I Bob and Alice with a Bell pair

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Bob and Alice share a Bell pair, and the discussion focuses on how Alice can compute the density matrix for her particle. A participant recalls using a 4x4 matrix and summing values to derive Alice's density matrix. There is an emphasis on the importance of conducting prior research on density matrices and entanglement before asking for help. The conversation highlights the need for personal effort in understanding the topic, especially given the complexities involved. Overall, the thread underscores the significance of foundational knowledge in quantum mechanics for accurate calculations.
Heidi
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Hi Pfs
If Bob and Alice share a bell pair 0>0> + 1>1>
I cannot remember , how Alice compute the density matrix of hes own particle.
thanks.
 
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Heidi said:
Hi Pfs
If Bob and Alice share a bell pair 0>0> + 1>1>
I cannot remember , how Alice compute the density matrix of hes own particle.
thanks.
This is PF, we ask you to first look it up and show us what you have done so far before commenting on it.
 
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I remember that we wrote a 4 by matrix in a set of 4 by 4 matrix
and summing for ech ons 2 values and getting what Alice density matrix has.
I had a stroke in my brain 2 months ago and i still have problems.
µ
 
Heidi said:
I remember that we wrote a 4 by matrix in a set of 4 by 4 matrix
and summing for ech ons 2 values and getting what Alice density matrix has.
I had a stroke in my brain 2 months ago and i still have problems.
µ
Again it is not about what you remember but what effort have you done so far. Have you look up for "density matrix and entanglement"?
 
For the quantum state ##|l,m\rangle= |2,0\rangle## the z-component of angular momentum is zero and ##|L^2|=6 \hbar^2##. According to uncertainty it is impossible to determine the values of ##L_x, L_y, L_z## simultaneously. However, we know that ##L_x## and ## L_y##, like ##L_z##, get the values ##(-2,-1,0,1,2) \hbar##. In other words, for the state ##|2,0\rangle## we have ##\vec{L}=(L_x, L_y,0)## with ##L_x## and ## L_y## one of the values ##(-2,-1,0,1,2) \hbar##. But none of these...

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