(Fig.1) Even Google's latest Willow 105 qubits (= still Not a computer ) cannot correct errors, far inferior to today's errorless classical computers.
Overhyping media falsely said "Google's latest Willow quantum computer with (just) 105 qubits was a billion times faster than the (classical) supercomputers."
But at the same time, they said the contradictory thing; this Google quantum computer is still useless, No practical application. ← Paradox !
↑ If this quantum computer was really a billion times faster than the ordinary classical (super)computer, it should be definitely useful and replacing our PC, which did Not happen, which means this Google new quantum computer is useless, far slower (+ more error-prone ) than our ordinary practical classical computer, No quantum supremacy.
This Google quantum computer (= still Not a computer ) just output random useless numbers (= called random circuit sampling, this-5th-paragraph ) with estimated 99.9% error (or noise ) rate (= its fidelity was just 0.1%, this p.1-below-application performance-XEB fidelity = 0.1%, this-8~11th-paragraphs, this p.3(or p.2)-1st-paragraph ).
↑ Their actual error rate was probably worse than 99.9%, because it is impossible to know the true error rate only from random (meaningless) numbers.
This 3rd-paragraph says
"Google has since avoided talking about quantum supremacy... random circuit sampling or RCS... it has No known real-world applications"
This 2nd-paragraph says
"The calculation has almost No practical use—it spits out a string of random (useless) numbers ( this p.1-introduction ).... Useful quantum machines are many years away ( this 7~8th-paragraphs )"
An ordinary classical computer with billions of bits or transistors can calculate many complicated numbers including random numbers with zero error rate (= as shown in today's errorless PC you use ), so far superior to today's error-prone quantum computers with tiny numbers of qubits.
The present (fake) quantum supremacy or advantage claims are based on false assumption that their error-prone quantum computers (= still Not computers ) could get random (useless) numbers by utilizing (unseen, unfounded ) quantum superposition or 2105 illusory parallel universes ( this 1. ) that cannot be emulated by the practical classical computers using a single real world, so this is (fake) quantum speed-up ! ← nonsense ( this 6~10th-paragraphs ).
↑ No evidence of quantum speed-up based on (fantasy) quantum superposition or parallel worlds ( this-middle-superpositions;where do they go ? ), because only one state or one random bitstring number (= a dead or alive cat ) in one world can be observed after all ( this 9th-paragraph )
This 8th-last-paragraph says
"Willow is still well too small to do useful calculations, and that quantum computers will require "millions of qubits" to solve really important industry problems. Willow has 105 qubits (= still Not a computer, far from quantum advantage, No (fictional) parallel-universe power )"
Random numbers in today's fake quantum supremacy are just results of errors (= 99.9% error rate ), Not of quantum calculation utilizing (unfounded) parallel universes, so No evidence of quantum supremacy nor speed-up.
To deal with the error-prone qubits, Google tried to treat its whole 105 (or 101 ) qubits (= 105 bitstring ) as just one (logical) qubit expressing only 0 or 1 bit state, which (= just one bit ) is still Not a computer nor a calculator ( this-3rd-last~4th-last-paragaphs, this 3~4th-paragraphs ).
Because when they tried to express this single logical qubit = 1 bit state (= where all the 105 (physical) qubits composing this one logical qubit were made to be in the same "1" bit state ), even if 50 qubits of 105 (physical) qubits caused errors flipping 1 to 0, they could correct them into the initial 1 state, based on the remaining intact 55 qubits (= all 1 bit state ) by a majority vote.
↑ Even when they treated the whole 105 qubits as only one single (logical) qubit 0 or 1, this qubit worsened or increased its error (= logical error probability ) by 0.143% in each error correction cycle ( this-abstract, p.2-Fig.1c ). ← Quantum error correction was impossible ( this 6th-paragraph, this p.6-right-last-paragraph ).
This-2nd-last paragraph says
"the hardware remains far from the error rates required for extensive fault-tolerant computation."
This-lower-Will quantum computers arrive soon ? says
"Google concedes that Willow's error rate is still too high for quantum computing to be useful "
It is impossible that today's error-prone quantum computer whose error correction is impossible could be superior to the ordinary practical errorless classical computer, so No quantum supremacy nor speed-up.
↑ Actually, their paper published in Nature did Not claim quantum supremacy nor speed-up, contrary to the media-hype.
Overhyped quantum computers are harmful, misleading us and preventing curing deadly diseases.
Feel free to link to this site.
