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Comment by dr_dshiv | Hacker News Reader

Useful applications don’t exist. They surely will, at some point, but not yet. That’s why they aren’t provided as examples.

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There are/seem to be very specific scientific applications, mostly around simulation of other systems whose hamiltonians map nicely to that of the computer. For almost everyone on the planet that isn’t very useful, but for that small handful it can be a game changer.

… doesn’t contribute much here, but worth knowing! It’s exciting either way.

Protein folding (computational chemistry), and breaking everyone's crypto.

> breaking everyone's crypto

Symmetric encryption and hash functions with 256 bits are already quantum proof.

Post-quantum algorithms are here in few years. Some of them are already in use in critical applications.

Importantly, Bitcoin and Ethereum are (inadvertently) almost quantum-proof (because the addresses are hashes of the public keys), just not quite (because the public keys still get exposed during transactions). But at least the latter should be fixable (because the community is quite used to changes to the protocol anyway).

I have to object, while not many algorithms exists, one of the most famous ones, Grovers algorithm [0] is also one of the most general ones and quite powerful. It reduces search of 2^n items to about 2^(n/2) while using n q-bits. Thats just the square root of a classical algorithm.

[0] https://en.wikipedia.org/wiki/Grover%27s_algorithm

of course they exist, we just don't have QCs with enough logical qubits yet.

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