# Questions tagged [classical-computing]

For questions about the relation between quantum computing and classical computing, such as their relative performance.

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### References on quantum arithmetic circuit complexity

In classical computing, arithmetic circuit complexity is apparently a big topic. But I couldn't find much about the complexity of quantum arithmetic circuits. Almost all references like arXiv:1805....
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### Implementing piecewise functions on a quantum computer

I am curious about how to do implement functions like $$f(x)=\begin{cases} 2x &\text{if} &0\leq x <0.5 \\ x/2 &\text{if} &0.5\leq x<1 \end{cases}$$ Do we implement this like ...
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### Large size of matrices for little outcome [closed]

I am stuck in a dilemma about how to proceed with a quantum computing algorithm that changes the original state of a system to another. Say I have a superposition of all $8$ bit integer values that ...
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### Is it possible to construct an equivalent quantum circuit from a CORDIC-based digital circuit?

DaftWullie mentions an interesting point here: let's assume that we know an efficient classical computation of $f(x)$. That means we can build a reversible quantum computation that runs in the same ...
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### What is the difference in computational power between qubit and bit (transistor)? [duplicate]

If I use for example 5-qubit IBM-Q quantum computer and we accept the law of quantum parallelism ($n$ qubit = $2^n$ ordinary bits), so does it mean that computational power of this computer is equal ...
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### Is there proof that the D-wave (one) is a quantum computer and is effective?

I'm admittedly a novice in this field, but I have read that, while the D-wave (one) is an interesting device, there is some skepticism regarding it being 1) useful and 2) actually a 'quantum computer'....