A particle of mass m in the one-dimensional harmonic oscillator is in a state for which a measurement of the energy yields the values ℏω/2 or 3ℏω/2, each with a probability of one-half. The average value of the momentum ⟨px⟩ at time t=0 is mωℏ/2. This information specifies the state of the particle completely. What is this state and what is ⟨px⟩ at time t?