Swap test
swap_test
swap_test(
state1: QArray[QBit],
state2: QArray[QBit],
test: Output[QBit],
) -> None
[Qmod Classiq-library function]
Tests the overlap (in terms of fidelity) of two quantum states.
The fidelity of state1 and state2 is calculated from the probability of measuring test qubit in the state 0 as follows:
\[
|\langle state1 | state2 \rangle |^2 = 2*Prob(test=0)-1
\]
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
state1
|
QArray[QBit]
|
A quantum state to check its overlap with state2. |
required |
state2
|
QArray[QBit]
|
A quantum state to check its overlap with state1. |
required |
test
|
Output[QBit]
|
A qubit for which the probability of measuring 0 is \(0.5*(|\langle state1 | state2 \rangle |^2+1)\) |
required |