# Why Quantum Computers might never work Source: https://www.youtube.com/watch?v=WeVGJr6h-CQ Recap page: https://rapidrecap.app/video/WeVGJr6h-CQ Generated: 2025-12-31T16:34:49.875+00:00 --- ## Quick Overview Quantum computers might never achieve the promised computational advantage because noise inherent in quantum mechanics, as argued by physicists like Gil Kalai, Robert Alicki, Gerard 't Hooft, and Tim Palmer, fundamentally limits their capability, preventing them from reliably factoring large numbers or performing complex calculations beyond what classical computers can achieve. **Key Points:** - A minority of physicists, including Gil Kalai, argue that quantum computers will never deliver on the promised investment returns because they cannot fundamentally work. - Gil Kalai's argument suggests that the required level of precision to overcome noise (like from neutrinos or gravitational waves) is impossible for quantum computers to maintain. - Robert Alicki argues that if quantum computers model noise realistically (like the Continuous Spontaneous Localization model), factoring numbers with millions of digits remains impossible. - Gerard 't Hooft believes that the underlying physics preventing quantum computers from factoring large numbers implies quantum mechanics itself might not be fundamental, suggesting the collapse model is a real physical process. - Tim Palmer estimates that even with significant error correction, useful quantum computation requires fewer than 1,000 logical qubits, far short of what is often advertised, and suggests that fault-tolerant quantum computation is severely limited. - The video contrasts the quantum model (atom) with the non-quantum model (solar system) to illustrate the difference between classical and quantum physics rules. - The sponsor, Brilliant, offers interactive courses in Math Foundations, Data Analysis, Programming & CS, and Science, with a 20% discount on annual premiums using the provided link. ![Screenshot at 00:07: The title slide 'Quantum Computing Skepticism' appears, setting the context for the video which challenges the claims of quantum computing supremacy.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-00-07.jpg) **Context:** This video presents a skeptical viewpoint on the feasibility and projected utility of quantum computing, focusing on arguments from several theoretical physicists who question whether current quantum models can overcome fundamental physical limitations like noise and decoherence to achieve true quantum advantage over classical computers. The presenter, Sabine Hossenfelder, reviews the papers and arguments put forth by these critics, contrasting their theoretical limitations against the often optimistic claims made by quantum computing proponents. ## Detailed Analysis The video explores the arguments of physicists who express skepticism about quantum computers achieving practical, world-changing superiority over classical machines. Sabine Hossenfelder highlights the claims of a small group of scientists who believe quantum computers will never deliver on the promises of massive speedup. Gil Kalai argues that the inherent noise in nature—including from neutrinos and gravitational waves—will prevent quantum computers from achieving the necessary precision, making large-scale factoring impossible. Robert Alicki's work on the Continuous Spontaneous Localization (CSL) model suggests that factoring numbers with millions of digits remains impossible unless classical algorithms fundamentally improve. Gerard 't Hooft also suggests that quantum mechanics is not fundamental, supporting the idea that wave function collapse is a real physical process. Tim Palmer estimates that even with error correction, useful quantum computers might be limited to fewer than 1,000 logical qubits, putting practical applications far into the future. The video contrasts the quantum mechanical description (atom with probabilistic electron locations) against the classical description (solar system with defined orbits) to illustrate the core difference in underlying physics that leads to these limitations. The presentation concludes by promoting Brilliant's interactive math and science courses as a way to improve problem-solving skills. ### Introduction to Skepticism - Physicists don't like to talk about quantum computers that might never properly work because we don't understand quantum physics - A small minority hold this view - The premise is that quantum computers won't deliver on investment because they can't work. ### Skeptical Arguments - Gil Kalai & Robert Alicki - Kalai argues that quantum computers must have inescapable noise due to fundamental quantum mechanics, preventing them from achieving advantage over classical computers (02:09, 02:12) - Alicki's work suggests that if noise models (like CSL) are realistic, factoring large numbers will be impossible (02:23, 02:40). ### Skeptical Arguments - Gerard 't Hooft & Tim Palmer - 't Hooft argues that quantum mechanics is not fundamental and believes in step-by-step mechanisms like spontaneous localization (03:30, 03:34) - Palmer estimates that useful quantum computers require less than 1000 logical qubits, suggesting current computational miracle claims are false (03:43, 03:52). ### The Role of Noise and Collapse - The CSL model suggests noise causes decoherence and limits practical quantum computation to less than 1,000,000 physical qubits (04:27, 04:33) - The collapse model is presented as a real physical process, not just a mathematical trick (04:16, 04:21). ### Conclusion and Sponsor Plug - The video ends with a celebratory New Year's graphic (05:35) and encourages viewers to try Brilliant courses for improving problem-solving skills, offering a 20% discount (05:58, 06:38). ![Screenshot at 00:07: The title card 'Quantum Computing Skepticism' sets the theme of the segment.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-00-07.jpg) ![Screenshot at 00:26: A physical representation of a quantum computer, likely Google's Sycamore processor setup, emphasizing the hardware complexity.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-00-26.jpg) ![Screenshot at 00:38: An animation illustrating 'Entanglement' using Bloch spheres alongside the quantum computer hardware, representing the core mechanism being questioned.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-00-38.jpg) ![Screenshot at 01:35: The text overlay 'Untested Territory' highlights the theoretical uncertainty surrounding the scalability of quantum mechanics principles to large systems.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-01-35.jpg) ![Screenshot at 03:08: The Schrödinger equation \($H\|\\Psi\\rangle = i\\hbar\\partial\_t\|\\Psi\\rangle$\) is displayed with the text 'Not Fundamental', representing the theoretical basis some skeptics question.](https://ss.rapidrecap.app/screens/WeVGJr6h-CQ/00-03-08.jpg)