Differentiating Qubits

1. Jul 15, 2008

Dragonfall

Given two arbitrary qubits, is there a test I can do that will always tell orthogonal qubits apart (but may fail if they are not)? Does it necessarily destroy the qubits' states?

2. Jul 16, 2008

neu

I'm a bit rusty with Quantum info.

Qubits are only distinguishable from eachother if they are mutually orthogonal. This is because you can only make simutaneous measurement in an orthogonal basis (I think).

3. Jul 16, 2008

peter0302

I'm a little rusty as well - but isn't it just like any other HUP-susceptible quantum object - if you can differentiate the states, you've destroyed the states?

4. Jul 16, 2008

Dragonfall

Is it possible to turn a qubit into an orthogonal one without measuring first? Turn it 90 degrees, so to speak.