Quantum Computing Trends
Quantum Computing TrendsYuri AlexeevComputational Science DivisionArgonne National Laboratoryand University of Chicago
What is Quantum Information Science? Quantum mechanics explains how world works at microscopic level, whichgoverns behavior of all physical systems, regardless of their size. Arguablyone of the greatest scientific discoveries on 20th century, leading tofundamental discoveries of how nature works Information science revolutionized how information is collected, stored,analyzed, manipulated, protected, and moved. It ushered new age ofinformation in 20th century, with major repercussions in economic, social,and political spheres We see convergence of two 20th century greatest revolutions in the form ofQuantum Information Science (QIS)Credit: NIST2
Quantum Information Science QIS exploits unique quantum effects such as superposition,interference, and entanglement to obtain, compute, and transmitinformation in the ways that are superior compared to classicaltechnology (digital, Newtonian) The key concept is entanglement (“spooky action at a distance”, EPRpair ). Works only for only very small object (electrons, photons, atomsetc). It is proven to be essential to achieve “quantum advantage” or for“quantum teleportation”ClassicalQuantumOutcome ProbabilityOutcome Probability001/4001/2011/4010101/4100111/4111/23
Key Concepts Qubit - basic unit of quantum information, which is the quantum versionof the classical binary bit. It can exist in superposition – any state between0 and 1 Qubit fidelity – how long qubit stays coherent/operational Quantum effects - superposition, interference, and entanglement NISQ - Noisy Intermediate-Scale Quantum technology, often refers in thecontext of modern very noisy quantum computers QASM - Quantum Assembly used for programming quantum computers Quantum supremacy - demonstration of that a programmable quantumdevice can solve a problem (any problem) that no classical computer cansolve in any feasible amount of time Quantum advantage - same as supremacy, but for useful applications4
Quantum Supremacy DemonstrationGoogle Sycamore processor (53 qubit device) takes about 200 seconds to sample oneinstance of a quantum circuit a million times. The equivalent task on Summit wouldtake approximately 10,000 years. It is 1.6B times faster.5
Quantum ApplicationsCredit: NIST6
Quantum Applications Secure telecommunication (near future): quantum key distributionis an ultra-secure communication method that requires a key todecipher a message. If the message gets intercepted, no one elsecan read it. Quantum sensors (not far future): devices that exploits quantumentanglement to achieve a sensitivity or resolution that is betterthan can be achieved using only classical systems. Applications:astrophysics, high energy physics, military (quantum radars) etc. Scientific problems (far future): a number of NP-hard combinatorialproblems can be solved efficiently on quantum computers (i.e.linear algebra and database search). Applications: quantumchemistry, traffic control, real-time risk analysis, financial, andforecasting etc.7
Quantum Teleportation Chinese scientists set the record for the farthest quantum teleportation in2017. It demonstrated that quantum teleportation works over distance of870 miles. It paves the way to quantum internet Quantum-encrypted images by encoding them as strings of numbersbased on the quantum states of photons and sent them across distancesof up to 4,722 miles between Beijing and Vienna in 2018 The best way to distribute quantum entanglement around the globe is viaa massive constellation of orbiting satellites according to just publishedMIT report UChicago – Argonne – Fermilab30 mile quantum networkis under construction8
U.S. Quantum InternetDOE Unveiled blueprint for a U.S. Quantum Internet July 24, 2020.The initial plan is to connect up all 17 of their national labs to establish the backboneof the quantum internet. The ultimate goal is to build a multi-institutional ecosystembetween laboratories, academia, and industry to transition from demonstration tooperational infrastructure.9
Publicly Announced National and InternationalInitiatives in QISNationInitiativeYearLaunchedInvestment,Time frameScopeUSUS QuantumInitiative2020Up to 625 over5 yearsNational centers of QIS excellence (upto five centers for up to 25M/year)ChinaNationalLaboratory for QIS2018 11.4BCentralized quantum research facilityEUQuantumTechnologiesFlagship2018 1.1B over 10yearsQuantum communication, metrologyand sensing, simulation, computing,and fundamental scienceRussiaRussian QuantumInitiative2019 780MQuantum computers, quantumcomputing, quantum communication,quantum sensorsGermanyGerman QuantumImitative2019 712MQuantum computers, quantumcomputing, quantum communication,quantum sensorsUKUK NationalQuantumTechnologiesProgram2014 358M over 5yearsSensors and metrology, quantumenhanced imaging, quantumcommunications technologies10
Hardware timelineCredit: MIT11
Modern Quantum ComputersComputers areranked bynumber of qubitsdecoherency timeOperate at almostabsolute zero temperature-460 F or -273 C,colder than deep spaceQubitModalityApproximateDecoherencyTimes (ns)FidelitySpeed (MHz)Superconducting (IBM, Google,Rigetti)Trapped ions (IonQ, U. of Innsbruck)MaterialsAl on the Si substrateYb , Ca , Sr , Be , Ba , Mg TypeTransmonOptical transitionsControlMicrowavesMicrowaves opticsStateJunction phaseAtomic state of electron 100-200Very long1qb gate105,0002qb gate4050,0001qb gate99.9%99.999%2qb gate99.0%99.5%1qb gate100.000.202qb gate25.000.02Modern CPUs: 3 GHz, 100% fidelity12
IBM quantum computersThe key piece of the Quantum Computer is theDilution RefrigeratorWorking Temperature 15 mK uses mix of3He/4HeSource: IBM Research13
Available and announced quantum computersCompanyOperationalCloud AccessFrameworkAnnouncedIBM53 qubitsOpen to QQisKithub members100 qubit in 2021?Rigetti19 (8) qubitsAccess byrequestForest50 qubits in 2020?Google53 qubitsNo accessCirq72 qubit chip announcedMarch 2018Intel?No access?49 qubit chip announcedJan. 2018Alibaba11 qubits?AliyunIonQ11 qubitsNo accessAWS andAzureD-Wave2000Q ( 60qubits)Open (1minute permonth)Leap5000Q announced in201914
IBM quantum computersEverybody can get access through cloud (IBM Quantum et/qx/signupAvailable devices (public and Q hub):Qubits indeviceNumber of Publicdevices56615112040531015
Reality check We have 53 noisy qubits (need millions for computation) Short decoherency time limits execution up to 10-100 gatesmaximum (need millions) Slow gates MHz (need GHz) Poor connectivity (for superconducting quantum computers) Slow I/O Quantum Winter II for Quantum Computing in future?
Hybrid Quantum/Classical Computing SystemA high-level block diagram of a quantum computing system, where colors representdifferent levels of abstractions. Typically three levels are involved: a user level (blue),classical computation and control (yellow), and QC system (green). A quantum algorithmis compiled and mapped into a native set of instruction for the target quantum computer.The measurement of quantum register after postprocessing becomes the result.17
Quantum software stack18
Quantum circuitstimeQuantum computers are programmed byusing Quantum Assembly (QASM)QASM standards: MIT QASM, IBM OpenQASM2.0, LANL QASM, Atos QASM etc.Qbit q2Qbit q3Qbit q4H q2X q3H q3CNOT q3, q4X q3CNOT q3, q4H q2H q3X q3measure q0measure q119
A typical structure of a quantum algorithmInitialize Maximum superposition State preparation LogicGates Minimum superposition Measurement- First part of the algorithm is to make an equal superposition of all 2 n statesby applying H gates- The second part is to encode the problem into this states;put phases on all 2 n states- In the third part interfere all these states back to a few outcomescontaining the solution20
Quantum AlgorithmsUsefulalgorithmFast quantumalgorithmNo fastclassicalalgorithmexist There are two known classes algorithms hitting all three circles: Four main fundamental algorithms expected to provide a speedup overtheir classical counterparts: Shor's factoring algorithm, Grover's searchalgorithm, HHL’s linear system solver, and quantum simulation Quantum machine learning?21
Quantum cesQuantumspeedupRequirementsQuantumsimulation2N N6Exponential100 qubits,millions ofgatesFactorization2NN3Exponential200 qubits,millions ofgatesSolving linearsystemsN2Log(N)ExponentialMillions ofgates andqubitsUnstructuredsearchN N NMillions ofgates andqubitsN-complexity of the problem22
The Power of Quantum ComputationP solved in polynomial timeNP verified in polynomial timePSPACE solved in polynomial spaceWe do not know whetherP ! NPPSPACE is bigger than NPBQP (Bounded error Quantum Polynomialtime) is the class of decision problemssolvable by a quantum computer inpolynomial time, with an error probabilityof at most 1/3 for all instances
Moore’s LawCredit: Wikipedia24
Rose’s LawFor the past 10 years, the number of qubits on D-Wave's QPUs has beensteadily doubling each yearCredit: D-Wave25
Quantum Volume26
IBM Quantum Volume RoadmapCredit: IBM27
Acknowledgments This research used resources of the Argonne LeadershipComputing Facility, which is a DOE Office of Science UserFacility supported under Contract DE-AC02-06CH1135728
Quantum highly scalable C HPC code(MPI/OpenMP), freelyavailable from Gitunder development, nodocumentation, lackingsophisticated error modelsProjectQeasy to use Python code, freelyavailable from Git, works withOpenFermionno MPI implementation, lackingdocumentation, lacking errormodelsQuaCtime dynamics, scalable code,freely available from Git, errormodelsunder development, poordocumentations, depends onPETScAtosrobust commercial package,easy to use, excellentdocumentation, error modelsnot freely available, no MPIimplementation29
Simulating Quantum Computers On ClassicalComputers Simulating a quantum gate acting on N qubits needs O(2N) memory andoperationsQubitsMemoryTime per operation1016 KBMicroseconds on a smartwatch2016 MBMilliseconds on a smartphone3016 GBSeconds on a laptop4016 TBSeconds on a PC cluster5016 PBMinutes on modern supercomputers6016 EBHours on post-exascale supercomputers?7016 ZBDays on supercomputers in distant future?30
Quantum effects - superposition, interference, and entanglement NISQ - Noisy Intermediate-Scale Quantum technology, often refers in the context of modern very noisy quantum computers QASM - Quantum Assembly used for programming quantum computers Quantum supremacy - demonstration of that a programmable quantum
1. Quantum bits In quantum computing, a qubit or quantum bit is the basic unit of quantum information—the quantum version of the classical binary bit physically realized with a two-state device. A qubit is a two-state (or two-level) quantum-mechanical system, one of the simplest quantum systems displaying the peculiarity of quantum mechanics.
Quantum computing is a subfield of quantum information science— including quantum networking, quantum sensing, and quantum simulation—which harnesses the ability to generate and use quantum bits, or qubits. Quantum computers have the potential to solve certain problems much more quickly t
Topics History of Computing What are classical computers made of? Moore's Law (Is it ending?) High Performance computing Quantum Computing Quantum Computers Quantum Advantage The Qubit (Information in superposition) Information storage Different kinds of quantum computers Superconducting vs Ion Traps Annealing vs Universal/Gate quantum computers
Quantum computing with photons: introduction to the circuit model, the one-way quantum computer, and the fundamental principles of photonic experiments . quantum computing are presented and the quantum circuit model as well as measurement-based models of quantum computing are introduced. Furthermore, it is shown how these concepts can
Keywords—machine learning, quantum computing, deep learning, quantum machine intelligence I. INTRODUCTION There is currently considerable interest in quantum computing. In the U.S. in January 2019, the National Quantum Initiative Act authorized 1.2 billion investment over the next 5-10 years (Rep Smith, 2019). A quantum computing race is ongoing
According to the quantum model, an electron can be given a name with the use of quantum numbers. Four types of quantum numbers are used in this; Principle quantum number, n Angular momentum quantum number, I Magnetic quantum number, m l Spin quantum number, m s The principle quantum
the quantum operations which form basic building blocks of quantum circuits are known as quantum gates. Quantum algorithms typically describe a quantum circuit de ning the evolution of multiple qubits using basic quantum gates. Compiler Implications: This theoretical background guides the design of an e ective quantum compiler. Some of
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