r***o
发帖数: 6 | 1 Two spin- particles, 1 and 2, have spins in a singlet state with spin wave f
unction
Q(1,2)=1/20.5[a(1)b(2)- a(2)b(1)]
where a and b refer to up and down spins, respectively, along any chosen axi
s. The spin of particle 1 is measured along the z-axis and found to be up.
8. A simultaneous measurement of the spin of particle 2 along the z-axis wou
ld yield which of the following results?
(A) Up with 100% probability
(B) Down with 100% probability
(C) Up with 25% probability, | k******j
发帖数: 4 | 2
（
自
at first I hot the same answer as you, but if you read the question again, you
will realize the mistake: a and b are states, 1 and 2 are particles. Measure
particle 2, it still has a and b two possible states. so 50% to 50%. 1 and 2
has no relation. Q is a mixed state, not a superposition state.
It's same as above.
【在 r***o 的大作中提到】
: Two spin- particles, 1 and 2, have spins in a singlet state with spin wave f
: unction
: Q(1,2)=1/20.5[a(1)b(2)- a(2)b(1)]
: where a and b refer to up and down spins, respectively, along any chosen axi
: s. The spin of particle 1 is measured along the z-axis and found to be up.
: 8. A simultaneous measurement of the spin of particle 2 along the z-axis wou
: ld yield which of the following results?
: (A) Up with 100% probability
: (B) Down with 100% probability
: (C) Up with 25% probability,
| S*********g
发帖数: 5298 | 3 Since the measurement is simultaneously.
The mesurement of particle 1 should have no effect on the state yet.
If you first measure partilce one, get spin up.
Then, you measure particle 2, you should get spin down for 100%.
【在 r***o 的大作中提到】
: Two spin- particles, 1 and 2, have spins in a singlet state with spin wave f
: unction
: Q(1,2)=1/20.5[a(1)b(2)- a(2)b(1)]
: where a and b refer to up and down spins, respectively, along any chosen axi
: s. The spin of particle 1 is measured along the z-axis and found to be up.
: 8. A simultaneous measurement of the spin of particle 2 along the z-axis wou
: ld yield which of the following results?
: (A) Up with 100% probability
: (B) Down with 100% probability
: (C) Up with 25% probability,
|
|
