Ekert – Cambridge University Prof. P. Chris Hammel – Ohio State University Prof. Paul Kwiat – University of Illinois: Urbana-Champaign Prof. Seth Lloyd – Massachusetts Institute of Technology Prof. Gerard Milburn – University of Queensland Prof. Terry Orlando – Massachusetts Institute of Technology Prof. Duncan Steel – University of Michigan Prof. Umesh Vazirani – University of California: Berkeley Prof. K. Birgitta Whaley – University of California: Berkeley Dr. David Wineland – National Institute of Standards and Technology: Boulder Produced for the Advanced Research and Development Activity (ARDA) Document coordinator: Richard Hughes Editing & compositing: Todd Heinrichs This report was prepared as an account of work sponsored by an agency of the United States Government.
    [Show full text]