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faradayslaw
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Homework Statement
A particle is in the ground state of a half harmonic oscillator (V=m/2 w^2 x^2 x>0, and infinity x<0). At t=0, the barrier at x=0 is suddenly removed. Find the possible energy measurements as a function of time and the wavefunction for all times.
Homework Equations
<H> = <psi|H|psi>, |psi(t)>=Ʃexp(-i*H*t/hbar)|psin(t)> cn
The Attempt at a Solution
At t=0, the wavefunction is in the 1st excited state of the full harmonic oscillator, and due to normalization in the half harmonic oscillator, the ground state of the half HO is √2 times the first excited state for the full one. Thus, |psi(0)> = 1/2^0.5 * |psi1>, and so cn=0 for n≠1 and cn=1/√2 for n=1. We then have |psi(t)> = 1/2^0.5 * |psi1> * exp(-i*(3/2 hb w)t/hb). So, |psi(t)> = 1/2^0.5 * |psi1> * exp(-i*(3/2 w)t). This doesn't seem right to me, since the particle is in such a trivial linear combination of states, but I don't see where I have gone wrong, and it makes sense that the expected energy is unchanged. So, can someone point out if there is a mistake? The possible energies to be measured are only 3/2 hbar w, since the particle is in a trivial superposition of just |psi1>
Thanks