Monday

August 31, 2015
Posted by **qwerty** on Saturday, April 6, 2013 at 2:56am.

-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**, Saturday, April 6, 2013 at 1:15pm|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**, Saturday, April 6, 2013 at 3:03pmAnd, 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**, Sunday, April 7, 2013 at 3:33pmAnswers to q6 and 8 ?

- Quantum Physics -
**hikikomori**, Sunday, April 7, 2013 at 10:18pmPlease q6 and q8 !

- Quantum Physics -
**help**, Monday, April 8, 2013 at 2:17pmprob 3 C

- Quantum Physics -
**Im Anononous**, Tuesday, April 9, 2013 at 8:35am3C 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

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**s**, Tuesday, April 9, 2013 at 8:44amThank you.

And waiting for the rest answers

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**Help plz**, Tuesday, April 9, 2013 at 10:44am5 plz....

- Quantum Physics -
**Help plz**, Tuesday, April 9, 2013 at 10:51am7a 1/2 7b 1/2

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**Anonymous**, Wednesday, April 10, 2013 at 2:40amProblem 9 plzz

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**BOB**, Wednesday, April 10, 2013 at 2:54am8D ,8E,6C,6D and 9

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**Anne**, Thursday, April 11, 2013 at 5:07am9 is 175.8

Anyone 8D ,8E,6C,6D?

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**Mary**, Thursday, April 11, 2013 at 11:43am6C,6D,8C,8D please..

- Quantum Physics -
**Bel**, Thursday, April 11, 2013 at 4:03pm4a,b,c,d plz ?

- Quantum Physics -
**helper**, Thursday, April 11, 2013 at 5:14pmfor 4 some one already gave you so you have:

4a: 1/sqrt(5)

4b 2/5

4c 1/2

4d 0

- Quantum Physics -
**Bel**, Thursday, April 11, 2013 at 7:08pm3a and b please

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**Bel**, Thursday, April 11, 2013 at 7:09pmthx very much helper

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**Gyano**, Thursday, April 11, 2013 at 7:37pm5 plz?

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**Mary**, Friday, April 12, 2013 at 2:28am5A 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**, Friday, April 12, 2013 at 7:12am8c = 1, 1, 0, 0

8D= 1/n,1/n,0,0,1/n,1/n,

Please 6C and 6D

- Quantum Physics -
**Im Anononous**, Friday, April 12, 2013 at 8:35amJLG - 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**, Friday, April 12, 2013 at 8:43am6C and 6D

- Quantum Physics -
**JLG**, Friday, April 12, 2013 at 4:05pm6c: 1/2+1/(2*sqrt(2)

1/2-1/(2*sqrt(2)

6D I continius lost..

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**JLG**, Friday, April 12, 2013 at 4:07pm6D is the same that 6 C :)

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**Gyano**, Friday, April 12, 2013 at 5:07pmthx all, 8e please

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**See you in the Final ;)**, Friday, April 12, 2013 at 6:45pm8e: 0,1/n, 1/n

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**Im Anononous**, Friday, April 12, 2013 at 7:10pmThanks JLG

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**Gyano**, Saturday, April 13, 2013 at 4:51pmTHANKS

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**abdrrahim**, Sunday, April 14, 2013 at 4:08pmTHANKS ANNE

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**Anonymous**, Sunday, April 14, 2013 at 4:34pm6c second part ans. is not accepted,,,wat is its numerical value.

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**See you in the Final ;)**, Monday, April 15, 2013 at 9:16pmHey Guys... Ready for the final??

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**Final ;)**, Tuesday, April 16, 2013 at 11:47amHelloo Any answer for the Final?

- Quantum Physics -
**SS01**, Sunday, September 8, 2013 at 5:46am1] Given qubit 1 in the state 35|0>+45|1> 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) 45|01>−35|11>]

c) 1/√3|01> +1/√3|10>−1/3|11>

d) 1+i/√22|++> − 1+i/√22|+−>

+ 1−i/√22|−+> − 1−i/√22|−−>