Ababhungqi: Almudena Carrera Vazquez Caroline Tornow Diego Ristè Stefan Woerner Maika Takita Daniel J. Egger Isishwankathelo Iikhompyutha ze-Quantum ziqhuba ulwazi ngokusebenzisa imithetho ye-quantum mechanics. Iihardware zangoku ze-quantum zinengxolo, zikwazi ukugcina ulwazi ixesha elifutshane kwaye zilinganiselwe kwiibits ezimbalwa ze-quantum, oko kukuthi, ii-qubits, eziqhele ukulungiselelwa kuqhagamshelwano lwe-planar . Nangona kunjalo, usetyenziso oluninzi lwe-quantum computing kufuna uqhagamshelwano ngaphezu kwe-lattice ye-planar enikezelwa yi-hardware kwi-qubits ezininzi kunezo zikhoyo kwi-single quantum processing unit (QPU). Indibano kulindeleke ukuba ijongane nale mikhawulo ngokudibanisa iiPPU kusetyenziswa unxibelelwano lwekhasilensi, olungakavunywanga ngokwezivavanyo. Apha siphumeza iziphaluka eziguquguqukayo ezilawulwa ngempazamo kunye nokusika iziphaluka ukudala imilo ye-quantum efuna uqhagamshelwano rhoqo kusetyenziswa ukuya kuthi ga kwi-142 ii-qubits ezibandakanya iiPPU ezimbini ezinama-qubits ali-127 nganye edityaniswe ngexesha lokwenyani ngolayini wekhasilensi. Kwi-circuit eguquguqukayo, iigati ze-quantum zinokulawulwa yi-classical ngemvelo yezi-mid-circuit measurements ngexesha lokusebenza, oko kukuthi, ngaphakathi kwesahlulo sexesha lokuqhubeka kwe-qubits. Uluhlu lwethu lwangempela lwekhasi lekhasi lusivumela ukuba sisebenzise igeyithi ye-quantum kwi-QPU enye ngokuxhomekeka kwimvelo yokulinganisa kwenye i-QPU. Ngaphezu koko, ulawulo oluqinisekisiweyo lwempazamo lonyusa uqhagamshelwano lwe-qubit kunye neseti yemiyalelo ye-hardware ngoko ke yonyusa ukuguquguquka kweei-quantum computer zethu. Umsebenzi wethu ubonisa ukuba sinokusebenzisa ii-processor ezininzi ze-quantum njengenye kunye neziphaluka ezilawulwa ngempazamo ezihanjiswe yi-classical link yangempela. 1 Uhlengahlengiso Iikhompyutha ze-Quantum ziqhuba ulwazi olugqithisiweyo kwiibits ze-quantum kunye ne-unitary operations. Nangona kunjalo, ii-quantum computer zinengxolo kwaye uninzi lwee-architectures ezinkulu zibeka ii-qubits ezifanelekileyo kwi-lattice ye-planar. Nangona kunjalo, iiprosesa zangoku ezinolawulo lwempazamo zinokulinganisa imodeli ye-Ising ye-hardware nge-127 ii-qubits kwaye zilungelelanise izinto ezingabonakaliyo kwi-scale apho iindlela ezikhangayo ezinezikhompyutha zekhasilensi ziqala ukubandezeleka . Ukusebenza kwezibalo ze-quantum kuxhomekeke kukwandisa kunye nokoyisa uqhagamshelwano lwazo olulinganiselweyo lwe-qubit. Indlela ye-modular ibalulekile ekukaleni iiprosesa ze-quantum ezinengxolo kwaye ukufumana amanani amakhulu ee-qubits ezifanelekileyo zolwazi olungaphumeleliyo . I-trapped ion kunye ne-neutral atom architectures zinokufumana i-modularity ngokuhambisa i-qubits ngokwasemzimbeni , . Kwi-near term, i-modularity kwi-superconducting qubits ifunyenwa ngokunxibelelana okufutshane okudibanisa ii-chips ezijongene , . 1 2 3 4 5 6 7 8 Kwi-medium term, iigati ezide ezisebenza kwi-microwave regime zingasetyenziswa ngocingo olude lwesintu , , . Oku kungavumela uqhagamshelwano lwe-qubit olungajongekiyo olufanelekileyo kulwazi olusebenzayo . Enye indlela yexesha elide kukuphinda uqhagamshelane iiPPU ezikude kunye nolayini we-optical esebenzisa i-microwave ukuya kwi-optical transduction , okungakavunywanga, ngokokwazi kwethu. Ngaphezu koko, iziphaluka eziguquguqukayo zandisa iseti yeenguqu ze-quantum computer ngokwenza ii-mid-circuit measurements (MCMs) kunye nokulawula i-gate ngexesha lokuqhubeka kwe-qubits. Zonyusa umgangatho we-algorithmic kunye noqhagamshelwano lwe-qubit . Njengoko sizakubonisa, iziphaluka eziguquguqukayo zikwenza i-modularity ngokudibanisa iiPPU ngexesha lokwenyani ngolayini wekhasilensi. 9 10 11 3 12 13 14 Sithatha indlela eyongezelelweyo esekwe kwiigeyithi ezibonakalayo ukwenza imisebenzi emide kwi-architecture ye-modular. Sidibanisa ii-qubits kwizikhundla ezibonelelweyo kwaye sidala i-statistics ye-entanglement nge-quasi-probability decomposition (QPD) , , . Sithelekisa indlela ye-Local Operations (LO) kuphela kwelinye elongezwe yi-Classical Communication (LOCC) . Indlela ye-LO, ephumezwa kwiseti ye-two-qubit , ifuna ukuqhuba iziphaluka ezininzi ze-quantum kunye ne-local operations kuphela. Ngokungafaniyo, ukwenza i-LOCC, sisebenzisa ii-Bell pairs ezibonakalayo kwisiphaluka sokuhambisa ukudala iigeyithi ze-two-qubit , . Kwi-hardware ye-quantum enoqhagamshelwano olungaqhelekanga nolwe-planar, ukudala i-Bell pair phakathi kwee-qubits ezibonelelweyo kufuna igeyithi ye-controlled-NOT (CNOT) enoxhumo olude. Ukuphepha ezi geyithi, sisebenzisa i-QPD phezu kwee-operations ezifanelekileyo ezivelisa ii-Bell pairs ezisikiweyo ezisetyenziswa yi-teleportation. I-LO ayifuni i-classical link kwaye ngoko ke ilula ukuyenza kune-LOCC. Nangona kunjalo, njengoko i-LOCC ifuna isiphaluka setemplate esinye esinamaparameter, kusebenza ngakumbi ukuyilungisa kune-LO kwaye iindleko ze-QPD yayo ziphantsi kuneendleko zenkqubo ye-LO. 15 16 17 16 17 18 19 20 Umsebenzi wethu wenze igalelo elibalulekileyo eline. Okokuqala, sibonisa iziphaluka ze-quantum kunye ne-QPD ukudala ii-Bell pairs ezisikiweyo ezininzi ukwenza iigeyithi ezibonakalayo kwi-ref. . Okwesibini, sithintela kwaye silawule iimpazamo ezivela kwi-latency ye-classical control hardware kwi-dynamic circuits ngokudibanisa i-dynamical decoupling kunye ne-zero-noise extrapolation . Okwesithathu, sisebenzisa ezi ndlela ukuyila imiqathango ye-periodic boundary kwi-graph state ye-103-node. Okwesine, sibonisa unxibelelwano lwekhasilensi olwangempela phakathi kwama-QPU amabini ahlukeneyo ngoko ke sibonisa ukuba inkqubo ye-QPU ezisasazekileyo ingasetyenziswa njengenye ngolayini wekhasi . Idityaniswe neziphaluka eziguquguqukayo, oku kusivumela ukuba sisebenzise zombini ii-chips njengenye i-quantum computer, esiyibonakalisa ngokuyila i-graph state ye-periodic ebambe zombini izixhobo kwi-142 ii-qubits. Siyixoxa ngendlela yokuya phambili yokudala iigeyithi ezide kwaye sinikezela ngesigqibo sethu. 17 21 22 23 Ukusika iziphaluka Sisebenzisa iziphaluka ezinkulu ze-quantum ezingafakwanga ngqo kwi-hardware yethu ngenxa yemikhawulo yenani le-qubit okanye uqhagamshelwano ngokunquma iigeyithi. Ukusika iziphaluka kuqhekeka isiphaluka esiyinkimbinkimbi sibe zii-subcircuits ezingasetyenziswa ngabanye , , , , , . Nangona kunjalo, kufuneka sisebenzise inani elonyukileyo leziphaluka, esizibiza ngokuba yi-sampling overhead. Iziphumo ezivela kwezi-subcircuits zibuyiselwa kunye ngokwekhasi ukuze kuveliswe isiphumo sesiphaluka sokuqala ( ). 15 16 17 24 25 26 iiNdlela Njengoko enye yezona zinto ziphambili kwi-work yethu kukwenza iigeyithi ezibonakalayo nge-LOCC, sibonisa indlela yokudala ii-Bell pairs ezisikiweyo ezifunekayo kunye nee-local operations. Apha, ii-Bell pairs ezisikiweyo ezininzi ziyilwe ngeziphaluka ze-quantum ezineeparameter, esizibiza ngokuba yi-cut Bell pair factory (Fig. ). Ukusika ii-pairs ezininzi ngaxeshanye kufuna i-sampling overhead ephantsi . Njengoko i-cut Bell pair factory idala iziphaluka ezimbini ze-quantum ezahlukeneyo, sibeka isiphaluka ngasinye kufutshane nee-qubits ezinee-gates ezide. Umthombo osuka kuyo uze usebenze kwisiphaluka sokuhambisa. Ngokomzekelo, kwi-Fig. , ii-Bell pairs ezisikiweyo zisetyenziselwa ukudala iigeyithi ze-CNOT kwiipairs ze-qubit (0, 1) kunye (2, 3) (bona icandelo ‘ ’). 1b,c 17 1b Izifakelo ze-Cut Bell pair , Imbonakalo ye-IBM Quantum System Two architecture. Apha, ii-Eagle QPUs ezili-127 ziqhagamshelwe kunye nolayini wekhasi wangempela. Ngu-QPU nganye ulawulwa zii-electronics zayo kwirack yayo. Siyayilungisa ngokuchanekileyo zombini iiracks ukuze sisebenzise zombini iiPPU njengenye. , Isiphaluka setemplate ye-quantum sokwenza iigeyithi ze-CNOT ezibonakalayo kwiipairs ze-qubit ( 0, 1) kunye ( 2, 3) nge-LOCC ngokusebenzisa ii-Bell pairs ezisikiweyo kwisiphaluka sokuhambisa. Imigca emibini emnyama ibonisa uluhlu lwekhasilensi wangempela. , Izifakelo ze-Cut Bell pair 2( ) ezimbini ezisikiweyo ii-Bell pairs ngaxeshanye. I-QPD inenani elipheleleyo lezimbumbulu zeeparameter ezahlukeneyo ezingama-27 . Apha, . a b q q q q c C θ i θ i Imiqathango ye-periodic boundary Sakha isiphaluka segrafu | ⟩ kunye nemiqathango ye-periodic boundary kwi-ibm_kyiv, i-processor ye-Eagle , siyidlula imikhawulo ebekwe luqhagamshelwano lwayo lwangokwasemzimbeni (bona icandelo ‘ ’). Apha, inazo ∣ ∣ = 103 iinqununu kwaye ifuna imisebenzi emine emide eyi- lr = {(1, 95), (2, 98), (6, 102), (7, 97)} phakathi kwee-qubits eziphezulu nezisezantsi ze-processor ye-Eagle (Fig. ). Silinganisa ii-stabilizers zenqununu kwinqununu nganye ∈ kunye nee-stabilizers zamagxalaba ezakhiweyo yimveliso kulo lonke igxalaba ( , ) ∈ . Kwezi zigcini, sakha i-entanglement witness , ephantsi ukuba kukho i-entanglement phakathi kwemiphandla ( , ) ∈ (ref. ) (bona icandelo ‘ ’). Sigxile kwi-entanglement ebambenemiphandla kuba yiyo yona isisombululo esifuna ukuyiphinda ngeegates ezibonakalayo. Ukulinganisa ubungqina phakathi kwamaqela angaphezu kwabathathu kuza kulungelelanisa umgangatho weegates ezingezizo ezibonakalayo kunye nemilinganiso ekubenza kube nzima ukuqonda impembelelo yeegates ezibonakalayo. G 1 Iziphaluka zegrafu G V E 2a Si i V SiSj i j E i j E 27 Entanglement witness , I-graph ye-heavy-hexagonal igotyiweyo ngokwayo kwifomu ye-tubular ngeegxalaba (1, 95), (2, 98), (6, 102) kunye (7, 97) ezigqamisiweyo ngombala oluhlaza okwesibhakabhaka. Sinquma ezi gxalaba. , Ii-stabilizers zenqununu (phezulu) kunye nobume (bottom), kunye ne-1 standard deviation yeenqununu kunye namagxalaba asondeleyo kwiigxalaba ezide. Imigca eqhekekileyo ethe tye idibanisa ii-stabilizers kunye nee-witnesses ngokobude bazo kwiigxalaba ezinqunyulweyo. , Umsebenzi wokuhanjiswa ongadibananga weempazamo zesigcini. Iinkwenkwezi zibonisa ii-stabilizers zenqununu ezinogxalaba olwenziwe yigeyithi ende. Kwi-dropped edge benchmark (red dotted-dashed line), ii-gates ezide azenziwanga kwaye ii-stabilizers ezibonisiweyo ngeenkwenkwezi ngoko ke zine-unit error. Indawo engwevu yeyona mass yobuninzi ebalekayo eye-node stabilizers echaphazelekayo kukusika. a b Sj c Sj Silungisa i- | ⟩ sisebenzisa iindlela ezintathu ezahlukeneyo. Amagxalaba e-hardware alawulwa ngeegati ze-CNOT kodwa imiqathango ye-periodic boundary yenziwa nge (1) iigati ze-SWAP, (2) i-LOCC kunye (3) i-LO ukudibanisa ii-qubits kulo lonke i-lattice. Umehluko omkhulu phakathi kwe-LOCC kunye ne-LO li-operation yokuhambisa phambili equlunqwe ziimveliso ezingama-2 , apho liyinxalenye yokusika. Isiphaluka ngasinye sezizathu ezingama-22 sibangela imvumelwano eyahlukileyo ye- kunye/okanye iigati ze- kwi-qubits efanelekileyo. Ukufumana iziphumo zemveliso, ukumisela isizathu esifanelekileyo kunye nokusebenza ngokusekelwe kuso kwenziwa ngexesha lokwenyani yi-hardware yolawulo, ngeendleko zokubhideka okongeziweyo okungaguqukiyo. Siyilawula kwaye sithintele iimpazamo ezivela kule latency nge-zero-noise extrapolation kunye ne-staggered dynamical decoupling , (bona icandelo ‘ ’). G n n n X Z 22 21 28 Imiyalezo ye-quantum circuit eyilawulweyo ngempazamo Silinganisa ii-implementations ze-SWAP, LOCC kunye ne-LO ze- | ⟩ nge-graph state ye-hardware kwi- ′ = ( , ′) efumaneka ngokukhupha ii-gates ezide, oko kukuthi, ′ = lr. Isiphaluka esilungisa i- | ′⟩ ngoko ke sifuna kuphela iigati ezingama-112 ze-CNOT ezilungiselelwe kwiingqimba ezintathu zilandelana ne-heavy-hexagonal topology ye-Eagle processor. Esi siphaluka siya kuxela iimpazamo ezinkulu xa silinganisa ii-stabilizers zenqununu kunye nezigxalaba ze- | ⟩ kweenqununu kwi-gate enqunyulweyo kuba yenzelwe ukwenza i- | ′⟩. Sibhekisa kule-hardware-native benchmark njenge-dropped edge benchmark. Isiphaluka esisekelwe kwi-SWAP sifuna iigati ezingaphezulu ezingama-262 ze-CNOT ukudala ii-gates ezide ze- lr, okunciphisa kakhulu ixabiso lee-stabilizers ezilinganisiweyo (Fig. ). Ngokungafaniyo, i-LOCC kunye ne-LO implementation yeegxalaba kwi- lr ayifuni iigates ze-SWAP. Iimpazamo zazo ze-node kunye ne-edge stabilizers kweenqununu ezingabandakanyekiyo kwisigxobhozo zisondela kakhulu kwi-dropped edge benchmark (Fig. ). Ngokuchaseneyo, ii-stabilizers ezibandakanya igeyithi ezibonakalayo zinempazamo ephantsi kune-dropped edge benchmark kunye ne-swap implementation (Fig. , ii-markers zeenkwenkwezi). Njengesikali sokugqibelela, sixela kuqala isum yokugqibelela kweempazamo kwi-node stabilizers, oko kukuthi, ∑ ∈ ∣ − 1∣ (Extended Data Table ). I-overhead ye-SWAP enkulu ibangela i-44.3 sum absolute error. I-13.1 error kwi-dropped edge benchmark ibangelwa ziinqonqo ezisibhozo kwiisigxobhozo ezine (Fig. , ii-markers zeenkwenkwezi). Ngokungafaniyo, ii-LO kunye ne-LOCC errors zichaphazeleka yi-MCMs. Sixela impazamo eyongeziweyo eyi-1.9 ye-LOCC phezu kwe-LO kwii-latencies kunye nee-CNOT gates kwisiphaluka sokuhambisa kunye nee-Bell pairs ezisikiweyo. Kwi-results ezisekelwe kwi-SWAP, ayifumani i-entanglement kwiigxalaba ezingama-35 ezili-116 kwi-99% level yokuqinisekisa (Fig. ). Kwi-LO kunye ne-LOCC implementation, ibona i-statistics ye-entanglement ebambenemiphandla kulo lonke igxalaba kwi- kwi-99% level yokuqinisekisa (Fig. ). Ezi zikali zibonisa ukuba iigeyithi ezibonakalayo ezikude zivelisa ii-stabilizers ezineempazamo ezincinci kuneze-SWAP decompositions zazo. Ngaphezu koko, zigcina i-variance yanele ukufakazela i-statistics ye-entanglement. G G V E E EE G G G E 2b–d E 2b,c 2c i V Si 1 2c 2b,d G 2e Ukusebenza ii-QPU ezimbini njengenye Ngoku sidibanisa ii-Eagle QPUs ezimbini ezinama-qubits ali-127 nganye kwelinye i-QPU elinye ngenkxibelelwano yekhasilensi yangempela. Ukusebenza kwezixhobo njengenye, enkulu processor kukuqhuba iziphaluka ze-quantum ezibambene kunye nerejista enkulu ye-qubit. Ngaphandle kwee-unitary gates kunye nemilinganiso esebenza ngaxeshanye kwi-merged QPU, sisebenzisa iziphaluka eziguquguqukayo ukwenza iigates ezisebenza kwi-qubits kwiizixhobo zombini. Oku kwenziwa kuku synchronisation echazwe kakhulu kunye nonxibelelwano olukhawulezileyo lwekhasilensi phakathi kwezixhobo ezihlukileyo ngokwasemzimbeni ezifunekayo ukuqokelela iziphumo zemilinganiso kunye nokumisela ulawulo lwe-flow kuyo yonke inkqubo . 29 Sivavanya olu nxibelelwano lwekhasilensi yangempela ngokuyila isiphaluka segrafu kuma-qubits ali-134 akhiwe kwiingqungquthela ze-heavy-hexagonal ezijikeleza zombini iiPPU (Fig.
