DOCSLIB.ORG

Brief Primer on the Fundaments of Quantum Computing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Brief Primer on the Fundaments of Quantum Computing Brief Primer on the Fundaments of Quantum Computing Richard L Amoroso [email protected] Abstract . 4 Preface . 4 PART 1 From Concept to Conundrum 1.1 Preamble – Bits, Qubits and Complex Space . 8 1.2 Panoply of QC Architectures and Substrates – Limited Overview . .9 1.2.1 Quantum Turing Machine . .10 1.2.2 Quantum Circuit Computing Model . 10 1.2.3 Measurement Based Quantum Computing . .11 1.2.4 Adiabatic Quantum Computer . .12 1.2.5 The Kane Nuclear Spin QC . 13 1.2.6 QRAM Models of Quantum Computation . 14 1.2.7 Electrons-On-Helium Quantum Computers . 14 1.2.8 Fullerene-Based ESR Quantum Computer . 15 1.2.9 Superconductor-Based Quantum Computers . 16 1.2.9.1 SQUID-BASED SUPERCONDUCTOR QC . 16 1.2.9.2 TRAPPED ION-BASED SUPERCONDUCTOR QC . 17 1.2.10 Diamond Based Quantum Computers . 18 1.2.11 Quantum Dot Quantum Computer . 19 1.2.12 Transistor-Based Quantum Computer . .20 1.2.13 Molecular Magnet Quantum Computer . .21 1.2.14 Bose–Einstein Condensate-Based Quantum Computer . .22 1.2.15 Rare-Earth-Metal-Ion-Doped Inorganic Crystal QC . 22 1.2.16 Linear Optical Quantum Computer (LOQC) . .23 1.2.17 Optical Lattice Based Quantum Computing (OLQC) . 24 1.2.18 Cavity Quantum Electrodynamics Quantum Computing. 25 1.2.19 Nuclear Magnetic Resonance (NMR) Quantum Computing. 26 Richard L Amoroso – Fundaments of Quantum Computing 1.2.19.1 LIQUID-STATE NMRQC . 26 1.2.19.2 SOLID-STATE NMRQC. 27 1.2.20 Topological Quantum Computing (TQC) . 28 1.2.21 Unified Field Mechanical Quantum Computing . 29 1.3 Concept. .29 1.4. Conundrum - Hypotheses non Fingo. 30 1.4.1 The Church-Turing Hypothesis . .30 1.4.2 The Church-Turing-Deutsch Thesis. .31 1.4.3 Perspicacious Perspicacity – Who Has it? Where can I get Some? . .31 References. .. .32 PART 2 Cornucopia of Quantum Logic Gates 2.1 Fundamental Properties of Gate Operations. .35 2.2 Unitary Operators as Quantum Gates. .36 2.3 Some Fundamental Quantum Gates . .37 2.5 Rotation Gate Quantum Multiplexer. 43 References. .. .44 PART 3 Surmounting Uncertainty Supervening Decoherence 3.1 Phenomenology Versus Ontology . 45 3.2 The Turing Paradox and Quantum Zeno Effect . 50 3.3 From the Perspective of Multiverse Cosmology. 51 3.4 Micromagnetics LSXD Topological Charge Brane Conformation. 54 3.5 Catastrophe Theory and the M-Theoretic Formalism. .59 3.6 Protocol for Empirically Testing Unified Theoretic Cosmology. .63 3.7 Introduction to a P 1 Experimental Design. 65 3.8 Conclusions . .. .72 References . .. 73 PART 4 Measurement With Certainty 4.1 Introduction – Summary of Purpose. .. .77 4.2 The Principle of Superposition. .. .79 4.3 Oscillatory Rabi NMR Resonance Cycles . 80 4.4 The Problem of Decoherence . .81 2 Richard L Amoroso – Fundaments of Quantum Computing 4.5 Insight into the Measurement Problem . 82 4.6 New Physics from Anthropic Cosmology. 84 4.6.1 Spacetime Exciplex - UF Noeon Mediator. .86 4.6.2 Quantum Phenomenology Versus Noetic UFM Field Ontology . 87 4.7 The Basement of Reality - Through the Glass Ceiling . .89 4.8 Empirical Tests of UFM Cosmology Summarized . 91 4.8.1 Summary of Experimental Protocols . .92 4.8.2 Review of Key Experimental Details. 93 4.9 Unified Field Mechanical (UFM) Précis - Required Parameters. 96 4.10 Formalizing the Noeon, New Physical Unit Quantifying UFM Energy . 97 4.11 Quarkonium Flag Manifold Topology. .99 4.12 Singularities, Unitary Operators and Domains of Action . .100 4.12.1 Semi-Classical Limit . 101 4.12.2 Semi-Quantum Limit . 101 4.13 Measurement . 101 4.14 The No-Cloning Theorem (NCT) . .103 4.14.1 Proof of the Quantum No-Cloning Theorem (NCT) . .104 4.14.2 Quantum No-Deleting Theorem. .105 4.15 The Tight-Bound State Protocol . 105 4.16 Indicia of the UFM Tight Bound State CQED Model. .106 4.17 Building the UFM TBS Experimental Protocol . .108 4.18 Issues of Experimental Design . 117 References. .. 120 PART 5 New Classes of Quantum Algorithms 5.1 Introduction - From al-Khwarizmi to Unified Field-Gorhythms . .125 5.2 The Church-Turing Hypothesis . .126 5.3 Algorithms Based on the Quantum Fourier Transform . .126 5.4 Exponential Speedup by Quantum Information Processing . .127 5.5 Classical Holographic Reduction Algorithms . 129 5.6 Ontological-Phase UFM Holographic Algorithms .. 130 5.7 The Superimplicate Order and Instantaneous UQC Algorithms .. 132 5.8 Some Ontological-Phase Geometric Topology. 135 5.9 Summation. .138 References . .139 3 Richard L Amoroso – Fundaments of Quantum Computing This QC primer is based on excerpts from the breakthrough volume Universal Quantum Computing (ISBN: 978-981-3145-99-3) which touts having dissolved the remaining barriers to implementing Bulk Universal Quantum Computing (UQC), and as such most likely describes the most advanced QC development platform. Numerous books, hundreds of patents, thousands of papers and a Googolplex of considerations fill the pantheon of QC R&D. Of late QC mathemagicians claim QCs already exist; but by what chimeric definition. Does flipping a few qubits in a logic gate without an algorithm qualify as quantum computing? In physics, theory bears little weight without rigorous experimental confirmation, less if new, radical or a paradigm shift. This volume develops quantum computing based on '3rd regime' physics of Unified Field Mechanics (UFM). What distinguishes this work from a myriad of other avenues to UQC under study? Virtually all R&D paths struggle with technology and decoherence. If the currently highly favored room-sized cryogenically cooled quantum Hall anyon bilayer graphene QCs ever become successful, they would be reminiscent of the city block-sized Eniac computer of 1946. In 2017 quantum Hall techniques experimentally discovered additional dimension, said to be inaccessible and were called ‘artificial’. This scenario will not last long; the floodgates will open momentarily. Then we will have actual QCs! The QC prototype proposed herein is room temperature and tabletop. It is dramatically different in that it is not confined to the limitations of quantum mechanics; since it is based on principles of UFM, the Uncertainty Principle and Decoherence no longer apply. Thus, this QC model could be implemented on any other quantum platform! Preface – From the Volume The breakthrough volume, from which the following excerpts come - (ISBN: 978-981-3145-99-3 print; ISBN: 978-981-3146-01-3 electronic) touts having conceptually dissolved the remaining barriers for immediate implementation of Bulk Universal Quantum Computing (UQC), and as such most likely describes the most advanced basis for developing Quantum Information Processing (QIP). Numerous books, many 100s of patents, 1,000s of papers and a Googolplex of considerations fill the pantheon of QC R&D. Of late QC mathemagicians claim QCs already exist; but by what chimeric definition. Does flipping a few qubits in a logic gate qualify as quantum computing? In physics, theory bears little weight until it is supported by rigorous experimental confirmation, less if new, radical or an untested paradigm shift. This volume develops quantum computing based on ‘3rd regime’ physics of Unified Field Mechanics (UFM). What distinguishes this work from myriad other avenues to UQC under study? Virtually all R&D paths struggle with refining technology and decoherence. If the highly favored room-sized cryogenically cooled QCs ever become successful, they would be reminiscent of the 1946 city block-sized Eniac computer that contained 17,468 vacuum tubes. Does the proposed by-pass of that step retard acceptance of the UFM model; maybe, maybe not as UFM modeling also puts an end to the need for large supercolliders like the CERN LHC. The QC prototype proposed herein is room temperature, tabletop, surmounts uncertainty and supervenes decoherence during.
Load more

Recommended publications
  • Engineering the Quantum Foam
    Engineering the Quantum Foam Reginald T. Cahill School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide 5001, Australia [email protected] _____________________________________________________ ABSTRACT In 1990 Alcubierre, within the General Relativity model for space-time, proposed a scenario for ‘warp drive’ faster than light travel, in which objects would achieve such speeds by actually being stationary within a bubble of space which itself was moving through space, the idea being that the speed of the bubble was not itself limited by the speed of light. However that scenario required exotic matter to stabilise the boundary of the bubble. Here that proposal is re-examined within the context of the new modelling of space in which space is a quantum system, viz a quantum foam, with on-going classicalisation. This model has lead to the resolution of a number of longstanding problems, including a dynamical explanation for the so-called `dark matter’ effect. It has also given the first evidence of quantum gravity effects, as experimental data has shown that a new dimensionless constant characterising the self-interaction of space is the fine structure constant. The studies here begin the task of examining to what extent the new spatial self-interaction dynamics can play a role in stabilising the boundary without exotic matter, and whether the boundary stabilisation dynamics can be engineered; this would amount to quantum gravity engineering. 1 Introduction The modelling of space within physics has been an enormously challenging task dating back in the modern era to Galileo, mainly because it has proven very difficult, both conceptually and experimentally, to get a ‘handle’ on the phenomenon of space.
    [Show full text]
  • Quantum Dots
    NMR Silicon quantum computing Quantum dots Practical realization of Quantum Computation QC implementation proposals Bulk spin Optical Atoms Solid state Resonance (NMR) Linear optics Cavity QED Trapped ions Optical lattices Electrons on He Semiconductors Superconductors Nuclear spin Electron spin Orbital state Flux Charge qubits qubits qubits qubits qubits http://courses.washington.edu/bbbteach/576/ 1 What is NMR (Nuclear magnetic resonance) ? NMR: study of the transitions between the Zeeman levels of an atomic nucleus in a magnetic field. • If put a system of nuclei with non-zero spin in E static magnetic field, there 2 E will be different energy RF 0 levels. 0 E2 E1 • If radio frequency wave with is applied, RF 0 E1 transitions will occur. Nuclear Energy Levels 2 Nuclear magnetic resonance NMR is one of the most important spectroscopic techniques available in molecular sciences since the frequencies of the NMR signal allow study of molecular structure. Basic idea: use nuclear spins of molecules as qubits Liquid NMR: rapid molecular motion in fluids greatly simplifies the NMR Hamiltonian as anisotropic interactions can be replaced by their isotropic averages, often zero. The signals are often narrow (high-resolution NMR). It is impossible to pick individual molecule. The combined signal from all molecules is detected (“bulk” NMR). Liquid Solution NMR Billions of molecules are used, each one a separate quantum computer. Most advanced experimental demonstrations to date, but poor scalability as molecule design gets difficult. Qubits are stored in nuclear spin of molecules and controlled by different frequencies of magnetic pulses. Vandersypen, 2000 Used to factor 15 experimentally.
    [Show full text]
  • A Radix-4 Chrestenson Gate for Optical Quantum Computation
    A Radix-4 Chrestenson Gate for Optical Quantum Computation Kaitlin N. Smith, Tim P. LaFave Jr., Duncan L. MacFarlane, and Mitchell A. Thornton Quantum Informatics Research Group Southern Methodist University Dallas, TX, USA fknsmith, tlafave, dmacfarlane, mitchg @smu.edu Abstract—A recently developed four-port directional coupler is described in Section III followed by the realization of the used in optical signal processing applications is shown to be coupler with optical elements including its fabrication and equivalent to a radix-4 Chrestenson operator, or gate, in quantum characterization in Section IV. Demonstration of the four-port information processing (QIP) applications. The radix-4 qudit is implemented as a location-encoded photon incident on one of coupler as a radix-4 Chrestenson gate is presented in Section V the four ports of the coupler. The quantum informatics transfer and a summary with conclusions is found in Section VI. matrix is derived for the device based upon the conservation of energy equations when the coupler is employed in a classical II. QUANTUM THEORY BACKGROUND sense in an optical communications environment. The resulting transfer matrix is the radix-4 Chrestenson transform. This result A. The Qubit vs. Qudit indicates that a new practical device is available for use in the The quantum bit, or qubit, is the standard unit of information implementation of radix-4 QIP applications or in the construction for radix-2, or base-2, quantum computing. The qubit models of a radix-4 quantum computer. Index Terms—quantum information processing; quantum pho- information as a linear combination of two orthonormal basis tonics; qudit; states such as the states j0i and j1i.
    [Show full text]
  • Electrical Characterisation of Ion Implantation Induced Defects in Silicon Based Devices for Quantum Applications
    Electrical Characterisation of Ion Implantation Induced Defects in Silicon Based Devices for Quantum Applications Aochen Duan Supervised by Professor Jeffrey C. McCallum and Doctor Brett C. Johnson School of Physics The University of Melbourne Australia 1 Abstract Quantum devices that leverage the manufacturing techniques of silicon-based classical computers make them strong candidates for future quantum computers. However, the demands on device quality are much more stringent given that quantum states can de- cohere via interactions with their environment. In this thesis, a detailed investigation of ion implantation induced defects generated during device fabrication in a regime relevant to quantum device fabrication is presented. We identify different types of defects in Si using various advanced electrical characterisation techniques. The first experimental technique, electrical conductance, was used for the investigation of the interface state density of both n- and p-type MOS capacitors after ion implantation of various species followed by a rapid thermal anneal. As precise atomic placement is critical for building Si based quantum computers, implantation through the oxide in fully fabricated devices is necessary for some applications. However, implanting through the oxide might affect the quality of the Si/SiO2 interface which is in close proximity to the region in which manipulation of the qubits take place. Implanting ions in MOS capacitors through the oxide is a model for the damage that might be observed in other fabricated devices. It will be shown that the interface state density only changes significantly after a fluence of 1013 ions/cm2 except for Bi in p-type silicon, where significant increase in interface state density was observed after a fluence of 1011 Bi/cm2.
    [Show full text]
  • Technology-Dependent Quantum Logic Synthesis and Compilation
    Southern Methodist University SMU Scholar Electrical Engineering Theses and Dissertations Electrical Engineering Fall 12-21-2019 Technology-dependent Quantum Logic Synthesis and Compilation Kaitlin Smith Southern Methodist University, [email protected] Follow this and additional works at: https://scholar.smu.edu/engineering_electrical_etds Part of the Other Electrical and Computer Engineering Commons Recommended Citation Smith, Kaitlin, "Technology-dependent Quantum Logic Synthesis and Compilation" (2019). Electrical Engineering Theses and Dissertations. 30. https://scholar.smu.edu/engineering_electrical_etds/30 This Dissertation is brought to you for free and open access by the Electrical Engineering at SMU Scholar. It has been accepted for inclusion in Electrical Engineering Theses and Dissertations by an authorized administrator of SMU Scholar. For more information, please visit http://digitalrepository.smu.edu. TECHNOLOGY-DEPENDENT QUANTUM LOGIC SYNTHESIS AND COMPILATION Approved by: Dr. Mitchell Thornton - Committee Chairman Dr. Jennifer Dworak Dr. Gary Evans Dr. Duncan MacFarlane Dr. Theodore Manikas Dr. Ronald Rohrer TECHNOLOGY-DEPENDENT QUANTUM LOGIC SYNTHESIS AND COMPILATION A Dissertation Presented to the Graduate Faculty of the Lyle School of Engineering Southern Methodist University in Partial Fulfillment of the Requirements for the degree of Doctor of Philosophy with a Major in Electrical Engineering by Kaitlin N. Smith (B.S., EE, Southern Methodist University, 2014) (B.S., Mathematics, Southern Methodist University, 2014) (M.S., EE, Southern Methodist University, 2015) December 21, 2019 ACKNOWLEDGMENTS I am grateful for the many people in my life who made the completion of this dissertation possible. First, I would like to thank Dr. Mitch Thornton for introducing me to the field of quantum computation and for directing me during my graduate studies.
    [Show full text]
  • Arxiv:Quant-Ph/0512071 V1 9 Dec 2005 Contents I.Ipoeet Ntekmprotocol KLM the on Improvements III
    Linear optical quantum computing Pieter Kok,1,2, ∗ W.J. Munro,2 Kae Nemoto,3 T.C. Ralph,4 Jonathan P. Dowling,5,6 and G.J. Milburn4 1Department of Materials, Oxford University, Oxford OX1 3PH, UK 2Hewlett-Packard Laboratories, Filton Road Stoke Gifford, Bristol BS34 8QZ, UK 3National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan 4Centre for Quantum Computer Technology, University of Queensland, St. Lucia, Queensland 4072, Australia 5Hearne Institute for Theoretical Physics, Dept. of Physics and Astronomy, LSU, Baton Rouge, Louisiana 6Institute for Quantum Studies, Department of Physics, Texas A&M University (Dated: December 9, 2005) Linear optics with photo-detection is a prominent candidate for practical quantum computing. The protocol by Knill, Laflamme and Milburn [Nature 409, 46 (2001)] explicitly demonstrates that efficient scalable quantum computing with single photons, linear optical elements, and projec- tive measurements is possible. Subsequently, several improvements on this protocol have started to bridge the gap between theoretical scalability and practical implementation. We review the original proposal and its improvements, and we give a few examples of experimental two-qubit gates. We discuss the use of realistic components, the errors they induce in the computation, and how they can be corrected. PACS numbers: 03.67.Hk, 03.65.Ta, 03.65.Ud Contents References 36 I. Quantum computing with light 1 A. Linear quantum optics 2 B. N-port interferometers and optical circuits 3 C. Qubits in linear optics 4 I. QUANTUM COMPUTING WITH LIGHT D. Early optical quantum computers and nonlinearities 5 Quantum computing has attracted much attention over II.
    [Show full text]
  • Arxiv:1903.12615V1
    Encoding an oscillator into many oscillators Kyungjoo Noh,1, 2, ∗ S. M. Girvin,1, 2 and Liang Jiang1, 2, y 1Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520, USA 2Yale Quantum Institute, Yale University, New Haven, Connecticut 06520, USA Gaussian errors such as excitation losses, thermal noise and additive Gaussian noise errors are key challenges in realizing large-scale fault-tolerant continuous-variable (CV) quantum information processing and therefore bosonic quantum error correction (QEC) is essential. In many bosonic QEC schemes proposed so far, a finite dimensional discrete-variable (DV) quantum system is encoded into noisy CV systems. In this case, the bosonic nature of the physical CV systems is lost at the error-corrected logical level. On the other hand, there are several proposals for encoding an infinite dimensional CV system into noisy CV systems. However, these CV-into-CV encoding schemes are in the class of Gaussian quantum error correction and therefore cannot correct practically relevant Gaussian errors due to established no-go theorems which state that Gaussian errors cannot be corrected by Gaussian QEC schemes. Here, we work around these no-go results and show that it is possible to correct Gaussian errors using GKP states as non-Gaussian resources. In particular, we propose a family of non-Gaussian quantum error-correcting codes, GKP-repetition codes, and demonstrate that they can correct additive Gaussian noise errors. In addition, we generalize our GKP-repetition codes to an even broader class of non-Gaussian QEC codes, namely, GKP-stabilizer codes and show that there exists a highly hardware-efficient GKP-stabilizer code, the two-mode GKP-squeezed-repetition code, that can quadratically suppress additive Gaussian noise errors in both the position and momentum quadratures.
    [Show full text]
  • G53NSC and G54NSC Non Standard Computation Research Presentations
    G53NSC and G54NSC Non Standard Computation Research Presentations March the 23rd and 30th, 2010 Tuesday the 23rd of March, 2010 11:00 - James Barratt • Quantum error correction 11:30 - Adam Christopher Dunkley and Domanic Nathan Curtis Smith- • Jones One-Way quantum computation and the Measurement calculus 12:00 - Jack Ewing and Dean Bowler • Physical realisations of quantum computers Tuesday the 30th of March, 2010 11:00 - Jiri Kremser and Ondrej Bozek Quantum cellular automaton • 11:30 - Andrew Paul Sharkey and Richard Stokes Entropy and Infor- • mation 12:00 - Daniel Nicholas Kiss Quantum cryptography • 1 QUANTUM ERROR CORRECTION JAMES BARRATT Abstract. Quantum error correction is currently considered to be an extremely impor- tant area of quantum computing as any physically realisable quantum computer will need to contend with the issues of decoherence and other quantum noise. A number of tech- niques have been developed that provide some protection against these problems, which will be discussed. 1. Introduction It has been realised that the quantum mechanical behaviour of matter at the atomic and subatomic scale may be used to speed up certain computations. This is mainly due to the fact that according to the laws of quantum mechanics particles can exist in a superposition of classical states. A single bit of information can be modelled in a number of ways by particles at this scale. This leads to the notion of a qubit (quantum bit), which is the quantum analogue of a classical bit, that can exist in the states 0, 1 or a superposition of the two. A number of quantum algorithms have been invented that provide considerable improvement on their best known classical counterparts, providing the impetus to build a quantum computer.
    [Show full text]
  • Does LIGO Prove General Relativity?
    Does LIGO Prove General Relativity? by Clark M. Thomas © May 12, 2016; modified Sept. 11, 2016 ABSTRACT LIGO-detected "gravitational waves" are very real. This successful experiment in early 2016 did open up a new form of astronomy. Despite the hype, the initial explanation for what was discovered neither confirms nor denies Einstein's full theory of General Relativity, including the concept of gravity membranes (branes). The LIGO discovery can be explained by a model somewhat similar to de Broglie-Bohm quantum pilot waves. LIGO-detected "gravitational waves" are real. The successful experiment in early 2016 did open up a new form of astronomy. However, despite the hype, the initial explanation for what was discovered neither confirms nor denies Einstein's full theory of Page !1 of !11 General Relativity, including the concept of gravity membranes (branes). It merely confirms his 2016 guess that gravity waves should be generated, and that they potentially could be detected and measured. That’s a long way from the core of his GR thesis.1 “Spacetime” is a cool idea, but it merely records the timely effects of motion within a 3D Universe, making up frame-specific 4D spacetimes – with seemingly infinite discrete inertial frames of reference.2 Einstein's idea of "c" being the somewhat mystical absolute limit of measured speed in any direction simply acknowledges the initial acceleration of electromagnetic particle strings from their graviton base within a frame of reference. Speed of light within a vacuum is only the initial burst of acceleration for each yin/yang photon string as it leaves its graviton “mother ship.”3 A better explanation for the waves detected by LIGO is a 21st century paradigm of push/shadow gravity – within a 3D set sea of “quantum foam” (primarily Yin/Yang particles, Y/Y strings, Y/Y graviton rings, and some larger particles).
    [Show full text]
  • Quantum Geometrodynamics with Intrinsic Time Development
    2nd LeCosPA International Symposium, Nat.Taiwan U. (December 17th 2015) Quantum geometrodynamics with intrinsic time development 許 Chopin Soo 祖 斌 Department of Physics, Nat. Cheng Kung U, Taiwan Everything? What about (let’s not forget) the `problem of time’ ? A very wise man once said “What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know”, pondering the mystery of what time really is, Saint Augustine (of Hippo) (354-430 A.D.) wrote in his Confessions《懺悔錄》, “Si nemo ex me quaerat scio; Si quaerente explicare velim, nescio ’’ Time: We all have some intuitive understanding of time. But what is time? Where does it comes from? Physical theory of space and time Einstein’s GR: Classical space-time <-> (pseudo-Riemannian)Geometry Quantum Gravity: “`Spacetime’ - a concept of limited applicability” ---J. A. Wheeler What, if anything at all, plays the role of “time” in Quantum Gravity? Importance of time: 1)Quantum probabilities are normalized at fixed instances of time 2)Time <-> Hamiltonian as generator of time translation/evolution Hamiltonian <-> Energy Time: Is it 1) fundamental (present even in Quantum Gravity)? 2) emergent (present in the (semi)-classical context only)? 3) an illusion (!)? … Nemeti, Istvan et al. arXiv:0811.2910 [gr-qc] Getting to know Einstein’s theory Spacetime tells matter how to move; matter tells spacetime how to curve John Wheeler, in Geons, Black Holes, and Quantum Foam p.235 This saying has seeped into popular culture and public discourse; but with all due respect to Wheeler, it is the Hamiltonian which tells everything (including the metric) how to move! from The Early Universe (E.
    [Show full text]
  • Quantum Information Hidden in Quantum Fields
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 21 July 2020 Peer-reviewed version available at Quantum Reports 2020, 2, 33; doi:10.3390/quantum2030033 Article Quantum Information Hidden in Quantum Fields Paola Zizzi Department of Brain and Behavioural Sciences, University of Pavia, Piazza Botta, 11, 27100 Pavia, Italy; [email protected]; Phone: +39 3475300467 Abstract: We investigate a possible reduction mechanism from (bosonic) Quantum Field Theory (QFT) to Quantum Mechanics (QM), in a way that could explain the apparent loss of degrees of freedom of the original theory in terms of quantum information in the reduced one. This reduction mechanism consists mainly in performing an ansatz on the boson field operator, which takes into account quantum foam and non-commutative geometry. Through the reduction mechanism, QFT reveals its hidden internal structure, which is a quantum network of maximally entangled multipartite states. In the end, a new approach to the quantum simulation of QFT is proposed through the use of QFT's internal quantum network Keywords: Quantum field theory; Quantum information; Quantum foam; Non-commutative geometry; Quantum simulation 1. Introduction Until the 1950s, the common opinion was that quantum field theory (QFT) was just quantum mechanics (QM) plus special relativity. But that is not the whole story, as well described in [1] [2]. There, the authors mainly say that the fact that QFT was "discovered" in an attempt to extend QM to the relativistic regime is only historically accidental. Indeed, QFT is necessary and applied also in the study of condensed matter, e.g. in the case of superconductivity, superfluidity, ferromagnetism, etc.
    [Show full text]
  • High Fidelity Readout of Trapped Ion Qubits
    High Fidelity Readout of Trapped Ion Qubits A thesis submitted for the degree of Doctor of Philosophy Alice Heather Burrell Trinity Term Exeter College 2010 Oxford ii Abstract High Fidelity Readout of Trapped Ion Qubits A thesis submitted for the degree of Doctor of Philosophy, Trinity Term 2010 Alice Heather Burrell Exeter College, Oxford This thesis describes experimental demonstrations of high-fidelity readout of trapped ion quantum bits (“qubits”) for quantum information processing. We present direct single-shot measurement of an “optical” qubit stored in a single 40Ca+ ion by the process of resonance fluorescence with a fidelity of 99.991(1)% (sur- passing the level necessary for fault-tolerant quantum computation). A time-resolved maximum likelihood method is used to discriminate efficiently between the two qubit states based on photon-counting information, even in the presence of qubit decay from one state to the other. It also screens out errors due to cosmic ray events in the detec- tor, a phenomenon investigated in this work. An adaptive method allows the 99.99% level to be reached in 145 µs average detection time. The readout fidelity is asymmetric: 99.9998% is possible for the “bright” qubit state, while retaining 99.98% for the “dark” state. This asymmetry could be exploited in quantum error correction (by encoding the “no-error” syndrome of the ancilla qubits in the “bright” state), as could the likelihood values computed (which quantify confidence in the measurement outcome). We then extend the work to parallel readout of a four-ion string using a CCD camera and achieve the same 99.99% net fidelity, limited by qubit decay in the 400 µs exposure time.
    [Show full text]