AI-rewritten: This is a summary of an article from Phys.org, rewritten by AI (Qwen, running locally) to make it easier to read. The facts come from the original article – read it for the full story.

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Professor Takuji Miki explains that quantum computers use qubits, which can exist in multiple states at once, unlike conventional bits that are only 0 or 1. This allows them to process many possibilities simultaneously for specific tasks like simulating chemical reactions needed for new medicines or materials. While they cannot speed up every calculation, they excel at prime factorization, a task where breaking large numbers into prime factors is extremely difficult for standard computers but crucial for modern encryption security.

Currently, quantum computers face significant challenges, primarily the high rate of errors during calculations. To fix this, researchers need millions of qubits to perform useful work, though current systems like the one by RIKEN and Fujitsu only have 256. Professor Miki notes that his group uses silicon spin qubits, which can be built with existing semiconductor technology, and estimates that practical quantum computers with around one million qubits could appear between 2035 and 2040.

A major hurdle is cooling these qubits to near absolute zero (-273.15°C) to stop thermal noise from disrupting them. Researchers are developing control circuits that fit inside the cryogenic refrigerator to manage wiring heat, but this requires new semiconductor designs since standard chips fail at such low temperatures. Additionally, quantum computers could break current encryption methods used in communications and military technology, prompting global research into post-quantum cryptography to secure future data.