# How to know positive or negative phrase from qshere diagram?

How to find out whether it is a positive or negative $$\pi$$ phrase between 00 and 11 from q-Sphere diagram?

The phase corresponding to the color of state $$|11\rangle$$ is $$e^{i \pi}= -1$$. So, it is a negative phase.

Generally, you plug in whatever angle the color of the state corresponds to into $$e ^{i \theta}$$ to get the phase of the state.

As per @epelaaez's answer: the node color indicates the relative phase. However, there is a subtle point here.

Ψ = [8 / 17, 0, 0, 15j / 17]
plot_state_qsphere(Ψ, show_state_phases = True)


the result will be

You can see that $$|11⟩$$ is displayed with phase = $$0$$ although it has a phase greater than zero. On the other hand, $$|00⟩$$ is displayed with a phase while it does not have one! This is because plot_state_qsphere function removes the phase from the term with maximum probability, and normalizes the phases of other terms accordingly.