Question

assume that we are working in units such that ℏ=1. When providing Bloch sphere coordinates, please ensure that 0≤θ≤π and 0≤ϕ<2π whenever applicable.
we start with the qubit |ψ(0)⟩=|0⟩ and we apply a magnetic field in the x^ direction at t=0. This corresponds to the Hamiltonian H=BX, where B is a constant and X is the usual bit flip gate. What are the coordinates (θ,ϕ) of this qubit on the Bloch sphere at time t, as a function of B and t?

Answer 1

please gelp

Answer 2

Have you gotten anywhere with this one yet?