Have you been feeling anxious about technology lately? If so, you’re in good company. The United Nations has urged all governments to implement a set of rules designed to rein in artificial intelligence. An open letter, signed by such luminaries as Yuval Noah Harari and Elon Musk, called for research into the most advanced AI to be paused and measures taken to ensure it remains “safe … trustworthy, and loyal”. These pangs followed the launch last year of ChatGPT, a chatbot that can write you an essay on Milton as easily as it can generate a recipe for everything you happen to have in your cupboard that evening. 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 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. Estimates that I have seen say it’ll require about a million physical qubits for 110 to 150 or so logical qubits, though that depends on error rate and algorithm. I strongly doubt that you can do 7000 logical with only 1 million physical ones, it’s almost certainly considerably more. At the very least I’d like to see a source for the NS estimate. 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.

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. And then there’s the Misconception of Misconceptions, about how a QC “analyzes all possible paths at the same time”—with no recognition anywhere of the central difficulty, the thing that makes a QC enormously weaker than an exponentially parallel classical computer, but is also the new and interesting part, namely that you only get to see a single, random outcome when you measure, with its probability given by the Born rule. That’s the error so common that I warn against it right below the title of my blog.

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. 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. 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. Scott Aaronson has read the book and confirms that it’s every bit as awful as it seems. For a different look at out-of-control quantum […] 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.

Because Teller (in Livermore) was able to bring in funding, Livermore’s director refused to rein him in and even prevented other scientists writing corrective letters. Competing labs–Argonne and Los Alamos–had to conduct their own tests to show that proposals don’t work and Teller just came up even more insane plans. Update: Michio Kaku was on a very recent Joe Rogan Experience, getting a huge audience for his explanations of quantum computing. Some commentary here. There are other reasons, as well. From an early age, Kaku was, unsurprisingly, a science fiction nut. But he wasn’t content to simply swallow the stories, and wanted to know if they were really possible, whether the laws of physics might verify or contradict them. “And in the science section, there was nothing, absolutely nothing. And I was [also] fascinated by Einstein’s dream of a theory of everything, a unified field theory. Again I found nothing, not a single book, on Einstein’s great dream. And I said to myself, when I grow up, and I become a theoretical physicist, I want to write papers on this subject. But I also want to write for myself as a child, going to the library and being so frustrated that there was nothing for me to read. And that’s what I do.” 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? While we’re on the subject of Stanley Deser, I’ll mention that World Scientific is providing free access to his autobiography, _Forks in the Road_, until July 31 of this year:That’s a good question, one I’ve asked people over the years. On the string theory front, Kaku has been writing misleading popular books on the topic for over 35 years. Most string theorists agree, at least privately, that what he writes and says has become increasingly inaccurate and increasingly embarrassing. They generally however make the argument: “dealing with this is not my responsibility, there’s loads of misleading stuff out there about science. And, maybe it will have a positive effect, getting young people and the public interested in this kind of science, going on to read better books.” A cynical point of view on this would be that you can’t expect people to go out of their way to challenge something untrue which is promoting their own interests. When it gets to the point of damaging their interests, they might do something and we’re not there yet. The runaway success of the microchip processor may be nearing its end, with profound implications for our economy, society and way of life, even leaving Silicon Valley as a new Rust Belt, its technology obsolete. Step forward the quantum computer, which harnesses the power and complexity of the atomic realm, and may be useful in solving humanity's greatest challenges from climate change, to global starvation, to incurable diseases. Humanity's next great technological achievement already promises to be every bit as revolutionary as the transistor and microchip once were. Its unprecedented gains in computing power and unique ability to simulate the physical universe herald advances that could change every aspect of our lives. President Joe Biden inspects a quantum computer at an IBM facility in New York state, October 2022. Photograph: Andrew Harnik/AP