Explore BrainMass
Share

# Time evolution of a superposition of two energy eigenstates

This content was STOLEN from BrainMass.com - View the original, and get the already-completed solution here!

See the attached file.

https://brainmass.com/physics/schrodinger/time-evolution-superposition-energy-eigenstates-181429

#### Solution Preview

The Schrödinger equation is:

i hbar d|psi>/dt = H|psi> (1)

The initial state is:

|psi(t=0)> = N(|1> + |2>)

where |1> and |2> are two eigenstates of the Hamiltonian:

H|1> = E1 |1>

H|2> = E2 |2>

And E1 is not equal to E2 (by definition as the two states are nondegenerate)

The normalization constant N = 1/sqrt(2) is |1> and |2> are normalized.

We can solve Eq. (1) as follows. Since the equation is a linear differential equation, a superposition of two solutions is another solution. Such a superposition will satisfy the superposition of the initial conditions of the individual solutions. Now, we can write any state as a superposition of eigenstates of the Hamiltonian. So, all we need to do is to solve Eq. (1) for the initial condition were ...

#### Solution Summary

A detailed solution is given regarding time evolution of a superposition of two energy eigenstates.

\$2.19

## States of a Quantum Harmonic Oscillator

6. Consider the state of a harmonic oscillator initially (t=0) to be given by |phi >= 5|0 + 12| 1>.
(a) Find the normalized state.
(b) What will be the state of the particle after time t.
(c) Calculate < x > and < p > for this state at time t. Is this classically what you would expect?

View Full Posting Details