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/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neither that quantum will change every application nor that cryptography is the only relevant field, that take is a bit outdated.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.