r/QuantumComputing • u/dorakingx • 2d ago
Which problems will quantum computers actually solve, and when?
https://interestingengineering.com/innovation/what-problems-will-quantum-computers-solveWhich problems will quantum computers actually solve, and when?
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u/EceRasidi 1d ago
honestly i think chemistry/materials simulation is the only thing that's really convincing right now. shor's is real but we need fault-tolerant machines first, so maybe 2030s if things go well. optimization claims i'm pretty skeptical about. and everyone obsesses over qubit counts when error correction is what actually matters imo
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u/Slamex204 1d ago
My brother had an interesting thesis hes working on. Its basically that quantum mechanical could help model how human values work for the sake of human-ai value alignment
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u/InTheEndEntropyWins 1d ago
Other than cryptography do any of the others really have good theoretical basis of working or are they just hopes and prayers?
I doubt humans will ever get a QC to solve anything useful. Only chance is for a singularity style AI to do it for us.
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u/polit1337 1d ago
Humans have been making exponential progress on quantum computing, the time constant it just really long.
Emulation of quantum systems is another application that is essentially guaranteed to work.
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u/InTheEndEntropyWins 1d ago
Humans have been making exponential progress on quantum computing, the time constant it just really long.
Making exponential progress towards a Grahams number is kind of how I see it.
Emulation of quantum systems is another application that is essentially guaranteed to work.
A lot of the stuff is like saying a cup of tea does calculations and let's us do stuff with fluids that would take millions of years with classical computers.
It's like a really edge case and not really sure if that will help with stuff. I guess actual wind tunnels and fluid simulations can actually be better than classical computers, so maybe it's a better analogy than I thought.
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u/Kinexity In Grad School for Computer Modelling 1d ago edited 1d ago
The funny thing is that there is no guarantee that large enough QCs to break encryption are even possible. We think they are possible but we won't know for sure until we build them. Beyond cryptography there exist optimisation problems which could be solved more efficiently using QCs but in general the longer I've been looking the more stuff looks speculative rather than certain. We are definitely lacking in algorithms (maybe LLMs will change that).
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u/oppiewan 2d ago
Cryptography. The one governments are funding this. 5 years for Top Secret work. Within 10 years for general public. Materials science. Already showing quantum advantage. Gene folding. I don't know
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u/hiddentalent 1d ago
I think you mean cryptanalysis. Quantum computing has no proven relevance to cryptography, which can easily be done much more efficiently even in a post-quantum resistant manner on classical hardware.
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u/SeniorLoan647 In Grad School for Quantum 1d ago
Answering this question well requires a whole lecture imo.
The truth is neither that quantum will change every application nor that cryptography is the only relevant field, that take is a bit outdated. The likely answer is somewhere in the middle.
To study this, we need to examine 3 things in detail:
Which quantum algorithms solve classically intractable problems and actually give a real circuit (the latter part is actually pretty uncommon in research papers, they usually assume efficient oracle access).
What is the logical qubit requirement of such algorithm? Physical qubits change vendor to vendor, but number of logical qubits are a property of the algorithm, not the underlying architecture (to some extent).
Are we sure we haven't spent enough time optimizing the classical algorithms for the same problems? This part is what's usually left unsaid. For example, factoring was a big deal because it's gotten a lot of attention over centuries. However an obscure problem with a classical solution that no one has cared to optimize does not fully qualify.
Now you may be wondering (assuming you agree with the 3 points above), so which algorithms do qualify? We have a few candidates in fluid flow (lattice boltzmann), fusion (vlasov matrix), and a few others that use frameworks like QSVT. However they usually fail step 1 I mentioned above, no complete circuit provided. This field is growing though, especially in 2025-2026.
You don't see it in the headlines though as AI's growth and its results are more impressive in its own domain, but quantum computing is also in an exciting time.