Experts answer the question: 'Is practical quantum computing on the horizon?'
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https://scottaaronson.blog/?p=9425
In December 2025, Aaronson attended the Q2B International Conference on Quantum Technology held in Santa Clara, California, and gave a keynote speech titled 'Why I Think Quantum Computing Works.' This keynote speech, which spoke about the practical application of quantum computing, was one of the most optimistic speeches Aaronson has ever given.
While Aaronson has often spoken about the challenges of accelerating quantum computing, he focused his keynote speech on the experimental milestones achieved over the past year, each of which weakened any doubts about scalable quantum computing.
After returning from Q2B, Aaronson appeared on a podcast on the quantum computer-related YouTube channel The Quantum Bull titled 'How Close Are We to Fault-Tolerant Quantum Computing ?'
Scott Aaronson on the Possibility of Fault-Tolerant Quantum Computing by 2028 - YouTube
In this podcast, Aaronson discusses a variety of topics, focusing on the quantum computing race.
The technical challenges of quantum computing are being resolved
Large companies and startups entering the quantum computing field are at least working to solve real-world technical challenges, regardless of whether they will achieve commercial success, and some companies are making astonishing progress. Meanwhile, others are focused on selling investors and governments the story that quantum computing will revolutionize machine learning and finance. Aaronson also criticized quantum computing company IonQ for misleading governments into believing that quantum computers, unlike AI, are deterministic and therefore do not produce hallucinations.
◆The most impressive demonstration of the past year
Aaronson cited some of the most impressive demonstrations over the past year as ' ion traps by Quantinuum and Oxford Ionics ,' ' superconducting qubits by Google and IBM,' and ' neutral atom quantum computers by QuEra , Infleqtion , Atom Computing , and others.'
◆2025 exceeded expectations in terms of hardware
The quantum computing field in 2025 met or exceeded Aaronson's expectations for hardware, with multiple platforms achieving two-qubit gates with over 99.9% fidelity and exceeding theoretical thresholds for fault tolerance. This has led Aaronson to take companies' roadmaps of future goals more seriously.
◆Quantum computer applications
The main applications of quantum computers remain largely unchanged from a quarter century ago: simulating quantum physics and chemistry, cracking widely used cryptography, and ultimately providing certain advantages in machine learning and optimization. While the discovery of new quantum algorithms is expected to expand these applications, it is also possible that some quantum algorithms will be dequantized.
Quantum computing is a hot field, but not all breakthroughs or achievements are necessarily made public. For example, in March 1940, British physicists Otto Frisch and Rudolf Peierls estimated the mass of uranium-235 needed for a nuclear bomb. However, because publishing their results in an academic journal could have encouraged enemy nations to build nuclear bombs, they chose not to make them public and communicated them only through military channels.
Similarly, researchers who estimate the number of physical qubits and gates required to crack operational cryptosystems may eventually stop publishing their estimates to prevent the world's cryptosystems from being cracked. 'We may already be past that point,' Aaronson said. 'This is the clearest public warning we can provide today about the urgency of the transition to post-quantum cryptosystems. I'm grateful that this transition process has already begun.'
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