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Guffie
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Homework Statement
If you have a three energy level system, with energies 0, A, B where B>A, which consists of only two particles what is the probability that 1 of the particles is in the ground state? What about if two of them are in the ground state? Do this using both fermi and boson statistics.
Homework Equations
Using Fermi-statistics,
Z=exp(-β*A)+exp(-β*B)+exp(-β*(A+B))
Using Boson statistics,
Z=1+exp(-β*A)+exp(-2 β*A)+exp(-β*B)+exp(-2 β*B)+exp(-β*(A+B))
The Attempt at a Solution
For 1 particle in the ground state,
In fermi statistics there are two arrangments which satisfy this condition,
when 1 particle is in the ground state and the other in A, and when the other is in B.
P = Pg(Pa+Pb) = (1/Z)(exp(-β*A)/Z + exp(-β*B)/Z)
Does that look correct?
Would be a similar answer for boson statistics, just with the different partition function.
For both particles in the ground state
Fermi:
P = Pg1 Pg2 = (1/Z)(1/Z) = Z-2
This doesn't look correct, the answer should be zero because fermions can't be in the same energy level..
Can anyone see what I have done wrong?
Boson is the same answer with the different partition function, though its correct that the answer is non-zero here.
Have I done the probabilities incorrectly?