107 votes

Is quantum computing just pie in the sky?

I'll be trying to approach this from a neutral point of view. Your question is sort of "opinion-based", but yet, there are a few important points to be made. Theoretically, there's no ...
Sanchayan Dutta's user avatar
53 votes
Accepted

Is quantum computing just pie in the sky?

Is quantum computing just pie in the sky? So far it is looking this way. We have been reaching for this pie aggressively over the last three decades but with not much success. we do have quantum ...
user1271772 No more free time's user avatar
38 votes

Is quantum computing just pie in the sky?

Classical computing has been around longer than quantum computing. The early days of classical computing is similar to what we are experiencing now with quantum computing. The Z3 (First Turing ...
Victory Omole's user avatar
22 votes

Is quantum computing just pie in the sky?

Early classical computers were built with existing technology. For example, vacuum tubes were invented around four decades before they were used to make Colossus. For quantum computers, we need to ...
James Wootton's user avatar
20 votes

Is quantum computing just pie in the sky?

When you ask whether it is pie in the sky, that rather depends on what promises you think quantum technologies are trying to fulfil. And that depends on who the people are making those promises. ...
Niel de Beaudrap's user avatar
19 votes

Is quantum computing just pie in the sky?

TL,DR: Engineering and physics arguments have already been made. I add a historical perspective: I argue that the field of quantum computation is really only a bit more than two decades old and that ...
Martin's user avatar
  • 349
13 votes
Accepted

How Mature is the Tensorflow Quantum Library

First we should take a step back. Is there any machine learning done a quantum computer that cannot be efficiently simulated on a classical computer? The answer currently (2020) is no. In this ...
dabacon's user avatar
  • 695
13 votes

Are there any uses for Shor's algorithm other than breaking public key cryptography

A bit of an esoteric answer: there is a particular proposal for post-quantum cryptography called "CSI-FiSh", based on isogenies. Without getting too deep into the number theory, the ...
Sam Jaques's user avatar
  • 2,024
12 votes

Is quantum computing just pie in the sky?

TL;DR: I've been working on the theory of quantum computers for about 15 years. I've seen nothing convincing to say that they won't work. Of course, the only real proof that they can work is to make ...
DaftWullie's user avatar
  • 58.1k
12 votes

Is quantum computing just pie in the sky?

To answer part of the question, "will I ever buy a quantum computer", etc. I think there is a fundamental misunderstanding. Quantum computing isn't just classical computing but faster. A quantum ...
Vectorjohn's user avatar
12 votes

Are there any uses for Shor's algorithm other than breaking public key cryptography

community wiki It's an interesting question to pose which problems reduce to factoring (or discrete log), and whether any of those problems could be of practical value. In general I think the ...
10 votes

What could be the possible future applications for HHL algorithm?

A couple years ago it was shown in Quantum algorithms and the finite element method by Montanaro and Pallister that the HHL algorithm could be applied to the Finite Element Method (FEM) which is a "...
SLesslyTall's user avatar
  • 1,626
10 votes

Can quantum computing be profitable without quantum hardware?

You have two different questions here: 1) Can quantum computing be profitable without quantum hardware? In the comments people have said this is an opinion based question, but the truth is that ...
user1271772 No more free time's user avatar
9 votes

Is quantum computing just pie in the sky?

Why would you expect two different technologies to advance at the same rate? Simply put, quantum computers can be immensely more powerful but are immensely harder to build than classical computers. ...
Anti Earth's user avatar
9 votes
Accepted

What kind of real-world problems (excluding cryptography) can be solved efficiently by a quantum algorithm?

I won't be giving any precise statements about which problems can be solved more efficiently using quantum algorithms (compared to existing classical algorithms) but rather some examples: Discrete ...
Sanchayan Dutta's user avatar
9 votes

Is quantum computing just pie in the sky?

The sad truth for most of the people here is that John Duffield (the asker) is right. There is no proof that a quantum computer will ever be of any value. However, for the companies that have ...
user1271772 No more free time's user avatar
9 votes

Is quantum computing just pie in the sky?

See the timeline on Wikipedia, and ask yourself where's the parallel adder? It seems to me that your answer lies in your question. Looking at the timeline on Wikipedia shows very slow progress from ...
CramerTV's user avatar
  • 190
9 votes
Accepted

Number of Qubits Required for Simulation of Caffeine and Penicillin Molecules

I'm not sure if the 286 qubit estimate has ever been fully explained, but we can backwards reason about how to get to the figure. First off, accuracy of quantum chemistry simulations via ...
C. Kang's user avatar
  • 1,716
9 votes
Accepted

Can quantum computing contribute to the development of artificial intelligence?

In my view, if artificial general intelligence (AGI) is ever 'solved', it likely won't be because of the development of a quantum AI algorithm. Rather, it will be because of a breakthrough in the ...
Greenstick's user avatar
  • 1,076
9 votes
Accepted

Does the quantum Fourier transform have many applications beyond period finding?

Given that the QFT is exponentially faster than the FFT, The problem with quantum computing is that they are not actually parallel computers: One is tweaking the qubits in such a way that when ...
emacs drives me nuts's user avatar
8 votes

What is quantum computing vs. what is not quantum computing

The difficulty with explaining quantum computing is that quantum objects and processes have no direct classical analogue; they're an entirely new ontological category. For example, you might have ...
ahelwer's user avatar
  • 4,128
7 votes

What use has quantum computing been?

There are a lot of interesting applications that use similar technology. A lot of labs that work towards quantum computing also publish papers with these applications. Here are some: All-optical ...
Steven Sagona's user avatar
7 votes

Is quantum computing just pie in the sky?

There are many technical challenges to developing a universal quantum computer consisting of with many qubits, as pointed out in the other answers. See also this review article. However, there may be ...
Count Iblis's user avatar
7 votes
Accepted

Anything in between quadratic and exponential speedups?

A subexponential-time quantum algorithm for the dihedral hidden subgroup problem by Kuperberg. Constructing elliptic curve isogenies in quantum subexponential time by Childs, Jao, and Soukharev. A ...
Egretta.Thula's user avatar
6 votes

Claimed "potential revenue" from machine learning in 2023?

"IonQ is claiming to have a potential application in machine learning by 2023. What applications could they have in mind?" None. The plot you showed has no units on the y-axis. It doesn't ...
user1271772 No more free time's user avatar
5 votes

Does quantum computing have an essential advantage in analyzing/controlling chaotic systems?

No. Chaos (as described in chaotic systems) is deterministic, and the evolution of such a system can be calculated using classical deterministic equations. The problem is the strong divergence of the ...
Sir Cornflakes's user avatar
5 votes

What could be the possible future applications for HHL algorithm?

Rebentrost et al. recently used the HHL09 algorithm in their A Quantum Hopfield Neural Network (2018) paper, for optimization of the Hopfield network's energy function. Basically, if the Lagrangian (...
Sanchayan Dutta's user avatar
5 votes
Accepted

What are some current applications of Quantum Computing in drug discovery? Are there any test examples of this?

There are several startups that have formed around QC-assisted drug discovery. The ones listed below have resources on their websites that you might find helpful. ProteinQure Qulab HQS Kuano For a ...
Jonathan Trousdale's user avatar
5 votes
Accepted

What are the practical applications of quantum computing in engineering by the year 2030?

Introduction Similar to this answer, I will say that quantum computers that are capable of doing calculations that are industry-relevant, do not yet exist (and probably won't exist for at least a ...
user1271772 No more free time's user avatar

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