DAƘIƘA 19 DA ƘARNI ƊAYA NA SUPERCOMPUTER

Fifikon quantum (quantum advantage) yana nufin nuna cewa kwamfutar quantum na iya yin aikin da babu supercomputer ta gargajiya da za ta iya kammalawa cikin lokaci mai ma’ana. Daidaitaccen gwajin shi ne ɗaukar samfura daga da’irori na bazuwar (random-circuit sampling): a yi amfani da jerin ƙofofin quantum da aka zaɓa bazuwar a kan qubit da dama, sannan a auna su. Sakamakon shi ne kwararar jerin 0 da 1 da aka ɗiba daga wani rarraba na yiwuwa wanda kwamfutocin gargajiya ke sha wahala matuƙa wajen sake samarwa.

Wani muhimmin batu: wannan aiki ba shi da amfani a zahiri. Ma’aunin kwatanci ne — agogon auna ɗanyen ƙarfin lissafi.

Tsere daga ɓangarori biyu

Processor ɗin Sycamore ne ya buɗe tseren da qubit 53, sai Zuchongzhi 2.0 da 2.1, Sycamore mai qubit 67, da Zuchongzhi 3.0 mai qubit 83 masu aiki. A ɗaya ɓangaren, hanyoyin lissafi na gargajiya sun ci gaba da inganta kuma sun rage farashin sake samar da waɗannan gwaje-gwaje da matakai da yawa na girma. Don haka kowane iƙirari dole ne ya faɗi daidai da wane aiki na gargajiya ake kwatanta shi.

Har zuwa yanzu, dukkan waɗannan nune-nunen an yi su ne a kan injinan ɗakin gwaji na musamman, waɗanda aka daidaita su da kyau domin wannan lokacin.

Processor da aka yi haya ta hanyar cloud

Wata ƙungiya daga sabon kamfanin BlueQubit (San Francisco), tare da abokan aiki a EPFL da Gidauniyar XPRIZE, ta yi amfani da processor IBM Nighthawk r2: qubit 120 masu superconducting a kan raga murabba’i ta 12 × 10. Sun shiga gare shi ta hanyar cloud, da kayan aikin Qiskit na IBM na yau da kullum, kuma ba tare da wani daidaitawa na musamman ba. Marubutan ba daga IBM suke ba: sun yi amfani da injin ta shirin IBM na sabbin kamfanoni kuma sun bayyana cewa ra’ayoyinsu ba na IBM ba ne.

Sun yi amfani da qubit 61 — an bar uku a waje saboda bayanan daidaitawarsu — waɗanda aka haɗa da masu haɗawa (couplers) 102.

Duba sakamakon kai tsaye ba zai yiwu ba: wannan shi ne ainihin abin da kwamfutocin gargajiya ba za su iya yi ba. Don haka ƙungiyar ta yi amfani da ƙiyasi biyu masu zaman kansu na amincin (fidelity) da’irar:

• gwajin “madubi”: a gudanar da da’ira, sannan ainihin juyinta, a duba ko qubit sun koma inda suka fara — ba a buƙatar kwaikwayo;
• gwajin “faci”: a yanka da’irar zuwa guda 3 ko 4 ƙanana da za a iya kwaikwayonsu, a duba kowane guda.

Lambobin

• Ƙiyasin biyu sun yi daidai a kowane zurfi da aka auna.
• Amincin kowane zagaye: 0.872, idan aka kwatanta da 0.836 a ƙarni na farko Nighthawk r1 — fiye da sau goma mafi kyau bayan zagaye 32 zuwa 40.
• Ma’aunin tunani: zagaye 36, ƙofofin qubit biyu 918, amincin kusan 0.0023. An tattara samfura miliyan ɗaya cikin daƙiƙa 19.
• Lissafa yiwuwar fitarwa ɗaya kawai ta hanyar gargajiya yana ɗaukar kusan ayyuka 10²² — kusan kwanaki biyu na supercomputer Frontier.
• Samar da samfura miliyan ɗaya iri ɗaya ta hanyar gargajiya: kusan ayyuka 1.2 × 10²⁷, ko kusan shekaru 110 a kan Frontier.
• Dukkan gwajin ya yi amfani da kusan mintuna 11 na lokacin kwamfutar quantum.
• “Dabarun cuta” na gargajiya da aka sani — yanka da’irar zuwa guda don kwaikwayon maki — sun gaza aƙalla sau goma ga makin da aka auna.

Rubutu ƙanana

Shekaru 110 ƙiyasi ne ga wata takamammiyar hanyar lissafi ta gargajiya, ba cikakkiyar iyaka ba. Yana ɗaukar ƙwaƙwalwa marar iyaka, abin da ke amfanar ɓangaren gargajiya. Wasu hanyoyi — sake amfani da aiki a kan yiwuwa da yawa, kwaikwayo na kusan-kusan — za su iya rage farashin. Kuma, marubutan sun rubuta, tarihin wannan ma’aunin kwatanci ya nuna cewa wasu daga cikinsu za su yi hakan.

Ma’aunin kwatanci da kowa zai iya sake gudanarwa

A cewar marubutan, wannan shi ne nuni na farko na fifikon quantum a daidaitaccen ɗaukar samfura daga da’irori na bazuwar a kan processor na kasuwanci, wanda ake samu a ko’ina, wanda yawancin masu amfani da ba ƙwararru ba za su iya maimaitawa. Da’irorin, bayanan — har da samfura miliyan ɗaya — da lambar kwamfuta duk a buɗe suke ga kowa.