麦肯锡-什么是量子计算？What is quantum computing 2024

April2024

Mcsey

company

McKinseyExplainers

Whatisquantumcomputing?

Quantumcomputingisanewapproachtocalculation

thatusesprinciplesoffundamentalphysicstosolve

extremelycomplexproblemsveryquickly.

Flipacoin.Headsortails,right?Sure,onceweseehowthecoinlands.Butwhilethecoinisstillspinning

intheair,it’sneitherheadsnortails.It’ssomeprobabilityofboth.

Thisgrayareaisthesimplifiedfoundationofquantumcomputing.

Digitalcomputershavebeenmakingiteasierfor

ustoprocessinformationfordecades.Butquantumcomputersarepoisedtotakecomputingtoa

wholenewlevel.

Quantumcomputers

represent

acompletelynewapproachtocomputing.They

havethepotentialto

solve

verycomplexstatisticalproblemsthatarebeyondthelimitsoftoday’s

computers.Quantumcomputinghassomuch

promise

andmomentumthatMcKinseyhasidentifieditasoneofthe

nextbigtrendsintech

.Quantum

computingalone—justoneofthreemainareasofemergingquantumtechnology—couldaccount

for

nearly$1.3trillioninvalue

by2035.Investorsofallkindsareperkinguptheirears—andopening

uptheirwallets:governmentinvestorsalonehavepledged

$34billion

ininvestments.In2022,theUSgovernmentannounced$1.8billioninfunding,bringingitstotalinvestmentto$3.7billion.

LearnmoreaboutMcKinseyDigital.

Howdoesaquantumcomputerwork?

Here’showquantumcomputingworks:classical

computing,thetechnologythatpowersyourlaptopandsmartphone,isbuiltonbits.Abitisaunitof

informationthatcanstoreeitherazerooraone.Bycontrast,quantumcomputingisbuiltonquantum

bits,orqubits,whichcanstorezerosandones.Qubitscanrepresentanycombinationofbothzeroand

onesimultaneously—thisiscalledsuperposition,anditisabasicfeatureofanyquantumstate.

Chipsarethephysicalhardwarethatstorequbits,justlikeinclassicalcomputing.

Whenaclassicalcomputersolvesaproblemwith

multiplevariables,itmustconductanewcalculationeverytimeavariablechanges.Eachcalculationis

asinglepathtoasingleresult.Quantumcomputers,

however,canexploremanypathsinparallelthroughsuperposition.

Additionally,qubitscaninteractwithoneanother.Thisisknownasentanglement.Entanglement

allowsqubitstoscaleexponentially;twoqubits,forexample,canstoreandprocessfourbitsof

information,threecanprocesseight,andsoon.Thisexponentialscalinggivesthequantumcomputer

muchmorepowerthanclassicalcomputers.

Heavyweighttechorganizationsarealreadyplacingbetsonquantumtechnology.In2019,Google

claimedthatitsquantumcomputerhadsolvedin

just200secondsaproblemthatwouldhave

takenaclassicalcomputer10,000years(although

othertechorganizationsandacademics

have

surfaceddoubts

aboutthevalidityofGoogle’sclaim).

EvenifGoogle’sclaimwasaccurate,theachievementwasmoreofatheoreticalleapforwardthana

practicalonesincetheproblemitsquantumcomputersolvedhadnoreal-worlduse.Butwe’rerapidly

approachingatimewhenquantumcomputerswillhavearealimpactonourlives.

Whatarequantumcomputersusedfor?

Today’sclassicalcomputersarerelativelystraight-forward.Theyworkwithalimitedsetofinputsanduseanalgorithmandspitoutananswer—andthe

bitsthatencodetheinputsdonotshareinformationaboutoneanother.Quantumcomputersare

different.Foronething,whendataareinputinto

thequbits,thequbitsinteractwithotherqubits,

allowingformanydifferentcalculationstobedonesimultaneously.Thisiswhyquantumcomputersare

abletoworksomuchfasterthanclassicalcomputers.

Butthat’snottheendofthestory:quantum

computersdon’tdeliverjustoneclearanswerlikeclassicalcomputersdo;rather,theydelivera

rangeofpossibleanswers.

Forcalculationsthatarelimitedinscope,classicalcomputersarestillthepreferredtools.Butfor

verycomplexproblems,quantumcomputerscan

savetimebynarrowingdowntherangeof

possibleanswers.

Whatisquantumcomputing?2

Whenwillquantumcomputers

beavailable?

Overthenextfewyears,themajorplayersin

quantumcomputing,aswellasasmallcohortofstart-ups,willsteadilyincreasethenumberof

qubitsthattheircomputerscanhandleandimprovehowthetechnologyfunctions.Progressinquantumcomputing,however,isexpectedtoremainslow.

Accordingtoourconversationswithtechexecutives,investors,andacademicsinquantumcomputing,

72percent

believewe’llseeafullyfault-tolerant

quantumcomputerby2035.Theremaining

28percentthinkthismilestonewon’tbereacheduntil2040orlater.

Butsomebusinesseswillbegintoderivevalue

fromquantumwellbeforethen.Atfirst,businesseswillreceivequantumservicesviathecloud.

Severalmajorcomputingcompanieshavealreadyannouncedtheirquantumcloudofferings.

LearnmoreaboutMcKinseyDigital.

Whataresomeobstaclesthat

impedethedevelopmentof

quantumcomputing?

Onemajorobstacletotheadvancementofquantumcomputingisthat

qubitsarevolatile

.Whereasabitintoday’sclassicalcomputersisinastateofeitheroneorzero,aqubitcanbeanypossiblecombinationofthetwo.Whenaqubitchangesitsstatus,inputs

canbelostoraltered,throwingofftheaccuracyoftheresults.Anotherobstacletodevelopmentisthataquantumcomputeroperatingatthescaleneededtodeliversignificantbreakthroughswillrequire

potentiallymillionsofqubitstobeconnected.Thefewquantumcomputersthatexisttodayare

nowherenearthatnumber.

Herearesomeotherchallengesfacingthe

technologies

thatcouldsupportquantumcomputingatscale:

—High-fidelitytwo-qubitgatesatscale.

Maintaininghighfidelity(meaningaccuracyandreliabilitygreaterthan99.99percent)is

requiredforfault-tolerantquantumcomputers.Doingsoatscalewillbedifficult.

—Speed.Qubitsneedtoretaintheirquantumstatetobeabletointeractwithoneanother.Even

inspecificenvironmentalconditions,theywill

eventuallydegrade.Forquantumcomputers

tooperateatscale,gateoperationswillneedtomoveveryquicklytocompletecomputations

beforequbitsdegrade.

—Multiqubitnetworking.Connecting,ornetwork-ing,qubitstooneanothercouldtheoretically

makequantumcomputersmuchmorepowerful.Thekeychallengehereisconnectingqubits

acrosschips,orfromonephysicalquantumcomputertoanother.

Seventy-twopercentoftechexecutives,investors,andacademicsbelievewe’llseeafullyfault-tolerantquantumcomputerby2035;28percentthinkthismilestonewon’tbereacheduntil2040orlater.

Whatisquantumcomputing?3

—Individualqubitcontrolatscale.Thecontrolofindividualqubitsbecomesincreasinglycomplexasthenumberofqubitsincreases.

—Coolingpowerandenvironmentalcontrol.As

quantumcomputersbecomelarger,thesizeandpowerrequirementsofthecoolingequipment

becomemoreandmoreexpensive,frombothacostandanenvironmentalstandpoint.Currently,poweringaquantumcomputerlargeenough

toconnectmillionsofqubitsiscostprohibitive.

—Manufacturability.Producinglargenumbersofquantumcomputerswillrequireautomating

boththemanufacturingandtestingprocesses.Theproductionofcertainquantumcomputersmayrequiredevelopingentirelynew

manufacturingtechniques.

Howcanclassicalcomputersand

quantumcomputersworktogether?

Slowly,atfirst.Initially,quantumcomputing

willbe

usedalongside

classicalcomputingtosolve

multivariableproblems.Oneexample?Quantum

computerscannarrowtherangeofpossible

solutionstoafinanceorlogisticsproblem,helpingacompanyreachthebestsolutionfaster.This

kindofslowerprogresswillbethenormuntil

quantumcomputingadvancesenoughtodelivermoresignificantbreakthroughs.

LearnmoreaboutMcKinseyDigital.

Whataresomepotentialbusinessusecasesforquantumcomputers?

Quantumcomputershave

fourfundamental

capabilities

thatdifferentiatethemfromtoday’sclassicalcomputers:

1.Quantumsimulation.Quantumcomputerscanmodelcomplexmolecules,whichmayeventuallyhelpreducedevelopmenttimeforchemicalandpharmaceuticalcompanies.Scientistslookingtodevelopnewdrugsneedtoexaminethestructureofamoleculetounderstandhowitwillinteract

withothermolecules.It’salmostimpossiblefor

today’scomputerstoprovideaccurate

simulations,becauseeachatominteractswithotheratomsincomplexways.Butexperts

believethatquantumcomputersarepowerfulenoughtoeventuallybeabletomodeleven

themostcomplexmoleculesinthehuman

body.Thisopensupthepossibilityfor

faster

development

ofnewdrugsandnew,

transformativecures.

2.Optimizationandsearch.Everyindustryreliesinonewayoranotheronoptimization.Where

arerobotsbestplacedonafactoryfloor?What’stheshortestrouteforacompany’sdelivery

trucks?Therearealmostinfinitequestionsthatneedtobeansweredtooptimizeforefficiency

andvaluecreation.Withclassicalcomputing,companiesmustmakeonecomplicated

calculationafteranother,whichcanbeatime-consumingandcostlyprocessgiventhemanypotentialvariablesofasituation.Sincea

quantumcomputerisabletoworkwithmultiplevariablessimultaneously,itcanbeusedto

quicklynarrowtherangeofpossibleanswers

.Fromthere,classicalcomputingcanbeusedtozeroinononepreciseanswer.

3.QuantumAI.Quantumcomputershavethe

potentialtoworkwithbetteralgorithmsthat

couldtransformmachinelearningacrossa

diverserangeofindustries,fromautomotivetopharmaceuticals.Inparticular,quantum

computerscouldacceleratethearrivalofself-drivingvehicles.CompanieslikeFord,GM,

Volkswagen,andnumerousmobilitystart-upsarerunningvideoandimagedatathrough

complexneuralnetworks.Theirgoal?Touse

AItoteachacartomakecrucialdrivingdecisions.

Quantumcomputers’abilitytoperformmultiplecomplexcalculationswithmanyvariables

simultaneouslyallowsfor

fastertraining

ofsuchAIsystems.

4.Primefactorization.Businessestodayuse

large,complexprimenumbersasthebasisfortheirencryptionefforts,numberstoolarge

forclassicalcomputerstoprocess.Quantumcomputingwillbeabletousealgorithmsto

solvethesecomplexprimenumberseasily,a

Whatisquantumcomputing?4

Quantumcomputingcouldresultinamobilityecosystemthat

isfullyconnected,intelligent,andenvironmentallyfriendly.

processcalledprimefactorization.(Infact,a

quantumalgorithmknownasShor’salgorithmtheoreticallyalreadycan;there’sjustnota

computerpowerfulenoughtorunit.)Once

quantumcomputershaveadvancedenough,

newquantum-encryptiontechnologieswill

beneededto

protectonlineservices

.Scientistsarealreadyatworkonquantumcryptography

toprepareforthiseventuality.McKinsey

estimatesquantumcomputerswillbepowerfulenoughforprimefactorizationbythelate

2020sattheveryearliest.

Asthesecapabilitiesdevelopatpacewithquantumcomputingpower,usecaseswillproliferate.

Whatindustriesstandtobenefitthemostfromquantumcomputing?

Researchsuggeststhatseveralindustriesinpar-

ticularstandtoreapthegreatestshort-termbenefitsfromquantumcomputingbasedontheusecases

discussedintheprevioussection.Collectively—and

conservatively—thevalueatstakefortheseindustriescouldbeinthetrillionsofdollars.

—Pharmaceuticals.Quantumcomputinghas

thepotentialtorevolutionizetheresearchand

developmentofmolecularstructuresinthe

biopharmaceuticalsindustry.Withquantum

technologies,researchanddevelopment

fordrugscouldbecomelessreliantontrialanderror,andthereforemoreefficient.(

Readmore

onhowquantumcomputingstandstoaffectthe

pharmaceuticalindustry.

)

—Chemicals.Quantumcomputingcouldbe

usedtoimprovecatalystdesign,whichcouldenablesavingsonexistingproduction

processes.Innovativecatalystscouldalsoenablethereplacementofpetrochemicalswithmoresustainablefeedstockorthe

breakdownofcarbonforCO₂usage.(

Read

moreonhowquantumcomputingmight

affectthechemicalsindustry.

)

—Mobility.Quantumcomputingcouldresult

inamobilityecosystemthatisfullyconnected,intelligent,andenvironmentallyfriendly.

Changesdependontherapidandsmoothexchangeofvastamountsofdatabetween

in-vehiclecomputersandcomputerselsewhere.Quantumcomputerscanprocessthese

largeamountsofdatainwaysexistingcomputers

can’t,makingthistypeofdataexchange

arealisticpossibility.(

Readmoreabouthow

quantumtechnologiescouldaffectthe

mobilityindustry.

)

—Automotive.Withinthemobilitysector,the

automotiveindustrycouldbenefitfromquantumcomputinginitsR&D,productdesign,supply

chainmanagement,production,andmobility

andtrafficmanagement.Forexample,quantumcomputingcouldbeappliedtodecrease

manufacturingcostsbyoptimizingcomplexmultirobotprocessesincludingwelding,

gluing,andpainting.(

Readmoreabouthow

quantumtechnologiescouldaffectthe

automotiveindustry

.)

Whatisquantumcomputing?5

—Finance.Quantumcomputingusecasesin

financeareslightlyfurtherinthefuture.

Thelong-termpromiseofquantumcomputinginfinanceliesinportfolioandriskmanagement.

Oneexamplecouldbequantum-optimizedloanportfoliosthatfocusoncollateraltoallow

lenderstoimprovetheirofferings.Bythetimeafault-tolerantquantumcomputerisavailable,weestimatethattheusecasesinfinance

couldcreate

$622billioninvalue

.(

Readmore

abouthowquantumcomputingcouldaffect

financialservices

.)

Thesefiveindustrieslikelystandtogainthemostfromquantumcomputing,atleastatfirst.But

leadersineverysectorcan—andshould—preparefortheinevitablequantumadvancementsofthe

comingyears.

LearnmoreaboutMcKinseyDigital.

Whataretheotherquantum

technologiesasidefromcomputing?

AccordingtoMcKinsey’sanalysis,quantum

computingisstillyearsawayfromwidespreadcommercialapplication.Otherquantum

technologiessuchasquantumcommunication(QComms)andquantumsensing(QS)could

becomeavailable

muchearlier

.

Quantumcommunicationwillenablestrong

encryptionprotocolsthatcouldgreatlyincrease

thesecurityofsensitiveinformation.QCommscanhelpfacilitatethefollowingfunctions:

—Fullsecuritywheninformationistransferred

betweenlocations.Quantum-encryption

protocolsaremoresecurethanclassical

protocols,mostofwhichwilllikelybeabletobe

brokenoncequantumcomputersattain

morecomputingpowerorcanworkwithmoreefficientalgorithms.

—Enhancedquantumcomputingpowerintwo

importanttypesofquantumprocessing:parallelquantumprocessing(wheremultipleprocessorsareconnectedandsimultaneouslyexecute

differentcalculationsfromthesameproblem)andblindquantumcomputing(wherequantumcommunicationsprovideaccesstoremote,

large-scalequantumcomputersinthecloud).Bothtypesofprocessingaremadepossiblebytheentanglementofquantumparticles.

Entanglementiswhenquantumparticleslikequbitshaveconnectedproperties,which

meansoneparticle’spropertiescanbemanip-ulatedbyactionsdonetoanother.

Quantumsensingallowsformoreaccuratemeasure-

mentsthaneverbefore,includingofphysical

propertiesliketemperature,magneticfields,androtation.Plus,onceoptimizedanddecreasedin

size,quantumsensorswillbeabletomeasuredatathatcan’tbecapturedbycurrentsensors.

ThemarketsforQCommsandQSarecurrently

smallerthanthemarketforquantumcomputing,whichhassofarattractedmostoftheheadlines

andfunding.ButMcKinseyexpectsbothQcommsandQStoattractseriousinterestandfunding

inthefuture.Therisksaresignificant,butthe

potentialpayoffishigh:by2030,QSandQCommscouldgenerate$13billioninrevenues.

Learnmoreaboutquantumsensorsand

quantumcommunications.

Howcanorganizationsensurethattheyhavethequantumcomputingtalenttheyneed?

Awidetalentgap

existsbetweenthebusinessneedforquantumcomputingandthenumberofquantumprofessionalsavailabletomeetthat

need.Thisskillsgapcouldjeopardizepotentialvaluecreation,whichMcKinseyestimatesto

beasmuchas$1.3trillion.

Thetalentgapis

feltdifferently

bycompaniesofdifferentsizes.Smallstart-upsworkinginthe

quantumspacetypicallygrowoutofuniversity

researchlabsandoftenhavedirectaccessto

skilledcandidates.Largercompaniesmighthavelessofaconnectiontothesetalentpools.

Whatisquantumcomputing?6

McKinseyresearchhasfoundthatthereis

onlyone

qualifiedquantumcandidate

foreverythreequantumjobopenings.By2025,McKinseypredictsthatlessthan50percentofquantumjobswillbefilledunlesstherearesignificantchangestothetalentpoolor

predictedrateofquantum-jobcreation.

HerearefivelessonsderivedfromtheAItalentjourneythatcanhelporganizationsbuildthequantumtalenttheyneedtocapturevalue:

—Defineyourtalentneedsclearly.Intheearly

daysofAI,someorganizationshireddata

scientistswithoutaclearunderstandingofwhatskillswereneeded.Toavoidmakingthesame

errorwithquantum,organizationsshouldfirstidentifypossiblefieldsofapplicationsthata

quantumcomputingteamwouldworkonandthenensurethatnewhirescomefromdiversebackgrounds(reflectingbestpractices).

—Investearlyintranslators.Asbuzzbuiltup

aroundAI,theroleofanalyticstranslators

becamecrucialtohelpingleadersidentifyandprioritizechallengesbestsuitedforAIto

solve.Withquantum,there’sasimilarneed:

fortranslatorswithengineering,application,

andscientificbackgroundswhocanhelp

organizationsunderstandtheopportunitiesandplayersintherapidlyexpandingecosystem.

basicunderstandingofhowitworksandwhatitcando.Withquantum,businessleadersaswellasworkersupanddownthesupplychain,in

marketing,ITinfrastructure,finance,andmorewillrequirebasicfluencyinquantumtopics.

5.Don’tforgettalentdevelopmentstrategies.

Companiesfocusheavilyontalentattraction

duringtimesoftechnologicalfoment,butthat’sjustonepieceofthetalentpuzzle.Toretain

specialists,companiesneedtocarveoutclear

pathsfortalentdevelopment.Onepharmaceuticalcompanyleansintoboththepurposeofits

work—developingusecasesthatwillhelpsavelives—andthefreedomitoffersitsteam.

LearnmoreaboutMcKinseyDigital

andcheckout

quantumcomputingjobopportunities

ifyou’re

interestedinworkingatMcKinsey.

Articlesreferenced:

—“

Quantumtechnologyusecasesasfuelforvalue

infinance

,”October23,2023,Martina

Gschwendtner,NicoleMorgan,

HenningSoller

—“

Gearingupformobility’sfuturewithquantum

computing

,”September13,2023,ScarlettGao,

TimoMöller

,

NikoMohr

,AlexiaPastré,

FelixZiegler

—Createpathwaysforadiversetalentpipeline.

ManyofthefirstAImodelsreflectedthesame

biasesthatwerepresentintheinformationthatwasusedtotrainthem.Thereoftenwasalso

alackofpeoplewithdiverseperspectivesand

experiencebuildingandtestingthemodels,

whichcontributedtothebiasissue.Whileit’stooearlytoknowalltherisksthatcouldemerge

fromquantum,wecanexpectsimilarchallengesifadiverseandempoweredquantumworkforceisnotinplacetoworkwiththisnewtechnology.

Effortsareneededattheuniversitylevel,aswellasinK–12education.

—Buildtechnologyliteracyforall.Foremployeesatalllevelsofanorganizationtounderstand

thepotentialofanewtechnology,theyneeda

—“

Iswintercoming?Quantumcomputing’s

trajectoryintheyearsahead

,”May19,2023,ScarlettGao,MartinaGschwendtner,HusseinHijazi,NicoleMorgan,

HenningSoller

—“

Quantumtechnologyseesrecordinvestments,

progressontalentgap

,”April24,2023,MichaelBogobowicz,ScarlettGao,MateuszMasiowski,

NikoMohr

,

HenningSoller

,

RodneyZemmel

,

MatijaZesko

—“

FivelessonsfromAIonclosingquantum’stalent

gap—beforeit’stoolate

,”December1,2022,

NikoMohr

,KieraPeltz,

RodneyZemmel

,andMatijaZesko

Whatisquantumcomputing?7

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—“

Frombasicresearchtomarket:Whytherecent

NobelPrizeinphysicsmatters

,”October18,2022,MenaIssler,

NikoMohr

,and

HenningSoller

—“

Quantumcomputingfundingremainsstrong,

buttalentgapraisesconcern

,”June15,2022,MateuszMasiowski,

NikoMohr

,

HenningSoller

,andMatijaZesko

—“

Howquantumcomputingcanhelptackleglobal

warming

,”May27,2022,JeremyO’Brien

—“

Quantumcomputingjustmightsavetheplanet

,”May19,2022,PeterCooper,PhilippErnst,

DieterKiewell

,andDickonPinner

—“

Sh