Quantum Supremacy: How the Quantum Computer Revolution Will Change Everything

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I think (hope) that you have missed the point of Sabine’s comment: using a numerical model of a theory to test its predictions against some actual experimental measurements, as in the case of Hulse-Taylor or a huge number of other cases (the detection of gravitational waves, for instance) is an entirely different thing than ‘testing’ a theory for which no experimental evidence exists using a numerical simulation. Not once in the book has Kaku even mentioned the intellectual tools (e.g., looking at actual quantum algorithms like Grover’s algorithm or phase estimation, and their performance on various tasks) that would be needed to distinguish 1 from 2. How? The main thing to understand is that quantum computers can make calculations much, much faster than digital ones. They do this using qubits, the quantum equivalent of bits – the zeros and ones that convey information in a conventional computer. Whereas bits are stored as electrical charges in transistors etched on to silicon chips, qubits are represented by properties of particles, for example, the angular momentum of an electron. Qubits’ superior firepower comes about because the laws of classical physics do not apply in the strange subatomic world, allowing them to take any value between zero and one, and enabling a mysterious process called quantum entanglement, which Einstein famously called spukhafte Fernwirkung or “spooky action at a distance”. Kaku makes valiant efforts to explain these mechanisms in his book, but it’s essentially impossible for a layperson to fully grasp. As the science communicator Sabine Hossenfelder puts it in one of her wildly popular YouTube videos on the subject: “When we write about quantum mechanics, we’re faced with the task of converting mathematical expressions into language. And regardless of which language we use, English, German, Chinese or whatever, our language didn’t evolve to describe quantum behaviour.” That mind-blowing future is the focus of the final five or so hours of the audiobook, which explores the real-world impacts quantum computing could have: altering our immune systems to avoid cancer and Alzheimer’s, increasing crop yields, ending world hunger. As Kaku puts it, “the familiar laws of common sense are routinely violated at the atomic level”; but his lucid prose and thought process make abundant sense of this technological turning point. Alternately admiring and critical, unvarnished, and a closely detailed account of a troubled innovator.

Researchers have made great progress in developing the algorithms that quantum computers will use. But the devices themselves still need a lot more work. At this stage, it’s worth introducing an important caveat. Quantum computers are very, very hard to make. Because they rely on tiny particles that are extremely sensitive to any kind of disturbance, most can only run at temperatures close to absolute zero, where everything slows down and there’s minimal environmental “noise”. That is, as you would expect, quite difficult to arrange. So far, the most advanced quantum computer in the world, IBM’s Osprey, has 433 qubits. This might not sound like much, but as the company points out “the number of classical bits that would be necessary to represent a state on the Osprey processor far exceeds the total number of atoms in the known universe”. What they don’t say is that it only works for about 70 to 80 millionths of a second before being overwhelmed by noise. Not only that, but the calculations it can make have very limited applications. As Kaku himself notes: “A workable quantum computer that can solve real-world problems is still many years in the future.” Some physicists, such as Mikhail Dyakonov at the University of Montpellier, believe the technical challenges mean the chances of a quantum computer “that could compete with your laptop” ever being built are pretty much zero. on Friday, May 19th, 2023 at 5:15 am and is filed under Quantum, Rage Against Doofosity, Speaking Truth to Parallelism. Maybe he should have let ChatGPT write it? Something entirely different, could you comment on this paper, pretty please I have found Michio Kaki’s writing to be full of misconceptions for years. He does not represent science well. Maybe he thinks that he is popularising the wonder of science, but he gets so much basic stuff wrong. He is more of a media personality than a scientist I think.Besides that, I think it would be good if journalists writing about this stuff would just ask people making such claims “and then what?”. I mean, let’s assume for a moment we actually manage to build a 7000 logical qubit quantum computer and actually simulate Maldacena’s whatever model on it. And then what? They’ll write papers and press releases. And then what? What will we learn from it? What will we do with it? Cryptography will be another key application. Right now, a lot of encryption systems rely on the difficulty of breaking down large numbers into prime numbers. This is called factoring, and for classical computers, it’s slow, expensive and impractical. But quantum computers can do it easily. And that could put our data at risk. They’re powerful, but not reliable. That means that for now, claims of quantum supremacy have to be taken with a pinch of salt. In October 2019, Google published a paper suggesting it had achieved quantum supremacy – the point at which a quantum computer can outperform a classical computer. But its rivals disputed the claim – IBM said Google had not tapped into the full power of modern supercomputers.

I am just reading a book about Ronald Reagan’s “Star Wars” Strategic Defense Initiative program. It is horrifying how far Edward Teller was able to convince the President, Congress, Pentagon and the public into his hare-brained visions ( “Brilliant Pebbles”, “Excalibur”, and so on). Pure monomaniacal intensity can bring in billions.

What is quantum computing?

A warts-and-all portrait of the famed techno-entrepreneur—and the warts are nearly beyond counting. This is a double howler: first, trial division takes only ~√N time; Kaku has confused N itself with its number of digits, ~log 2N. Second, he seems unaware that much better classical factoring algorithms, like the Number Field Sieve, have been known for decades, even though those algorithms play a central role in codebreaking and in any discussion of where the quantum/classical crossover might happen.