As previously mentioned, the expectation value of each Pauli matrix is a component of the Bloch vector, ⟨ σ i ⟩ = ψ † σ i ψ = R i {\displaystyle \langle \sigma _{i}\rangle =\psi ^{\dagger }\sigma _{i}\psi =R_{i}} . Equating the left and right hand sides, and noting that 2 μ ℏ {\displaystyle {\frac {2\mu }{\hbar }}} is the gyromagnetic ratio γ {\displaystyle \gamma } , yields another form for the equations of motion of the Bloch vector