Posted by qwerty on .
Consider a particle whose wavefunction at some fixed time t is represented by
A if 2≤x≤0
ψ(x)= A if 0≤x≤3
0 otherwise
(a) What is the normalization constant A?
(b) What is the probability of finding the particle at a position x≤0?
(c) What is the expected value of position x?
(d) What is the expected value of momentum p?

Quantum Physics 
Count Iblis,
psi(x)^2 integrated from minus to plus infinity is 5 A^2, this has to be equal to 1, therefore you can choose A as 1/sqrt(5) (you are free to multiply this by any phase factor
exp(i theta)).
The probability of the aprticle being at negative x is the integral from minus infinity to zero of psi(x)^2 dx, which is 2/5.
Expacted position: Integrate
x psi(x)^2 dx from minus to plus infinity, you get <x> = 1/2. 
Quantum Physics 
Count Iblis,
And, of course <p> = 0, because the fact that psi(x) is (or can be chosen to be a) real function of x, implies that the modulus squared of the momentum space wavefunction
psi(p) is an even function of p. To see this, note that:
psi(x) = 1/sqrt(2 pi hbar) Integral from minus to plus infinity of
dp psi(p) exp(i p x/hbar)
Take the complex conjugate of this:
psi*(x) = 1/sqrt(2 pi hbar) Integral from minus to plus infinity of
dp psi*(p) exp(i p x/hbar) =
1/sqrt(2 pi hbar) Integral from minus to plus infinity of
dp psi*(p) exp(i p x/hbar)
Since psi*(x) = psi(x), this means that
psi*(p) = psi(p)
therefore
psi(p)^2 = psi*(p)psi(p) =
psi(p)psi*(p) = psi(p)^2 
Quantum Physics 
Gyanno,
Answers to q6 and 8 ?

Quantum Physics 
hikikomori,
Please q6 and q8 !

Quantum Physics 
help,
prob 3 C

Quantum Physics 
Im Anononous,
3C is 3/2
6A is pi/2 and pi/4
6B is 1/2 and 1/2
Looking for 6C and 6D
8A is 1/2, 1/2, 0, 0
8B is 0, 0, 1/2, 1/2
8C is 1, 1, 0, 0
Looking for 8D and 8E
8F is No 
Quantum Physics 
s,
Thank you.
And waiting for the rest answers 
Quantum Physics 
Help plz,
5 plz....

Quantum Physics 
Help plz,
7a 1/2 7b 1/2

Quantum Physics 
Anonymous,
Problem 9 plzz

Quantum Physics 
BOB,
8D ,8E,6C,6D and 9

Quantum Physics 
Anne,
9 is 175.8
Anyone 8D ,8E,6C,6D? 
Quantum Physics 
Mary,
6C,6D,8C,8D please..

Quantum Physics 
Bel,
4a,b,c,d plz ?

Quantum Physics 
helper,
for 4 some one already gave you so you have:
4a: 1/sqrt(5)
4b 2/5
4c 1/2
4d 0 
Quantum Physics 
Bel,
3a and b please

Quantum Physics 
Bel,
thx very much helper

Quantum Physics 
Gyano,
5 plz?

Quantum Physics 
Mary,
5A i 0 0 i 5b i 0 0 i 5C 1 1 1
3a is 2nd option 3b is 2nd option
6C,6D,8C,8D please 
Quantum Physics 
JLG,
8c = 1, 1, 0, 0
8D= 1/n,1/n,0,0,1/n,1/n,
Please 6C and 6D 
Quantum Physics 
Im Anononous,
JLG  Thanks for 8D and 8E. Didn't realize n was acceptable.
Anyone have 6C and 6D?
5 a) {{i,0}{0,i}}
5 b) {{i,0}{0,i}}
5 c) 1, 1, 1 
Quantum Physics 
Help,
6C and 6D

Quantum Physics 
JLG,
6c: 1/2+1/(2*sqrt(2)
1/21/(2*sqrt(2)
6D I continius lost.. 
Quantum Physics 
JLG,
6D is the same that 6 C :)

Quantum Physics 
Gyano,
thx all, 8e please

Quantum Physics 
See you in the Final ;),
8e: 0,1/n, 1/n

Quantum Physics 
Im Anononous,
Thanks JLG

Quantum Physics 
Gyano,
THANKS

Quantum Physics 
abdrrahim,
THANKS ANNE

Quantum Physics 
Anonymous,
6c second part ans. is not accepted,,,wat is its numerical value.

Quantum Physics 
See you in the Final ;),
Hey Guys... Ready for the final??

Quantum Physics 
Final ;),
Helloo Any answer for the Final?

Quantum Physics 
SS01,
1] Given qubit 1 in the state 350>+451> and qubit 2 in the state 12√0>+i2√1>, what is the state of the composite system?
in form of a│00> + b│01> + c│10> + d│11>
find a b c d.
2] Which of the following states is entangled?
a) ++>
b) 4501>−3511>]
c) 1/√301> +1/√310>−1/311>
d) 1+i/√22++> − 1+i/√22+−>
+ 1−i/√22−+> − 1−i/√22−−>