13 votes

Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used?

Here is a quick list of notable differences between analog and quantum computers: Analog computers can't pass Bell tests. The state space of an analog computer with N sliders is N dimensional. The ...
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  • 22.4k
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 ...
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8 votes

Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used?

What work has been done on the mapping of quantum phenomena to analog computing, and learning from that analogy? A starting place (with a lot of good references) to learn about analog quantum ...
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7 votes

Is there any single-logical-qubit physical device out there as of end 2018?

A logical qubit is a very fluid concept. You could use physical qubits as logical qubits. Or, you can encode multiple physical qubits as a single logical qubit. The more physical qubits you use, the ...
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  • 47.1k
6 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 ...
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6 votes
Accepted

What is the status of quantum computing compared with other (photonic) quantum technologies?

According to this UK-oriented report by Gooch and Housego dated May 8, 2018, quantum computing is only one of several main key applications expected to have a market impact: Clock technology/...
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  • 3,637
5 votes
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Do the 'fundamental circuit elements' have a correspondence in quantum technologies?

When you ask, I am wondering whether these elements would be somehow imitated by the means of quantum technologies there are different levels on which you can interpret this question. You might ...
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4 votes

Can quantum computing be profitable without quantum hardware?

In complement to the other answer from @user1271772: 1) Can quantum computing be profitable without quantum hardware? I can add another two elements. First companies that can sell/develop anti-...
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  • 4,564
4 votes

What use has quantum computing been?

Perform and checking basic quantum-mechanic experiments Before the IBM and alibaba quantum cloud computers, you would need an expensive lab to do simple CHSH or GHZ experiments. Of course the qubits ...
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  • 499
4 votes
Accepted

Are there any other companies besides Microsoft pursuing topological QC?

Microsoft is the only company that is trying to build a topological quantum computer. You mention that topological qubits handle noise far better than other systems, but they are also theoretical. ...
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4 votes
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Breakthroughs in quantum computing using non-standard quanta

The only two quasi-particle quanta for which I know there to be active research in quantum computing are phonons and anyons. Phonons: That state-of-the-art is given my answer here: Phononic Quantum ...
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4 votes

Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used?

Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used? No, they are not. The digital vs analog factor is not the point here, the ...
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  • 18.7k
3 votes

Are quantum computers just a variant on Analog computers of the 50's & 60's that many have never seen nor used?

Have we fallen into the same 'everything digital' bandwagon trap that keeps recurring? What I have noticed is more the 'everything binary' bandwagon trap; which reminds me of the Grandma's cooking ...
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  • 3,202
3 votes

What use has quantum computing been?

Thinking about the theoretical capabilities of quantum computers has led to important insights on the theory of classical computers. One example is the proof that the (classical) complexity class PP ...
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  • 2,107
3 votes
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Period of phase leads the advantage of Heisenberg's Limit disappear?

You are correct, but the SQL is a local limit, when you already have a very good idea what the value of $\theta$ is, so there is no contradiction. Let's work through it. You measure some relative ...
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3 votes

What constitutes a quantum database?

It is a very interesting question. Quantum database would be a correlated collection of entangled ensembles of quantum data structures such as bloom filters, quantum graphs and quantum time series ...
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2 votes

Can quantum computing be profitable without quantum hardware?

At this early stage of quantum technology development, a useful starting point to understand the "expectation of profitability" is to look at the private markets (angel investing, venture capital, ...
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2 votes

What use has quantum computing been?

Executing a NISQ-device in a manner that asymptotically outperforms a classical computer invalidates the Extended Church-Turing Thesis (ECT). Voluminous tomes written about the (non-extended) Church-...
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  • 7,017
2 votes

Do the 'fundamental circuit elements' have a correspondence in quantum technologies?

I am wondering whether these elements would be somehow imitated by the means of quantum technologies and what would be the requirements to achieve them I don't think we would want to achieve quantum ...
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  • 388
1 vote

Breakthroughs in quantum computing using non-standard quanta

I'm not sure if you count adiabatic quantum computing as fringe, but there was a paper using 4 NMR qubits to implement a adiabatic analogue to HHL which allowed them to invert an 8x8 operator with 98....
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