ee times - ibm solves quantum computing

R.ColinJohnson4/29/201505:00AMEDT21comments

Tweet 75 15

News&Analysis

IBMSolvesQuantumComputing

GooglearchitectureobstacletocommercializationPORTLAND,Ore.Quantumcomputersarebeingpursuedbyallthemajorresearchlabsworldwide,includingevennewcomerslikeGoogle.However,IBMclaimsits30yearsofexperienceinquantumcomputingresearchshowsGoogleisallwronginits"linear"design,becauseIBM's"squaretiled"designcansolvebothofthemostimportantproblemsinquantumcomputingpluscanscaletoanysizeneededinthefuture.

IBM'ssearchfortherightarchitectureforquantumcomputersbeganin1981whenitattendedNobelPrizewinnerRichardFeynman'sfirstworkshoponthe"physicsofinformation"wherehelaidouttheconceptofaquantumcomputer.

Overthesubsequent34yearsIBMhasdevelopedFeynman'stheory,inventeditsownarchitectureandconductedexperimentsthattodayhaveledtothedevicesthatcanreliablyscaletoanynumberofqubitsextendingMoore'slawindefinitelysinceitwouldontakeonly50qubitstooutperformthefastestsupercomputerontheTop500.orgsupercomputerlist.

"Wearereportingonafourqubitsystemtoday,andalreadyexperimentingwithaneightqubitsystem,"JerryChow,managerofexperimentalquantumcomputinggroupatIBMResearchCenter(YorktownHeights,N.Y.)toldEETimes."Butunlikeotherdesigns,theseriesofproblemswehavejustsolvedcanscaletoasuperconductingquantumcomputerwithanynumberofqubits."

Thecurrentprototype(seephotos)issupercooledto15milliKelvin,usingacommerciallyavailablesuperrefrigerator,andhassolvedthetwomostimportantproblemsinquantumcomputingtoday,accordingtoIBM,thatissimultaneouslycorrectingforbitflipandphasefliperrorsaswellasbeingcompletelyscalabletoanysize.

Share 138

IBM'sfoursuperconductingquantumbitsuseasquarelatticetodetectbothtypesofquantumerrorsbiterrorsandphaseerrorsforthefirsttime.

(Credit:IBMResearch)

"Onthemarchtowardquantumcomputerserrorcorrectionisthemostimportantproblem,becausequbitsarenotasrobustasnormalcomputerbits,"Chowtoldus."Qubitsareveryfragileandcanbespoiledbyallsortsofnoiseintheenvironmentandintherestofthesystem."

Therearetwomaintypesoferrorsthatmustbecorrectedinquantumcomputersbiterrors(flippinga1toa0ora0toa1)andphasefliperrors(whichcausesignalstosubtractfromeachotherinsteadofadd).Unfortunately,itisverydifficulttosolveboththeseerrorsatonce.Todoso,IBMhadtogotoasquarearchitectureinsteadofalineararrayarchitecturelikeGoogle's,whichaccordingtoIBMcanonlysolveoneoftheproblemsortheotherbutnotboth.Asaresult,IBM'ssquarearrayoffourqubitsisquadrupleredundant,butitmakesanerrorfreescalablequantumcomputerpossible.

IBM'ssquarelayoutisthebestconfigurationtoaddmorequbitsandscaletolargersystems.(Credit:IBMResearch)

"Youneednearlyperfectqubitstodomeaningfulcalculationswithaquantumcomputer,soyouhavetodedicatesomequbitstoerrorcorrection,"Chowtoldus."Infact,weareworkingonaneightqubitarchitecturenowtocorrectotherpossibilitiesoferrorinasinglequbitandbelievethatitmaytake13to17qubitsormaybeevenmoretomakeasinglequbitperfectlyreliable."

Thereasonisthatqubitsdonotjustholdasingle0or1likeregularbits,butholdasuperpositionofvalues,"theyarepart0andpart1,whichiswhyitissohardtoperfectlypreservethenduringquantumcalculations,"Chowtoldus.

Inthecurrentfourqubitarchitecture,twoqubitsholdthevaluetobepreserved,whiletheothertwoqubitstellyouwhethertherehavebeenanybitfliporphasefliperrors,respectively.

IBM'sJerryChowinspectingaqubitinthequantumcomputinglabatIBM'sT.J.WatsonResearchCenter.(Credit:JonSimon/FeaturePhotoServiceforIBM)

NextIBMisshootingfortheHolyGrailofquantumcomputingtheperfectincorruptiblequbitthatcouldformthebasisofarealquantumcomputerscalabletoanysize.Toachievethatgoal,IBMplanstoextendthecurrentarchitecturebyaddingmorequbitsinan8bitsurfacecodelatticefornowthatwillofferevenbetterprotectionandcorrectionofquantumerrorsontheroadtotheperfectiontheyneedtostartmarketingrealquantumcomputers.

"Itmaytake8,13,17oreven49qubitsinascalablelatticetorealizetheHolyGrailofperfection,andthearchitecturemayhavetochangetorectangularorhexagonalorsomeothersymmetricalconfiguration,butwenowbelieveitisdefinitelyanachievablegoal."

IBM'squantumcomputingarchitectureusesscalablebuildingblocks,detectsandcorrectsquantumerrors,andwillbeablesolveproblemsconventionalcomputerscannot.

(Source:IBM)

Onceaquantumcomputerisperfecteditwillnotonlybeabletocrackanyencryptioncodetodayandmakenewuncrackablecodes,butwillalsoallowresearcherstounderstandphysicalprocessesthatareimpossibletosimulateoftraditionalcomputersForinstanceallthemolecularinteractionsthatmakecommonprocessesworkallowingdesignerstocreatematerialsimpossibletoimaginetoday,deriveinsightsfromunstructuredBigDatainaninstant,andtrulyunderstandusefulchemicalreactionsthattodaywereonlyfoundbytrialanderror.

"Quantumcomputerswillspawnaneweraofinnovationacrossallindustries,"Chowconcluded.

IBM'sworkwaspartiallyfundedtheU.S.IARPA(IntelligenceAdvancedResearchProjectsActivity)multiqubitcoherentoperationsprogram.

R.ColinJohnson,AdvancedTechnologyEditor,EETimes

Relatedarticles:

QuantumEntanglementNowOnaChipIBM'sWatsonDoesDeepLearningTooIBMtoBuildDoE'sNextGenCoralSupercomputersMoore'sLawHasNoEndinSightIBMConquersWaferScaleGraphene

Joinover2,000technicalprofessionalsandembeddedsystemshardware,software,andfirmwaredevelopersatESCBostonMay67,2015andlearnaboutthelatesttechniquesandtipsforreducingtime,cost,and

complexityintheembeddeddevelopmentprocess.

PassesfortheESCBoston2015TechnicalConferenceareavailableattheconferencesofficialsitewithdiscountedadvancepricinguntilMay1,2015.TheEmbeddedSystemsConferenceandEETimesareownedbyUBMCanon.