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nagareteku t1_j1m6fas wrote

Reply to comment by eggybread70 in An IBM Quantum Computer Will Soon Pass the 1,000-Qubit Mark by giuliomagnifico

Simulations and cryptography mainly. It might have potential to reduce time complexity of algorithms from exponential to quasi exponential or even polynomial time (n-bit encryption).

Computations that may take longer than the age of the universe to perform on classical computers can now be approximately computed on quantum computers on a practical time scale of mere months or years.

Quantum computers are however very similar to Field Programmable Gate Arrays. They are specifically designed for one fixed algorithm at a time, but perform extremely well at it.

This means that it will likely be unable to run Far Cry or Crysis, just like how bitcoin miners cant crack your passwords, nor Deep Crack can stream and record 4K video.

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shadowalker125 t1_j1m7r5w wrote

>Quantum computers are however very similar to Field Programmable Gate
Arrays. They are specifically designed for one fixed algorithm at a
time, but perform extremely well at it.

Wouldn't that make it more like an ASIC rather than an FPGA? Or can they be changed?

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nagareteku t1_j1mfh79 wrote

Variables such as temperature of qubits, voltage and time of laser pulses can be changed. The arrangements of specific quantum gates can be varied as well. Unlike an ASIC, quantum computers can be reconfigured from time to time to fit the required algorithm.

For now, quantum computers are far from general-purpose, and even then it will be redelegated into a discrete "QPU" card similar to your GPU for quantum-related computing purposes.

Affordable room temperature and pressure superconductors will need to be mainstream before that happens.

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troyboltonislife t1_j1n1pa7 wrote

will this be used for machine learning at all? can these computers do the linear algebra used in machine learning?

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nagareteku t1_j1nf075 wrote

Nobody knows what would happen in the future, but I would guess that in very niche use cases such as the Travelling Salesman problem (TSP). For classical computers the most commonly used is the Held-Karp algorithm that solves the TSP in just O(n^(2)2^(n)) compared to the naive (n!). The best quantum exact algorithm is Ambaninis algorithm at O(1.728^(n)) found in 2019.

Quantum chips can be used to accelerate machine learning for pathfinding AI that may face the TSP, such as for location app servers and self driving cars.

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noideaman t1_j1ngjvs wrote

Notice, you didn’t reduce complexity to polynomial switching to quantum. We still don’t know if NP-Complete problems can be solved in polynomial time on a quantum computer. If I recall, the top theoreticians think no.

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nicuramar t1_j1nv1yn wrote

Yeah, BQP (the problem class solved by quantum computers) is generally believed to be disjunct from NPC.

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_Asparagus_ t1_j1nkwct wrote

Ambanini's algorithm will almost certainly never be used practically. It relies on Grover search to achieve its speedup, which has been basically shown to not be practical in the foreseeable future (see here for example. Held-Karp isn't used in practice either, since the exponential complexity is detrimental very quickly, and instead heuristics are used (this usually for example what popular software like Gurobi does). So extremely unlikely that TSP will be something quantum will help us with

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_Asparagus_ t1_j1njvo6 wrote

No, it won't. ML applications of anything quantum are extremely limited, especially in this regime of qubit numbers.

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troyboltonislife t1_j1nllvd wrote

I guess I am not fully understanding of what calculations these computers are good for? I guess I thought they would be able to do something like linear algebra (multiplying many numbers together quickly) but it sounds like no

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professorDissociate t1_j1n60ey wrote

I feel like AI will eventually be something that really takes off thanks to QPUs.

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craigularperson t1_j1ncqps wrote

Okay, now explain it to me like I am five?

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nagareteku t1_j1ngso4 wrote

Quantum chips will solve some math problems faster than normal computers. It is unlikely these chips will be used to run computer games.

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BronzeHeart92 t1_j1ptn6m wrote

One can only imagine tho what sorts of games these would have in future...

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Gekokapowco t1_j1ngg4m wrote

Is it like a really fast CPU? Exceedingly fast at doing a single, potentially complex task? Vs a GPU which can do a lot of simple tasks at once?

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km89 t1_j1ohf92 wrote

Sort of, but not really.

It could be faster than classical computers at a specific task, yes.

But it's not just churning through the same steps a classical computer would, faster than a classical computer would. It's something entirely different, which is why the biggest benefit is likely going to be the simulation of systems we can't currently simulate.

So it's not like a really fast CPU, the way a car is a faster vehicle than a horse. It's more like a petting zoo versus a conservation zoo. Some of the same things are present in both, but they really have almost entirely different purposes.

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Extension_Bat_4945 t1_j1nrzrc wrote

What I do wonder tho is, how will all these investment return itself? I can’t imagine a good business case for now…

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danielravennest t1_j1qusz1 wrote

Quantum computers have the potential to solve certain kinds of problems faster than regular computers. IBM is a computer company, so they are investing in quantum computer research. Sometimes research doesn't pay off, but you never make progress unless you try.

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Extension_Bat_4945 t1_j1rgsml wrote

I get that, but normally companies mostly invest in technology/research that will profit in the future. And I’m sceptical quantum computing can return the investment, as I don’t see a business model yet and the investment has been huge.

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nicuramar t1_j1nuwen wrote

> Simulations and cryptography mainly. It might have potential to reduce time complexity of algorithms from exponential to quasi exponential or even polynomial time (n-bit encryption).

Yeah, so cryptanalysis, not cryptography (encryption, decryption, signing, verifying) so much. Cryptanalysis is however still completely infeasible on today's quantum computers.

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workerMcWorkin t1_j1orozx wrote

Does this mean that quantum computers could handle redundant loads in massive proportions?

I’m thinking replacing servers and such.

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pm_me_wet_kittehs t1_j1qfjt9 wrote

pretty much anything that current tech can do efficiently, is not a problem a quantum computer can, and vice versa.

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Goliath--CZ t1_j1nuj32 wrote

So you're saying that there might one day be a quantum computer that can only run crisis extremely well?

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