14. Compute (0|p|0) and (0\f*|0).

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PLEASE ANSWER #14.  The first page is provided for context.

7. Find An by normalizing |n). Suggestion: Compute (n|n) for n=0,1,2,3 then find the
pattern. Use the identity (Qflg) = (fIQ*lg) for Q = ât.
8. Show that n) are the eigenvectors of H, i.e.,
ÊĤ \n) = En \n)
(7)
is satisfied. Find the energy eigenvalue En. Knowing that H is an observable, what
can you tell about (m|n) for m + n?
9. Using your results, show that the following formula holds:
ât \n) = Vn+1 |n+ 1)
â \n) = Vn |n – 1)
(8a)
(8b)
Do this either by giving a general proof or by showing that they hold forn=
= 0,1, 2, 3.
10. Let's go back to Eq.(2). What is the SI unit of the coefficient
-? Does it make
2mw
sense to you?
11. Show that the square of position operator is
(âtât + âtâ + âât + ââ)
2mw
(9)
12. Compute (0|î|0) and (0|â²|0). This can be done very efficiently if you use Eq.(8)
13. Find the expression of the momentum operator square, p, in terms of the Fock oper-
ators.
14. Compute (0|p|0) and (0|p²|0).
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Transcribed Image Text:7. Find An by normalizing |n). Suggestion: Compute (n|n) for n=0,1,2,3 then find the pattern. Use the identity (Qflg) = (fIQ*lg) for Q = ât. 8. Show that n) are the eigenvectors of H, i.e., ÊĤ \n) = En \n) (7) is satisfied. Find the energy eigenvalue En. Knowing that H is an observable, what can you tell about (m|n) for m + n? 9. Using your results, show that the following formula holds: ât \n) = Vn+1 |n+ 1) â \n) = Vn |n – 1) (8a) (8b) Do this either by giving a general proof or by showing that they hold forn= = 0,1, 2, 3. 10. Let's go back to Eq.(2). What is the SI unit of the coefficient -? Does it make 2mw sense to you? 11. Show that the square of position operator is (âtât + âtâ + âât + ââ) 2mw (9) 12. Compute (0|î|0) and (0|â²|0). This can be done very efficiently if you use Eq.(8) 13. Find the expression of the momentum operator square, p, in terms of the Fock oper- ators. 14. Compute (0|p|0) and (0|p²|0). CS Scanned with CamScanner
The Fock operator â is defined by
(±+ mu)
å -
â =
(1)
2h
where î and p are the position and momentum operators, respectively.
1. Write down ât in terms of £ and p.
2. Show that
(ât + â)
2mw
(2)
||
himw
p = i
(ât – â)
2
(3)
%3D
hold.
3. Show that the cannonical communation relation, [ê, f] = iħ, yields the so-called bosonic
commutation relation,
(â, ât] = 1.
(4)
4. Show that the Hamiltonian of the SHO, H =
2m
is written as
ÎĤ = f (N +)
(5)
where N = âtâ is called the number operator.
5. Show that Ñ is Hermitian. Suggestion: Use the identity from Exercise #1, (QR)t =
6. A normalized vector |0) (so that (0|0) = 1) is defined to satisfy â|0) = 0. With this
the following vectors are constructed:
|n) = An (ât)" |0) for n =
0,1,2,...
(6)
where A, are constant with Ao = 1. Compute N|n) for n =
are the eigenvectors of N, i.e., Ñ|N) is proportional to |N). Find the eigenvalues of
N from the proportionality.
0,1,2,3 to show that these
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Transcribed Image Text:The Fock operator â is defined by (±+ mu) å - â = (1) 2h where î and p are the position and momentum operators, respectively. 1. Write down ât in terms of £ and p. 2. Show that (ât + â) 2mw (2) || himw p = i (ât – â) 2 (3) %3D hold. 3. Show that the cannonical communation relation, [ê, f] = iħ, yields the so-called bosonic commutation relation, (â, ât] = 1. (4) 4. Show that the Hamiltonian of the SHO, H = 2m is written as ÎĤ = f (N +) (5) where N = âtâ is called the number operator. 5. Show that Ñ is Hermitian. Suggestion: Use the identity from Exercise #1, (QR)t = 6. A normalized vector |0) (so that (0|0) = 1) is defined to satisfy â|0) = 0. With this the following vectors are constructed: |n) = An (ât)" |0) for n = 0,1,2,... (6) where A, are constant with Ao = 1. Compute N|n) for n = are the eigenvectors of N, i.e., Ñ|N) is proportional to |N). Find the eigenvalues of N from the proportionality. 0,1,2,3 to show that these CS Scanned with CamScanner
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