Harvard researchers hail quantum computing breakthrough with machine that can run for two hours — atomic loss quashed by experimental design, systems that can run forever just 3 years away

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That's an over 55,000% increase in operational time.

Quantum Computer
(Image credit: Getty / Chicago Tribune)

A group of physicists from Harvard and MIT just built a quantum computer that ran continuously for more than two hours. Although it doesn’t sound like much versus regular computers (like servers that run 24/7 for months, if not years), this is a huge breakthrough in quantum computing. As reported by The Harvard Crimson, most current quantum computers run for only a few milliseconds, with record-breaking machines only able to operate for a little over 10 seconds.

Although two hours is still a bit limited, researchers say that the concept behind this could allow future quantum computers to run for much longer, maybe even indefinitely. “There is still a way to go and scale from where we are now,” says research associate Tout T. Wang, “But the roadmap is now clear based on the breakthrough experiments that we’ve done here at Harvard.”

The research team addressed this by developing the “optical lattice conveyor belt” and “optical tweezers” to replace qubits as they’re lost. This system has 3,000 qubits and allows them to inject 300,000 atoms per second into the quantum computer, overcoming the qubit loss. “There’s now fundamentally nothing limiting how long our usual atom and quantum computers can run for,” said Wang. “Even if atoms get lost with a small probability, we can bring fresh atoms in to replace them and not affect the quantum information being stored in the system.”

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Jowi Morales
Jowi Morales
Contributing Writer

Jowi Morales is a tech enthusiast with years of experience working in the industry. He’s been writing with several tech publications since 2021, where he’s been interested in tech hardware and consumer electronics.

7 Comments Comment from the forums
  • Mindstab Thrull
    "Other team members believe that this breakthrough will allow us to have quantum computers that can run forever in about three years. Before this, experts said that it was at least half a decade away, if not longer."

    Half a decade is five years. If this was said two years ago then both are true!

    Just math things :)

    Mindstab Thrull
    Reply
  • JRStern
    most current quantum computers run for only a few milliseconds, with record-breaking machines only able to operate for a little over 10 seconds.
    I did not know that.
    Of course in reality they don't run at all no matter how long or short, but with all the absurd claims, somehow I'd missed this little detail.
    But - does it matter? I thought a single qbit could solve life, the universe, and everything instantly. No?
    Reply
  • sjkpublic
    Would have liked the article to also list the metric of entanglements.
    Reply
  • Sean Hibbitt
    Hey, quantum physicist here. I don't work directly with quantum computers but I know a lot about them, specifically traditionally superconducting ones like Google and IBM.

    I believe this is the research article: https://www.nature.com/articles/s41586-025-09596-6 - I recommend you include links in the future.

    I believe there might have been an critical misunderstanding in this article -ofc I can be wrong. They specify reloading of atoms as qubits, with a reload rate of 30,000 of qubits (initialised ones) per second.

    This is different to coherence time which describes the maximum length of time an algorithm can take before the qubits become classical, i.e, off. Sounds like the maximum coherence time would be 0.1 seconds without some fancy codes —the time it takes to replace all the qubits. It's like replacing all the transistors in a computer everyone 0.1 seconds.

    So that 55,000% increase in operation time i believe mixes up the time they run experiments Vs the maximum individual computation time.
    Reply
  • bit_user
    The article said:
    Although it doesn’t sound like much versus regular computers (like servers that run 24/7 for months, if not years), this is a huge breakthrough in quantum computing. As reported by The Harvard Crimson, most current quantum computers run for only a few milliseconds, with record-breaking machines only able to operate for a little over 10 seconds.
    It's not a good comparison to liken them to conventional computers.

    A better analogy is GPU computing, where it wasn't long ago that your compute tasks needed to complete within a couple seconds, or else the GPU driver would think the GPU was hung and reset it. So, unless the user disabled that time limit, your app had to break down its GPU computation into pieces that would each complete within that amount of time.

    The article said:
    Quantum computing has the potential to change the way we do computing, breaking barriers in cryptography, finance, medicine, and more.
    Eh, it only changes the way we'd approach certain classes of problems. It wouldn't affect the vast majority of computing tasks, which is another reason why personal quantum computers seem unlikely to happen in the foreseeable future.
    Reply
  • bit_user
    Sean Hibbitt said:
    Hey, quantum physicist here.
    Hello! Thanks for contributing!

    Sean Hibbitt said:
    I believe this is the research article: https://www.nature.com/articles/s41586-025-09596-6 - I recommend you include links in the future.
    The author linked an article in Harvard's campus newspaper, The Crimson, as the source. That article mentioned a paper in Nature but also didn't include a link.

    Sean Hibbitt said:
    So that 55,000% increase in operation time i believe mixes up the time they run experiments Vs the maximum individual computation time.
    Ah, makes sense. I had difficulty see how these new atoms could assume the same quantum state as the ones they replaced. If I understand you correctly, they cannot.
    Reply
  • Pocketguy
    bit_user said:
    I had difficulty see how these new atoms could assume the same quantum state as the ones they replaced. If I understand you correctly, they cannot.
    Agreed. There is a "No Cloning" theorem that says the new atoms can't be initialized with a copy of the state of the old atoms because qubits cannot be copied. https://en.wikipedia.org/wiki/No-cloning_theorem (I can cite the theorem but I couldn't describe the proof to you.)
    Reply