Go to the U of M home page
School of Physics & Astronomy
School of Physics and Astronomy Wiki

User Tools

Trace:
classes:2009:fall:phys4101.001:q_a_1204

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
classes:2009:fall:phys4101.001:q_a_1204 [2009/12/07 02:05] – x500_santi026classes:2009:fall:phys4101.001:q_a_1204 [2009/12/13 21:09] (current) – youmans
Line 34: Line 34:
 I've got a question I've been meaning to ask for a while but keep forgetting to post...A while back I was reading through the Angular Momentum chapter again, and came across the part where they're talking about how the Lx, Ly, and Lz commutators go.  In equation 4.97, they jump to equation 4.98 while dropping two terms and simplifying the remaining....Now it looks like all they did was pull a y px out of the first term, and an x py out of the second term, even though each is only associated with one of the two terms.  Is there some identity that lets you do this, or does it just work out this way by expanding the commutators and doing algebra? I've got a question I've been meaning to ask for a while but keep forgetting to post...A while back I was reading through the Angular Momentum chapter again, and came across the part where they're talking about how the Lx, Ly, and Lz commutators go.  In equation 4.97, they jump to equation 4.98 while dropping two terms and simplifying the remaining....Now it looks like all they did was pull a y px out of the first term, and an x py out of the second term, even though each is only associated with one of the two terms.  Is there some identity that lets you do this, or does it just work out this way by expanding the commutators and doing algebra?
  
 +=== Jake22 12/13 1707 ===
 +This is simply a matter of expanding it and noting that y commutes with px, and x with py, as in equation 4.10.
  
 ==== Esquire 12/4 1611 (Age of Military Time)==== ==== Esquire 12/4 1611 (Age of Military Time)====
Line 59: Line 61:
 == ice IX 12/7 01:50 == == ice IX 12/7 01:50 ==
 I thought the <math>\frac{1}{sqrt{2}}</math> came from normalization of the "spinor" state.  I thought the <math>\frac{1}{sqrt{2}}</math> came from normalization of the "spinor" state. 
 +
 +==Pluto 4ever 12/10 7:21PM==
 +It mainly comes from Eq. 4.177 in part that we are dealing with antisymmetric state for this situation.
 +
 +===Blackbox 12/10===
 +For example, let's look at the first term, (Sx(1)*Up-spin)=(h_bar/2*Down-spin).
 +As you remember this, Sx can be written by (S+ + S-)/2. If you substitue this for Sx(1), then you would get the first term and the rest of terms can be solved in similar way. I hope this helped.
 +
 +
 --------------------------------------- ---------------------------------------
 **Return to Q&A main page: [[Q_A]]**\\ **Return to Q&A main page: [[Q_A]]**\\
 **Q&A for the previous lecture: [[Q_A_1202]]**\\ **Q&A for the previous lecture: [[Q_A_1202]]**\\
 **Q&A for the next lecture: [[Q_A_1207]]** **Q&A for the next lecture: [[Q_A_1207]]**
classes/2009/fall/phys4101.001/q_a_1204.1260173123.txt.gz · Last modified: 2009/12/07 02:05 by x500_santi026

Page Tools