IBM and researchers at the University of Chicago said they successfully completed a verifiable quantum computation using 70 logical qubits, a task difficult for classical computers. The result is seen as an important advance in fault-tolerant quantum computing because it demonstrated not only performance but also the reliability of the computed results.

CoinPost, a blockchain media outlet, reported on Thursday that the joint IBM and University of Chicago team applied a new error-correction technique to complete the quantum computation in about 15 minutes.

The key to the achievement is not simply that it carried out large-scale computation, but that it also presented a way to verify the results. Quantum advantage generally means a quantum computer demonstrating superior computing power to a classical computer, but verifying the accuracy of results has been seen as the biggest technical challenge so far.

The researchers applied a new verification method that improves on Random Circuit Sampling, an existing performance evaluation approach. The method is designed to detect errors during computation while maintaining computational complexity that is difficult for classical computers to reproduce.

The experiment used logical qubits with error-correction capabilities. Logical qubits bundle multiple physical qubits into one to correct errors, providing higher computational stability than physical qubits, which are highly affected by the external environment.

In the experiment, the team performed 2,415 logical two-qubit operations and 468 logical T-gate operations. T-gates are seen as a core operation needed to implement complex quantum algorithms. The results showed the logical error rate fell to about one-tenth of the physical error rate.

Bill Fefferman (빌 페퍼먼), an associate professor at the University of Chicago, explained the significance of the study, saying, "One of the most difficult tasks in demonstrating quantum advantage was verifying the results."

Sumik Ghosh (수믹 고시), a doctoral student researcher at the same university, said advances in verification technology could accelerate the practical use of next-generation fault-tolerant quantum computers. Jay Gambetta (제이 감베타), a director at IBM Research, also stressed the achievement, saying, "We have moved one step closer to the era of quantum advantage."

Still, some assessments say the research does not immediately reach a level that threatens cryptocurrency security systems. Bitcoin uses an elliptic curve cryptography-based public-key encryption method, and the possibility of decrypting it has been raised consistently if sufficiently powerful fault-tolerant quantum computers emerge.

However, research published by Google Quantum AI in March analyzed that about 1,200 to 1,500 fault-tolerant logical qubits would be needed to decrypt Bitcoin encryption. The experiment used 70 logical qubits, leaving a significant gap from the level that would threaten real-world cryptographic systems.

The market views the achievement less as an event that directly affects the cryptographic systems of Bitcoin or Ethereum than as a milestone showing that error-correction-based quantum computing is entering stages of real computation and verification. In particular, implementing technology that can verify computed results is seen as a key foundation for developing large-scale fault-tolerant quantum computers.

IBM has presented a goal through its current roadmap to implement a large-scale fault-tolerant quantum computer by 2029. To that end, it is pushing to develop a system that can handle about 200 logical qubits and quantum operations on the order of 100 million.

As a result, market attention is expected to focus on whether growth in the number of logical qubits and improvements in error rates will continue in line with IBM's development schedule, and how quickly verifiable quantum computation technology will advance into actual commercialization stages.