Is there a method how to prepare quantum pure state $|+⟩ = \frac{1}{\sqrt{2}}(|0⟩+|1⟩)$ ? Thanks a lot for concrete answer.

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    $\begingroup$ Sure there is, but the specifics depend on what quantum system do you use to encode the qubit. Is it the polarization of a photon? Is it a spin of electron? Is it something else? You need to be concrete yourself, if you want a concrete answer. $\endgroup$ Mar 23, 2020 at 22:48
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    $\begingroup$ Experimentally? What is the basis for the 0 and 1 states? $\endgroup$
    – SuperCiocia
    Mar 23, 2020 at 23:05
  • $\begingroup$ ... and it actually depends on the basis as well... $\endgroup$ Mar 24, 2020 at 0:40
  • $\begingroup$ On quantum computers based on gate model (e.g. IBM Q), it can be prepared by application of Hadamard gate on state $|0\rangle$. $\endgroup$ Mar 25, 2020 at 15:21

1 Answer 1


Assuming spin basis, prepare an electron with spin up in the z direction using Stern-Gerlach setup. It should be in the desired state along x or y.


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