
Ask HN: Can quantum computers represent imaginary number i? - alexfromapex
If the imaginary number i is defined as sqrt(-1)<p>and a quantum computer could have a number be simultaneously 1 and -1 due to superposition would that allow the square root to be solved by a quantum representation that is a combination of both?
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kadoban
A regular computer can already represent i. You can do complex math on them
fine, it's just a matter of specifying what the bits mean and the rules they
follow.

I don't think that has anything to do with quantum or not, and I'm not sure
what there is to "solve" about the sqrt(-1). We know what it is, it's just
called i in the complex numbers (by definition). There's not another level to
go down and explore. (in some other number systems, like the reals, sqrt(-1)
just doesn't exist because no number times itself is -1).

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throwawaymath
For example by representing numbers as pairs ( _a_ , _b_ ), where the real
part is _a_ and the imaginary part is _b_. Then:

1 = (1, 0)

 _i_ = (0, 1)

2 + 3i = (2, 3)

and so on.

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fortran77
Fortran 77, my favorite programming language, supported imaginary numbers.
Back in 1977

[https://www.obliquity.com/computer/fortran/datatype.html](https://www.obliquity.com/computer/fortran/datatype.html)

Fortran IV, did, too:

[http://www.math-
cs.gordon.edu/courses/cs323/FORTRAN/fortran....](http://www.math-
cs.gordon.edu/courses/cs323/FORTRAN/fortran.html)

...in 1957.

