42 research outputs found

    Investigating the learning potential of the Second Quantum Revolution: development of an approach for secondary school students

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    In recent years we have witnessed important changes: the Second Quantum Revolution is in the spotlight of many countries, and it is creating a new generation of technologies. To unlock the potential of the Second Quantum Revolution, several countries have launched strategic plans and research programs that finance and set the pace of research and development of these new technologies (like the Quantum Flagship, the National Quantum Initiative Act and so on). The increasing pace of technological changes is also challenging science education and institutional systems, requiring them to help to prepare new generations of experts. This work is placed within physics education research and contributes to the challenge by developing an approach and a course about the Second Quantum Revolution. The aims are to promote quantum literacy and, in particular, to value from a cultural and educational perspective the Second Revolution. The dissertation is articulated in two parts. In the first, we unpack the Second Quantum Revolution from a cultural perspective and shed light on the main revolutionary aspects that are elevated to the rank of principles implemented in the design of a course for secondary school students, prospective and in-service teachers. The design process and the educational reconstruction of the activities are presented as well as the results of a pilot study conducted to investigate the impact of the approach on students' understanding and to gather feedback to refine and improve the instructional materials. The second part consists of the exploration of the Second Quantum Revolution as a context to introduce some basic concepts of quantum physics. We present the results of an implementation with secondary school students to investigate if and to what extent external representations could play any role to promote students’ understanding and acceptance of quantum physics as a personal reliable description of the world

    Integrality and cutting planes in semidefinite programming approaches for combinatorial optimization

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    Many real-life decision problems are discrete in nature. To solve such problems as mathematical optimization problems, integrality constraints are commonly incorporated in the model to reflect the choice of finitely many alternatives. At the same time, it is known that semidefinite programming is very suitable for obtaining strong relaxations of combinatorial optimization problems. In this dissertation, we study the interplay between semidefinite programming and integrality, where a special focus is put on the use of cutting-plane methods. Although the notions of integrality and cutting planes are well-studied in linear programming, integer semidefinite programs (ISDPs) are considered only recently. We show that manycombinatorial optimization problems can be modeled as ISDPs. Several theoretical concepts, such as the Chvátal-Gomory closure, total dual integrality and integer Lagrangian duality, are studied for the case of integer semidefinite programming. On the practical side, we introduce an improved branch-and-cut approach for ISDPs and a cutting-plane augmented Lagrangian method for solving semidefinite programs with a large number of cutting planes. Throughout the thesis, we apply our results to a wide range of combinatorial optimization problems, among which the quadratic cycle cover problem, the quadratic traveling salesman problem and the graph partition problem. Our approaches lead to novel, strong and efficient solution strategies for these problems, with the potential to be extended to other problem classes

    Jornadas Nacionales de InvestigaciĂłn en Ciberseguridad: actas de las VIII Jornadas Nacionales de InvestigaciĂłn en ciberseguridad: Vigo, 21 a 23 de junio de 2023

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    Jornadas Nacionales de InvestigaciĂłn en Ciberseguridad (8ÂŞ. 2023. Vigo)atlanTTicAMTEGA: Axencia para a modernizaciĂłn tecnolĂłxica de GaliciaINCIBE: Instituto Nacional de Cibersegurida

    MF-RALU: design of an efficient multi-functional reversible arithmetic and logic unit for processor design on field programmable gate array platform

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    Most modern computer applications use reversible logic gates to solve power dissipation issues. This manuscript uses an efficient multi-functional reversible arithmetic and logical unit (MF-RALU) to perform 30 operations. The 32-bit MF-RALU includes arithmetic, logical, complement, shifters, multiplexers, different adders, and multipliers. The multi-bit reversible multiplexers are used to construct the MF-RALU structure. The Reduced instruction set computer (RISC) processor is designed to realize the functionality of the MF-RALU. The MF-RALU can perform its operation in a single clock cycle. The 1-bit RALU is developed and compared with existing approaches with improvements in performance metrics. The 32-bit reversible arithmetic units (RAUs) and reversible logical units (RLUs) are constructed using 1-bit RALU. The MF-RALU and RISC processor are synthesized individually in the Vivado environment using Verilog-HDL and implemented on Artix-7 field programmable gate array (FPGA). The MF-RALU utilizes a <11% chip area and consumes 332 mW total power. The RISC processor utilizes a <3% chip area and works at 483 MHZ frequency by consuming 159 mW of total power on Artix-7 FPGA

    Testable Design for Positive Control Flipping Faults in Reversible Circuits

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    Fast computational power is a major concern in every computing system. The advancement of the fabrication process in the present semiconductor technologies provides to accommodate millions of gates per chip and is also capable of reducing the size of the chips. Concurrently, the complex circuit design always leads to high power dissipation and increases the fault rates. Due to these difficulties, researchers explore the reversible logic circuit as an alternative way to implement the low-power circuit design. It is also widely applied in recent technology trends like quantum computing. Analyzing the correct functional behavior of these circuits is an essential requirement in the testing of the circuit. This paper presents a testable design for the k-CNOT based circuit capable of diagnosing the Positive Control Flipping Faults (PCFFs) in reversible circuits. The proposed work shows that generating a single test vector that applies to the constructed design circuit is sufficient for covering the PCFFs in the reversible circuit. Further, the parity-bit operations are augmented to the constructed testable circuit that produces the parity-test pattern to extract the faulty gate location of PCFFs. Various reversible benchmark circuits are used for evaluating the experimental results to establish the correctness of the proposed fault diagnosis technique. Also a comparative analysis is performed with the existing work

    OpenQASM 3: a broader and deeper quantum assembly language

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    Quantum assembly languages are machine-independent languages that traditionally describe quantum computation in the circuit model. Open quantum assembly language (OpenQASM 2) was proposed as an imperative programming language for quantum circuits based on earlier QASM dialects. In principle, any quantum computation could be described using OpenQASM 2, but there is a need to describe a broader set of circuits beyond the language of qubits and gates. By examining interactive use cases, we recognize two different timescales of quantum-classical interactions: real-time classical computations that must be performed within the coherence times of the qubits, and near-time computations with less stringent timing. Since the near-time domain is adequately described by existing programming frameworks, we choose in OpenQASM 3 to focus on the real-time domain, which must be more tightly coupled to the execution of quantum operations. We add support for arbitrary control flow as well as calling external classical functions. In addition, we recognize the need to describe circuits at multiple levels of specificity, and therefore we extend the language to include timing, pulse control, and gate modifiers. These new language features create a multi-level intermediate representation for circuit development and optimization, as well as control sequence implementation for calibration, characterization, and error mitigation

    Understanding Quantum Technologies 2022

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    Understanding Quantum Technologies 2022 is a creative-commons ebook that provides a unique 360 degrees overview of quantum technologies from science and technology to geopolitical and societal issues. It covers quantum physics history, quantum physics 101, gate-based quantum computing, quantum computing engineering (including quantum error corrections and quantum computing energetics), quantum computing hardware (all qubit types, including quantum annealing and quantum simulation paradigms, history, science, research, implementation and vendors), quantum enabling technologies (cryogenics, control electronics, photonics, components fabs, raw materials), quantum computing algorithms, software development tools and use cases, unconventional computing (potential alternatives to quantum and classical computing), quantum telecommunications and cryptography, quantum sensing, quantum technologies around the world, quantum technologies societal impact and even quantum fake sciences. The main audience are computer science engineers, developers and IT specialists as well as quantum scientists and students who want to acquire a global view of how quantum technologies work, and particularly quantum computing. This version is an extensive update to the 2021 edition published in October 2021.Comment: 1132 pages, 920 figures, Letter forma

    Advancing classical simulators by measuring the magic of quantum computation

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    Stabiliser operations and state preparations are efficiently simulable by classical computers. Stabiliser circuits play a key role in quantum error correction and fault-tolerance, and can be promoted to universal quantum computation by the addition of "magic" resource states or non-Clifford gates. It is believed that classically simulating stabiliser circuits supplemented by magic must incur a performance overhead scaling exponentially with the amount of magic. Early simulation methods were limited to circuits with very few Clifford gates, but the need to simulate larger quantum circuits has motivated the development of new methods with reduced overhead. A common theme is that algorithm performance can often be linked to quantifiers of computational resource known as magic monotones. Previous methods have typically been restricted to specific types of circuit, such as unitary or gadgetised circuits. In this thesis we develop a framework for quantifying the resourcefulness of general qubit quantum circuits, and present improved classical simulation methods. We first introduce a family of magic state monotones that reveal a previously unknown formal connection between stabiliser rank and quasiprobability methods. We extend this family by presenting channel monotones that measure the magic of general qubit quantum operations. Next, we introduce a suite of classical algorithms for simulating quantum circuits, which improve on and extend previous methods. Each classical simulator has performance quantified by a related resource measure. We extend the stabiliser rank simulation method to admit mixed states and noisy operations, and refine a previously known sparsification method to yield improved performance. We present a generalisation of quasiprobability sampling techniques with significantly reduced exponential scaling. Finally, we evaluate the simulation cost per use for practically relevant quantum operations, and illustrate how to use our framework to realistically estimate resource costs for particular ideal or noisy quantum circuit instances

    Quantum computing on cloud-based processors

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    Thesis (MSc)--Stellenbosch University, 2022.ENGLISH ABSTRACT: The noisy intermediate-scale quantum (NISQ) era refers to the current technological epoch permeated with quantum processors that are big enough (50-100 qubits) to be no longer trivially simulatable with digital computers but not yet capable of full fault-tolerant computation. Such processors provide great testbeds to understand the practical issues and resources needed to realize quantum tasks in these processors, such as quantum algorithms. Many pressing issues arise in this context that are a direct consequence of the limitations of these processors (limited number of qubits, low qubit connectivity, and limited coherence times). Hence, for near-term quantum algorithms, there is an overriding imperative to adopt an approach that takes into account, and attempts to mitigate or circumvent some of these limitations. In this thesis, we examine realizing Grover’s quantum search algorithm for four qubits on IBM Q superconducting quantum processors, and potentially scaling up to more qubits. We also investigate non-canonical forms of the quantum search algorithm that trade accuracy for speed in a way that is more suitable for near-term processors. Our contribution to this topic of research is a slight improvement in the accuracy of the solution to a graph problem, solved with a quantum search algorithm implemented on IBM Q quantum processors by Satoh et .al in IEEE Transactions on Quantum Engineering (2020). We also explore the realization of a measurement-based quantum search algorithm for three qubits. Unfortunately, the number of qubits and two-qubit gates required by such an algorithm puts it beyond the reach of current quantum processors. Based on a recently published work with Professor Mark Tame, we also report a proof-of-concept demonstration of a quantum order-finding algorithm for factor- ing the integer 21. Our demonstration builds upon a previous demonstration by Martín-López et al. in Nature Photonics 6, 773 (2012). We go beyond this work by implementing the algorithm on IBM Q quantum processors using a configuration of approximate Toffoli gates with residual phase shifts, which preserves its functional correctness and allows us to achieve a complete factoring of N D 21 using a quantum circuit with relatively fewer two-qubit gates. Lastly, we realize a small-scale three-qubit quantum processor based on a spontaneous parametric down-conversion source built to generate a polarization-entangled Bell state. The state is enlarged by using the path degree of freedom of one of the photons to make a 3-qubit GHZ state. The generated state is versatile enough to carry out quantum correlation measurements such as Bell’s inequalities and entanglement witnesses. The entire experimental setup is motorized and made automatic allowing remote control of the measurements of each of the qubits, and we design and build a mobile graphical user interface to an provide intuitive and visual way to interact with the experiment.AFRIKAANSE OPSOMMING: Die ruiesende intermediêre skaal kwantum (NISQ) era verwys na die huidige tegnolo- giese epog deurdring met kwantumverwerkers wat groot genoeg is (50-100 qubits) om nie meer doeltreffend gesimuleer te kan word op digitale rekenaars nie, maar nog nie in staat is om volle foutverdraagsame berekening uit te voer nie. Sulke verwerkers bied baie goeie toetsplatforms om die probleme en hulpbronne mee te verstaan wat nodig is om kwantumtake soos kwantumalgoritmes in hierdie verwerkers te verwesenlik. Baie dringende kwessies ontstaan in hierdie konteks wat ’n direkte gevolg is van die beperkings van hierdie verwerkeers (beperkte aantal qubits, lae qubit konnektiwiteit en beperkte samehang tye). Daarom is daar vir naby-termyn kwantum algoritmes ’n oorheersende noodsaaklikheid om ’n benadering aan te neem wat hierdie beperkings in ag neem en pogings aanwend om sommige daarvan te versag of te omseil. In hierdie handeling het ons ondersoek ingestel na Grover se kwantumsoekalgoritmes vir vier qubits op IBM Q supergeleier kwantumverwerkers en die moontlike opskaal na ’n groter aantal qubits. Ons ondersoek ook nie-kanonieke vorms van die kwantum- soekalgoritmes wat akkuraatheid vir spoed verhandel op ’n manier wat meer geskik is vir naby-termyn verwerkers. Ons bydra tot hierdie navorsingsonderwerp is ’n effense verbetering aan die akkuraatheid van die oplossing vir ’n grafiekprobleem opgelos met ’n soekalgoritme wat op IBM Q kwantumverwerkers geïmplimenteer is deur Satoh et al. In IEEE Transactions on Quantum Engineering (2020). Ons ondersoek ook die verwesenliking van ’n waarneming-gebaseerde kwantumsoekalgoritme vir drie qubits. Die aantal qubits en twee-qubit logikahekke wat deur so ’n algoritme vereis word plaas dit buite die bereik van huidige kwantumverwerkers. Gebaseer op ’n onlangs-gepubliseerde navorsingsstuk saam met professor Mark Tame rapporteer ons ook ’n bewys-van-konsep demonstrasie van ’n kwantum volgordebepal- ing algoritme vir die faktorisering van die heelgetal 21. Ons demonstrasie bou voort op ’n vorige demonstrasie deur Martín López et al. In Nature Photonics 6,773 (2012). Ons brei uit op hierdie navorsing deur die die algoritme op IBM Q kwantumverwerk- ers te implimenteer met gebruik van benaderde Toffoli logikahekke met oorblywende faseverskuiwings – wat sy funksionele integriteit behou en ons instaat stel om ’n volledige faktoriseering van N = 21 te bereik met behulp van ’n kwantumstroombaan met ’n kleiner aantal twee-qubit logikahekke. Laastens bewerkstellig ons ’n kleinskaalse drie-qubit kwantumverwerker gebaseer op ’n spontane parametriese fluoressensie (“spontaneous parametric down-conversion”) bron wat gebou is om ’n polarisasie-verstrengelde Bell staat te genereer. Hierdie staat word vergroot deur die baanvryheidsgraad van een van die fotone te gebruik om kwantumkorrelasie metings soos Bell se ongelykhede en verstrengelingsgetuies uit te voer. Die hele eksperimentele opstelling word gemotoriseer en geautomatiseer sodat waarnemings van elk van die qubits deur middel van afstandbeheer gemaak kan word, en ons ontwerp en ontwikkel ’n mobile grafiese gebruikerskoppelvlak om ’n intuïtiewe en visuele manier te bied om met die eksperiment te kommunikeer.Master

    Law and Policy for the Quantum Age

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    Law and Policy for the Quantum Age is for readers interested in the political and business strategies underlying quantum sensing, computing, and communication. This work explains how these quantum technologies work, future national defense and legal landscapes for nations interested in strategic advantage, and paths to profit for companies
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