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> With all this investment, quantum computing may be coming soon Assuming we double the number of physical qubits we can use in a quantum computer every year s

> With all this investment, quantum computing may be coming soon Assuming we double the number of physical qubits we can use in a quantum computer every year starting now, we might be able to build one capable of running interesting algorithms sometime around 2040. The general consensus in the field is that we need to have 100,000 times more physical qubits in a machine to achieve scalable error-corrected quantum computation. That represents tens of millions of qubits; our current state of the art is floating somewhere in the low to high tens of qubits. That’s quite sobering compared to breathless tech reporting, and it doesn’t address the decoherence reductions we’ll need either. Quantum computing is not coming soon, barring an unlikely and unpredictable series of fundamental breakthroughs. The field is still very much in the, “we have no evidence it’s impossible” stage of research.

Verdex 8y ago
It sounds like the error correction that we need for a lot of "general" purpose quantum functions requires a lot of qubits. However, it also sounds like we can build some special purpose machines using the 50-100 qubit machines that are coming online now. https://www.youtube.com/watch?time_continue=1&v=BvVciA5iXH4 https://www.youtube.com/watch?time_continue=1&v=BvVciA5iXH4 (Contains mention of work that Scott Aaronson did that could be usable with 50ish qubits. Specifically, generating random numbers that we can trust.)
- throwawaymath 8y ago
  Scott Aaronson is a brilliant computer scientist, but I honestly don’t see it. There are a lot of these bizarre “applications” coming from quantum computing theorists or physicists. Generally speaking they read as a little out of touch with whatever field they’re proposing the new thing too. For example, generating random numbers with quantum computers is an interesting theoretical exercise. But it’s completely asinine in practice. The world moved on from information theoretic randomness decades ago because complexity theoretic randomness is basically fine for just about any purpose. It comes across as grasping at straws when you’re proposing using a quantum computer to generate true randomness. Sure, you could, but what a ridiculously overengineered way of getting random bits... For similar reasons, I’m incredibly skeptical of quantum cryptography. Go find someone who publishes at an IACR conference and ask them for their take on quantum key agreement protocols.

Verdex 8y ago

It sounds like the error correction that we need for a lot of "general" purpose quantum functions requires a lot of qubits. However, it also sounds like we can build some special purpose machines using the 50-100 qubit machines that are coming online now. https://www.youtube.com/watch?time_continue=1&v=BvVciA5iXH4 https://www.youtube.com/watch?time_continue=1&v=BvVciA5iXH4 (Contains mention of work that Scott Aaronson did that could be usable with 50ish qubits. Specifically, generating random numbers that we can trust.)

throwawaymath 8y ago
Scott Aaronson is a brilliant computer scientist, but I honestly don’t see it. There are a lot of these bizarre “applications” coming from quantum computing theorists or physicists. Generally speaking they read as a little out of touch with whatever field they’re proposing the new thing too. For example, generating random numbers with quantum computers is an interesting theoretical exercise. But it’s completely asinine in practice. The world moved on from information theoretic randomness decades ago because complexity theoretic randomness is basically fine for just about any purpose. It comes across as grasping at straws when you’re proposing using a quantum computer to generate true randomness. Sure, you could, but what a ridiculously overengineered way of getting random bits... For similar reasons, I’m incredibly skeptical of quantum cryptography. Go find someone who publishes at an IACR conference and ask them for their take on quantum key agreement protocols.