phy-4600/solutions/exam1/prob2

48 lines
725 B
Plaintext
Raw Normal View History

2016-02-21 06:05:07 +00:00
͟d͟ ͟\<͟p͟\>͟ = - 〈͟d͟ ͟V͟(͟X͟)͟〉
dt dx
If a particle is subject to potential 〈V(x)〉
The potential is known, and in the absense of any non-conservative influences, the Hamiltonian is equal to the potential.
H(x) = V(x)
H|E〉 = E|E〉
Ĥ = ͟p̂͟²͟ + V(x̂)
2m
x̂ ≐ x
p̂ ≐ -ι ħ ͟d͟
dx
p̂² ≐ -ħ² ͟d͟²
dx²
Ĥ = ͟p̂͟²͟ + V(x̂)
2m
〈p̂〉 = ∫ dx p(x) =
-∞
d/dt ∫ dx p(x) =
Probably start here:
〈V(x)〉 = ∫ dx V(x)
〈d/dx V(x)〉 = ∫ d/dx V(x) dx = V(x)
d/dt 〈p〉 = d/dt ∫ dx p(x)
the definition of momentum in function space is
d/dt p(x) = -d/dx V(x)