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. 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. Quantum simulation speeding up progress in biochemistry, high-temperature superconductivity, and the like is at least plausible—though very far from guaranteed, since one has to beat the cleverest classical approaches that can be designed for the same problems (a point that Kaku nowhere grapples with). His book about QFT isn’t half bad, it doesn’t add anything to the Weinberg or Zee but has a very interesting historical foray into simmetries and all the work in the post war era, citing the japanese effort that i knew nothing about. An exhilarating guide to the astonishing future of quantum computing, from the international bestselling physicist

As for his nonsense about quantum computing, there’s so much promotional bullshit going on that it’s understandable that anyone wanting to do something about this has no particular reason to start with Kaku. I know that there is a LOT of hype and inaccurate information in pop Sci books and science magazines, but Kaku seems to be responsible for a disproportionately large share of the garbage! Recently, Google claimed that it had achieved quantum supremacy – the first time a quantum computer has outperformed a traditional one. But what is quantum computing? And how does it work? What is quantum computing?

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This pretty conclusively shows that the explanation for the Kaku phenomenon is simply that he has no idea what he is talking about. Out of interest, why is there no public effort by physicists to counter the relentless nonsense coming from Kaku? Well, that’s the universal law of technology, that [it] can be used for good or evil. When humans discovered the bow and arrow, we could use that to bring down game and feed people in our tribe. But of course, the bow and arrow can also be used against our enemies.” Researchers have made great progress in developing the algorithms that quantum computers will use. But the devices themselves still need a lot more work. I am not sure what Feynman thought quantum computers could do, but they gain you no formal power over classical machines: any problem which can be solved with a quantum computer can be solved with a classical computer, and vice versa. What they do gain is an improvement in time complexity for some problems. That in practice makes some problems soluble which would not be soluble on a classical machine because they have some awful time complexity.

Nothing about Deser just because I never met him and know little about his work. Part of the problem is that I’ve always shared Sidney Coleman’s view on supergravity. 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? The danger to the field of quantum computing is from people like Michio Kaku, getting huge audiences for absurd claims at Joe Rogan. There’s already a lot of discussion of a possible coming “quantum winter”, with the hype hitting the wall of the reality of slow progress.I’ve never heard of Kaku, perhaps because the days of roaming through a bookstore looking at the popular science shelves have passed. Based on your review, I strongly suspect that Kaku asked ChatGPT to write it. Quantum computers aren’t just about doing things faster or more efficiently. They’ll let us do things that we couldn’t even have dreamed of without them. Things that even the best supercomputer just isn’t capable of.

We’re hearing this week from two very different parts of the string theory community that quantum supremacy (quantum computers doing better than classical computers) is the answer to the challenges the subject has faced.Knox #1: As a test, I tried asking GPT-4 to write a quantum computing explainer in the style of Michio Kaku, and it indeed generated similar prose with similar misconceptions. But then I asked it to write it in the style of Scott Aaronson and it did the same… 😀 Most of the big breakthroughs so far have been in controlled settings, or using problems that we already know the answer to. In any case, reaching quantum supremacy doesn’t mean quantum computers are actually ready to do anything useful. If you ask a normal computer to figure its way out of a maze, it will try every single branch in turn, ruling them all out individually until it finds the right one. A quantum computer can go down every path of the maze at once. It can hold uncertainty in its head. 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.” Thank you. Physicists are unusually polite group of people. The way you detect someone is not worth listening is the deafening silence around them from their peers. A good advice with cranks, but when money, government or the public is involved, someone should say something. Kaku is just cynically making money.

Maybe he should have let ChatGPT write it? Something entirely different, could you comment on this paper, pretty please You’ll probably never have a quantum chip in your laptop or smartphone. There’s not going to be an iPhone Q. Quantum computers have been theorised about for decades, but the reason it’s taken so long for them to arrive is that they’re incredibly sensitive to interference.

The other thing that qubits can do is called entanglement. Normally, if you flip two coins, the result of one coin toss has no bearing on the result of the other one. They’re independent. In entanglement, two particles are linked together, even if they’re physically separate. If one comes up heads, the other one will also be heads. 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. 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.