Quantum History Part 4: NISQ and the Supremacy Claims (2018 to 2022)
Naming the era: NISQ
In January 2018 John Preskill posted a paper called "Quantum Computing in the NISQ era and beyond". NISQ stands for Noisy Intermediate-Scale Quantum. His argument, as the abstract summarizes it: devices with roughly 50 to 100 qubits might eventually do some tasks beyond today's classical computers, but gate noise limits how large a circuit can run reliably, and a 100 qubit machine will not transform computing overnight. He framed NISQ as a stepping stone toward fault tolerant machines. It is one of the most honest and useful framings in the field, and you can read more in NISQ Explained.
What is supremacy, and who named it
Preskill also coined the term quantum supremacy, the point where a programmable quantum computer does a task no classical computer can do in any feasible time, whether or not the task is useful. Some researchers dislike the word, and quantum advantage has largely replaced it in common use. The distinction between the two is covered in Quantum Supremacy vs Quantum Advantage Explained.
October 2019: Google's Sycamore
On October 23, 2019, Google published its result in Nature. Its blog post describes a 54 qubit programmable superconducting processor called Sycamore, arranged in a grid. The machine completed the target computation in 200 seconds, and Google estimated the world's fastest supercomputer would need about 10,000 years for a similar output. (The Wikipedia timeline describes it as 53 qubits in use, because one qubit was reported as not working. Sources use both numbers.)
IBM replied that with a better classical method on its Summit supercomputer, the same job could be done in about 2.5 days. That began a debate that has never fully ended: the bar moves because classical algorithms keep improving. It is a healthy sign, as the claim became a public test. Google's task, random circuit sampling, has no known practical use, so even the strongest reading is a proof of capability, not of usefulness.
December 2020: USTC enters
On December 3, 2020, a team in China led by Pan Jianwei at USTC reported Jiuzhang, a photonic machine doing Gaussian boson sampling with a peak of 76 detected photons. Their paper estimated a classical supercomputer would need about 2.5 billion years for the same number of samples. In 2021 Jiuzhang 2.0 reported 113 photons, and a superconducting processor called Zuchongzhi, with 66 transmon qubits, sampled 56 qubits. Photonic and superconducting approaches both had a credible claim, which showed the milestone was not a one lab trick. See Photonic Quantum Computing Explained.
The classical fight back
Reported follow ups showed classical researchers could trim these estimates dramatically with clever tensor network methods. Wikipedia reports that in 2024 Google's own team estimated that improved tensor network algorithms could simulate its 53 qubit experiment in about six seconds on the Frontier supercomputer. This does not erase the achievement. It shows science working: each claim sharpens the other side.
The qubit count race
Meanwhile the industry counted qubits. IBM presented its 127 qubit Eagle in November 2021, the 433 qubit Osprey in November 2022 and the 1,121 qubit Condor in December 2023. In June 2020 Honeywell (later merged into Quantinuum) announced a quantum volume of 64, then 512 in March 2021, and on April 14, 2022 claimed the first commercial system to pass quantum volume 4096. In May 2022 researchers in Innsbruck demonstrated a universal set of operations on fault tolerant qubits. The lesson: raw qubit counts and quality are different things, which is explained in Quantum Benchmarks Explained.
What this era gave us
- Public cloud access. Anyone can now run circuits on real hardware; see How to Try a Quantum Computer Online.
- Honest benchmarks. The supremacy fights pushed the field toward verifiable, comparable tests.
- A clear next target. Everyone agreed noise was the barrier, so effort shifted to error correction.
Next: the error correction era. Educational content, not investment advice.
Sources and further reading
- arXiv: Preskill, Quantum Computing in the NISQ era and beyond
- Google Research: Quantum supremacy using a programmable superconducting processor
- Wikipedia: Quantum supremacy
- Wikipedia: Timeline of quantum computing and communication
Reported as of 2026-10-09. Company claims are the companies' own unless a source says otherwise. Educational content only, not financial advice. The QNT memecoin is independent of Quantinuum Ltd and every other company, lab or government.
Frequently asked questions
What does NISQ mean?
Noisy Intermediate-Scale Quantum. It describes machines with tens to hundreds of imperfect qubits, a term introduced by John Preskill in 2018.
Did Google really achieve quantum supremacy in 2019?
Google reported it, and the result was published in Nature. IBM argued a classical computer could do the task in about 2.5 days, and later classical methods narrowed the gap further. The task also had no practical use.
Is quantum supremacy the same as quantum advantage?
They are closely related. Supremacy usually means beating any classical computer on any task, useful or not. Advantage is the more common term today and often implies a useful task.
Keep reading
- Quantum Supremacy vs Quantum Advantage Explained
What the terms quantum supremacy and quantum advantage mean, and why headline claims are often debated. - NISQ Explained: Noisy Intermediate-Scale Quantum Computers
What does NISQ mean? Learn why today's noisy, mid-size quantum computers are limited, what they can do, and how the field plans to move past them. - Quantum History Part 5: The Error Correction Era (2023 to 2026)
From four logical qubits in 2024 to Google's Willow, Quantinuum's Helios and a flood of logical qubit claims in 2026. - Quantum Benchmarks Explained: Why Qubit Count Misleads
How do you measure a quantum computer? Learn what error rates, fidelity, coherence time and quantum volume mean, and why qubit count alone is not enough.
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