Since the state space of such a particle is the tensor product of the state spaces associated with the individual one-dimensional wave functions, the time-independent Schrödinger equation for such a system is given by- − − ℏ ℏ 2 2 m ( ∂ ∂ 2 ψ ψ ∂ ∂ x 2 + ∂ ∂ 2 ψ ψ ∂ ∂ y 2 + ∂ ∂ 2 ψ ψ ∂ ∂ z 2 ) + 1 2 m ω ω 2 ( x 2 + y 2 + z 2 ) ψ ψ = E ψ ψ