South Korea Quantum Computer 100 Microseconds Explained: Qubits Now Hold Their State Twice as Long as the 2027 Target

South Korea quantum computer 100 microseconds explained: a quantum computer with superconducting qubits

Illustrative image: a quantum computer. Image: Wikimedia Commons / OJB Quantum, CC BY 4.0

TL;DR — South Korea quantum computer 100 microseconds explained in one line: at a government meeting in Daejeon on 10 November 2026, South Korean researchers reported superconducting qubits that hold their quantum state for more than 100 microseconds — double the 50-microsecond target set for 2027 — with about 99% accuracy on two-qubit operations. It is a national research milestone, not a machine you can buy, and the next test is turning it into an error-corrected 100-qubit processor by 2029.

Key Highlights

Coherence past 100 microseconds. Superconducting qubits now keep their quantum state for more than 100 microseconds — roughly twice the 50-microsecond target South Korea set for 2027.
Two-qubit accuracy of about 99%. Researchers confirmed around 99% accuracy on entangling operations between two qubits, the basic computation a quantum processor must get right.
Announced 10 November 2026 at the annual meeting of the Quantum Science and Technology Flagship Project in Daejeon, run by the Ministry of Science and ICT.
More than computing. The same meeting unveiled two quantum repeater designs for long-distance quantum networks and a diamond-based sensor that reads the heart's magnetic field.
₩360.4 billion behind it. The flagship project invests about 360.4 billion won (around $266 million) from 2025 to 2029 across 26 tasks — and aims for an error-corrected 100-qubit-class processor by 2029.

What happened?

South Korea's Ministry of Science and ICT held the annual meeting of its Quantum Science and Technology Flagship Project on Tuesday, 10 November 2026, at Hotel Onoma in Daejeon, and used it to report the project's first-year results. The flagship project is the government's large-scale programme for building home-grown quantum technology, running from 2025 to 2029 with about 360.4 billion won (around $266 million) of funding across 26 tasks: seven in quantum computing, six in quantum communication and thirteen in quantum sensing. Research under the programme began in October 2025.

The headline result is in quantum computing. Researchers extended the coherence time of superconducting qubits — the time a qubit can hold its quantum information — to more than 100 microseconds, roughly double the 50-microsecond target set for 2027. They also confirmed about 99% accuracy for entangling operations between two qubits, a core step in any quantum computation and a key measure of how much error a processor introduces.

The timing fits a busy month for Korean quantum computing. Just last week, Yonsei University began operating IBM's next-generation Nighthawk r2 processor at its Songdo campus, and earlier in November South Korea switched on Hangang, its sixth national supercomputer, which is designed to run quantum circuits alongside classical workloads from May 2027. The flagship project's results are the home-grown side of that same push.

South Korea quantum computer 100 microseconds explained: the key numbers

Here are the figures the ministry reported, with the context that makes each one meaningful.

Result	What was reported	Why it matters
Qubit coherence time	More than 100 microseconds	Double the 50-microsecond target set for 2027
Two-qubit entangling accuracy	About 99%	Fewer errors per operation; the foundation for error correction
Flagship project funding	About ₩360.4 billion (~$266 million), 2025–2029	26 tasks: 7 computing, 6 communication, 13 sensing
Next milestone	Error-corrected 100-qubit-class superconducting processor by 2029	The step from lab results to a usable machine
Quantum communication	Solid-state and all-photon quantum repeaters; patents filed	Building blocks for long-distance quantum networks
Quantum sensing	Compact diamond-based heart magnetic-field sensor	Works at room temperature; aimed at heart-disease diagnosis

Why coherence time is the number that matters

A qubit is useful only while it holds its quantum state. The moment it loses that state — a process called decoherence — the calculation it was part of is corrupted. Coherence time is simply how long a qubit survives before that happens, and every operation in a quantum programme must fit inside that window. A longer coherence time means a processor can run more operations, and more complex ones, before errors pile up.

That is why doubling the target a year early is significant, and also why it is not the whole story. Coherence is one of three numbers that decide whether a quantum computer works: the others are how accurately each operation runs (here, about 99% for two-qubit operations) and how many qubits the machine has. South Korea's researchers improved the first two; the third — scaling up to 100 error-corrected qubits by 2029 — is the hard part that remains, and it is the goal the ministry has now set publicly. For comparison, Diraq's silicon-spin quantum computer, now running inside a data centre, operates with eight qubits and targets 256 in the same system within a year — a reminder that every quantum programme is racing the same scaling problem from a different starting point.

It is also worth keeping the scale in mind. One hundred microseconds is one ten-thousandth of a second — an eyeblink is about a thousand times longer. Quantum computers work in these tiny windows because their qubits must be kept colder than outer space, and even then the environment constantly tries to disturb them. The achievement is not that 100 microseconds is a long time in human terms; it is that it is long enough, relative to how fast quantum operations run, to do meaningfully more work per qubit.

Quantum repeaters and the diamond heart sensor

The meeting's other two results show the programme is broader than processors. In quantum communication, researchers developed two kinds of quantum repeater — devices that extend how far quantum entanglement can be shared, which is what a future quantum internet needs. One is a solid-state repeater that generates entanglement on demand; the other is an all-photon repeater that connects entanglement using light. Patent applications have been filed for both.

Diamond with nitrogen-vacancy centres, the defect used in South Korea's quantum heart sensor

Illustrative image: a diamond with a high concentration of nitrogen-vacancy centres. Image: Wikimedia Commons / Lillian B. Hughes et al., CC BY 4.0

In quantum sensing, the team unveiled a compact sensor that measures the extremely faint magnetic fields produced by the heart's electrical activity, using nitrogen-vacancy centres — microscopic defects inside diamonds — to detect them. The sensor works at room temperature, which matters because it removes the bulky cooling that older magnetic sensors need, and the aim is equipment for diagnosing heart disease. Quantum technology, the ministry noted, has been designated one of the "7 SEED" future growth engines, with support now expanding from core research towards building an industrial ecosystem.

Why it matters for Indian readers

For India, the Korean results are a useful benchmark rather than a distant curiosity. India's own National Quantum Mission, approved in 2023 with ₹6,003 crore of funding through 2031, is chasing similar milestones — including building quantum computers in the 50–100 qubit range and developing quantum communication and sensing. South Korea reaching 100 microseconds and 99% two-qubit accuracy a year ahead of its own 2027 target shows what a focused national programme can deliver in its first year, and sets a pace Indian researchers and policymakers will be measuring against.

There is a practical angle too. Quantum sensing is the part of this story most likely to reach ordinary people first: a room-temperature diamond sensor that reads the heart's magnetic field could eventually offer a gentler, cheaper way to screen for heart disease than today's hospital equipment. And the repeater work matters for security — quantum networks are the long-term answer to eavesdropping-proof communication, a concern for banks, governments and telecom networks in India as much as in Korea. IBM's Nighthawk r2 processor in Chicago and RIKEN's five silicon qubits controlled by a single microwave line show the same race running on several tracks at once — superconducting, silicon and trapped-ion machines all chasing the same error-corrected goal.

Should you care?

Verdict: Watch the 2029 goal, not today's numbers. ✅ A 100-microsecond coherence time and 99% two-qubit accuracy are real, verified progress — but they are lab results on the way to a machine, not a machine. The result that would change things is the error-corrected 100-qubit processor South Korea now promises by 2029. If you follow quantum computing, that date is the one to remember; if you follow health tech, the diamond heart sensor is the nearer-term story.

FAQs

What is qubit coherence time?
Coherence time is how long a qubit can hold its quantum state before the environment disturbs it. The longer it is, the more operations a quantum computer can run before errors corrupt the calculation. South Korea's researchers have now pushed it past 100 microseconds for superconducting qubits, double their 2027 target of 50 microseconds.

Why does 100 microseconds matter for quantum computers?
Because every quantum operation must fit inside the coherence window. A longer window means more — and more complex — operations per qubit before decoherence sets in, which is a precondition for error correction and for running useful programmes instead of short demonstrations.

What is South Korea's quantum flagship project?
The Quantum Science and Technology Flagship Project is South Korea's national quantum R&D programme, run by the Ministry of Science and ICT. It invests about 360.4 billion won (around $266 million) from 2025 to 2029 across 26 tasks in quantum computing, communication and sensing, with a goal of an error-corrected 100-qubit-class superconducting processor by 2029.

What is a quantum repeater?
A quantum repeater extends how far quantum entanglement can be shared across a network, in the same way a signal repeater extends a classical network. South Korean researchers reported two designs — a solid-state repeater that creates entanglement on demand and an all-photon repeater that links entanglement using light — with patent applications filed for both.

Takeaway: South Korea's quantum programme has doubled its own 2027 coherence target a year early, hit about 99% two-qubit accuracy, and added a quantum repeater and a diamond heart sensor in the same meeting — a strong first year for a ₩360.4 billion bet. The real test is the 100-qubit error-corrected processor promised by 2029.

Want the wider race in one place? Our Diraq explainer linked above shows how silicon-spin qubits are taking a different route to the same goal.

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