m acy ▁should ▁be ▁possible ▁with ▁a ▁" two - dimensional ▁lattice ▁of ▁ 7 x 7 ▁qu bits ▁and ▁around ▁ 4 0 ▁clock ▁cycles " ▁if ▁error ▁rates ▁can ▁be ▁pushed ▁low ▁enough . ▁On ▁June ▁ 1 8 , ▁ 2 0 1 9 , ▁Qu anta ▁Magazine ▁suggested ▁that ▁quantum ▁supre m acy ▁could ▁happen ▁in ▁ 2 0 1 9 , ▁according ▁to ▁Ne ven ' s ▁law . ▁On ▁September ▁ 2 0 , ▁ 2 0 1 9 , ▁the ▁Fin an cial ▁Times ▁reported ▁that ▁" Google ▁claims ▁to ▁have ▁reached ▁quantum ▁supre m acy ▁with ▁an ▁array ▁of ▁ 5 4 ▁q [ u ] bits ▁out ▁of ▁which ▁ 5 3 ▁were ▁functional , ▁which ▁were ▁used ▁to ▁perform ▁a ▁series ▁of ▁operations ▁in ▁ 2 0 0 ▁seconds ▁that ▁would ▁take ▁a ▁super comput er ▁about ▁ 1 0 , 0 0 0 ▁years ▁to ▁complete ". ▁On ▁October ▁ 2 3 , ▁Google ▁officially ▁confirmed ▁the ▁claims . ▁IBM ▁respond ed ▁by ▁suggesting ▁some ▁of ▁the ▁claims ▁are ▁excess ive , ▁and ▁suggested ▁that ▁it ▁could ▁take ▁ 2 . 5 ▁days ▁instead ▁of ▁ 1 0 , 0 0 0 ▁years . ▁ ▁Comput ational ▁complexity ▁▁ ▁Complex ity ▁arguments ▁concern ▁how ▁the ▁amount ▁of ▁some ▁resource ▁needed ▁to ▁solve ▁a ▁problem ▁( gener ally ▁time ▁or ▁memory ) ▁scales ▁with ▁the ▁size ▁of ▁the ▁input . ▁As ▁an ▁extension ▁of ▁classical ▁computational ▁complexity ▁theory , ▁quantum ▁complexity ▁theory ▁cons