Related: "Quantum computing worst case scenario: we are Lovelace and Babbage" [1] For scale: Babbage's planned analytical engine had a word size of 50 digits,

Related: "Quantum computing worst case scenario: we are Lovelace and Babbage" [1] For scale: Babbage's planned analytical engine had a word size of 50 digits, a clock rate of 7Hz, and a physical size of roughly a locomotive [2]. Contrast [3] where it's estimated that 600-digit superposed additions would run at 27Hz (by dedicating millions of qubits to magic state distillation of the underlying AND gates). Given current plans, a quantum computer capable of doing arithmetic operations as wide and as fast as the analytical engine would probably be larger than the analytical engine. We can see how to do reliable quantum computation in principle. The overhead of error correction makes it daunting in scale. It sure would be nice if someone came along and invented the quantum computing equivalent of a vacuum tube or a transistor. [1]: https://csferrie.medium.com/quantum-computing-worst-case-scenario-we-are-lovelace-and-babbage-1e3005d677e6 https://csferrie.medium.com/quantum-computing-worst-case-sce... [2]: https://medium.com/tech-is-a-tool/building-the-modern-computer-babbages-analytical-engine-8179dedb08c8 https://medium.com/tech-is-a-tool/building-the-modern-comput... [3] "How to factor 2048 bit RSA integers in 8 hours using 20 million noisy qubits" https://quantum-journal.org/papers/q-2021-04-15-433/ https://quantum-journal.org/papers/q-2021-04-15-433/