Is it possible to compare if two systems in a superposition are equal or not equal to each other, i.e. two systems with two electrons in superposition?

At first:

  1. Superposition of two electrons (state unknown)

  2. Superposition of two electrons (we know that after the measurement the value will be $01$)

We compare the two superpositions:

Comparison of 1 and 2 would return false, so we know that 1. after the measurement is not $01$, but another value, i.e. $10$

Does the no-cloning theorem apply in a manner that I could not create a clone of the first system and then compare it with 1 to get "true"?

Edit: It could very well be that I misunderstood something, I'm only an amateur in physics.

  • $\begingroup$ Do you want to check without disturbing the states? Also, do you know the possible states? $\endgroup$ Mar 29, 2019 at 13:40
  • $\begingroup$ Yes, without disturbing the states & either way for the possible states $\endgroup$ Mar 29, 2019 at 13:50
  • $\begingroup$ Can you clarify what you are asking? Do you mean that system 1, after measurement is in a superposition of states 0 and 1? And what do you mean by 'comparison' would return false? $\endgroup$
    – gabe
    Mar 29, 2019 at 13:51
  • $\begingroup$ Do you know what are the possible superposition states? Or are they arbitrary? $\endgroup$ Mar 29, 2019 at 13:52
  • 1
    $\begingroup$ In quantum theory, we usually say that 2 electrons are identical. Therefore the state is neither 1. or 2. but an anti-symmetric combination $\frac{1}{\sqrt{2}}(|1>|0>-|0>|1>)$. This postulate directly gives the Pauli principle for fermions. en.wikipedia.org/wiki/… $\endgroup$ Mar 29, 2019 at 13:54


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.