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A Vacuous Quantum Calculation, Chinese Lasers, Shopping Bots, and Cosmohedra
This week’s science bits from SWTG
Sabine Hossenfelder
February 12, 2025
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Quantum Computer Simulates End of Universe
Image: D-Wave’s Quantum Annealer. Credit: D-Wave
Physicists have used a D-Wave quantum computer with 5564 qubits to simulate how our universe might one day fall apart. Estimates currently indicate that the vacuum that surrounds us has a very long half-life of 10^500 years or so (give or take a few billion years) but will eventually decay to a state of lower energy. Because vacuum states should be stable, physicists call the current, long-lived but ultimately unstable state a “false vacuum” and its demise a “false vacuum decay.”
This false vacuum decay is a quantum process that has no good analogies in nature, but its rudimentary features such as the nucleation and spread of bubbles can be simulated with a quantum computer. I’m not sure what they learned from it other than that it decays as expected but we can now unironically say that D-wave is working on the end of the universe.
D-Wave’s approach differs from that of most other quantum computing companies in that they do not use universal quantum computers that could perform generic quantum algorithms. They instead work with quantum annealers that, if suitability initialized, naturally solve certain optimization problems. Personally, I think it’s fair to also call this a quantum computation, but some of my colleagues object.
This week’s episode of Science News is about the wave-function of the universe. You see, physicists think that our universe started out as just a lot of quantum fluctuations. That means, if you’re able to calculate wave-function of those quantum fluctuations, you can learn how the universe ended up the way it is now. In a pre-print, a group of physicists around Nima Arkani-Hamed say they’ve worked out a new powerful method to calculate the wave function of the early universe, and they’re calling it the “cosmohedra.” Let’s take a look. This week’s video also comes with a quiz, which you can take here.
Speaking of quizzes, you can now create and share your own quizzes on QuizWithIt for free! Just set up an account and creator profile and you’re good to go. You can create quizzes for websites, videos, blogposts, podcasts, or just for fun, and your audience can support you by subscribing to your content — which allows them to collect points by taking your quizzes. Each quiz has a unique URL, can be embedded into websites or newsletter, and be shared on social media. Plus, we’re constantly fixing bugs to improve the user experience. Happy quizzing!
Satellite Images Reveal New Laser-Fusion Facility in China
Image: Planet Labs
Satellite images from the American company Planet Labs have revealed that China is building a laser-fusion facility similar to the National Ignition Facility (NIF) in the United States – but 50% larger. The NIF made international headlines in 2022 for reaching nuclear ignition in a hydrogen-filled target that they shot at with lasers.
This method, called “inertial confinement,” is one of the avenues to create energy from nuclear fusion but it is difficult to create net energy with it because lasers tend to be very energy inefficient. My back-of-the-envelope estimate says that the NIF put at least 100 times more energy into the laser shots than they got out of the nuclear fusion. The same technology, however, can also be used to test implosions and explosions at the highest precision, delivering data that is useful in the construction of nuclear warheads. More on Reuters.
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Bots Buy All New Nvidia Graphic Cards
The magazine PC Games Hardware reports that the new Nvidia graphic cards GeForce RTX 5090 and 5080 FE were sold out before they became officially available for sale on 30 January 2025. They traced back the early purchases to a bot operating from a discord server. New startup idea: A robot that queues for you. More here.
I’ll be doing a monthly podcast with Lawrence M. Krauss on Origins called “What's New in Science.” It’s an exciting new segment on science in the news, what's hype, what's true, and what's interesting. The first episode is out now!
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