## Re-working Mathematica file

Hi there

I was sent a .nb file with calculations already done for me, for various inputs.

I was wondering how I can edit those inputs, keeping the rest of the calculations the same, to find out what the result would be?

(see attached file for example)
Attached Thumbnails

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 /. is Mathematica for "substitute in the previous expression using the following rules." var->expression is Mathematica for a rule. If you insert somevar=someconstant before any of your lines giving your substitutions it is possible and perhaps even likely that it will break the code for one or more complicated reasons. If you could be more specific about what you want to edit and what you want to keep the same then it should be possible for someone to give you an idea how to proceed.
 All the lines with //Simplify // Expand are the rules I wish to keep. Its just the input s0 I wish to change, which will change what's under s2 and before s3... if that makes any sense?

## Re-working Mathematica file

 Quote by StevieTNZ Its just the input s0 I wish to change
Then try changing the
s0:=stuff
to
s0:=newstuff

and then evaluate the notebook. Then CAREFULLY CHECK to see if you get the correct result.

As I warned previously, this may break the code, but with none of the people who have seen your various posts having any idea about what you are going to change s0 to then none of us will likely be able to tell you whether it will work or not. So hope for the best and figure out how to fix it if this breaks it. I hope it works.

 Well that didn't turn out to be that hard..... managed to get the calculation. (Figured out that bH should be changed to -bH to convert H into - H)
 It seems that displaying an output based on my input, running the calculation backwards, i.e. output -> input, turns up a different result. Would that be an indication that my input (into what was there previously) has changed something? [Equation 1: There is an input where it calculates an output. Equation 2: Based on that output, I can insert that somewhere else where it will run the calculation backward and turn up the input I placed in Equation 1.]

See attached the .nb file, unedited with my own inputs (i.e. the file sent to me with already defined inputs).

Changing the first input from bH*cV to bV*-cH produces an output. Copying that output into the next calculation, where the input is defined as bHpp*cVpp, produces an output different to the input bV*-cH which was used for the top calculation.
Attached Files
 State transformations.nb (18.7 KB, 5 views)

 It is difficult for me to understand exactly what you think the problem is. One guess is that in your "forward" calculation you turn bH into bHp+I*cHp. In your "reverse calculation you seem to attempt to reverse that by subtracting I*cHp. That certainly seems like it would reverse the process. But in both cases you also divide by Sqrt[2]. That seems to break your attempt at reversing the process. My guess is you need to multiply by Sqrt[2] to reverse the previous division by Sqrt[2]. This guess seem compatible with you appearing to end up with an extra division by 2 at the end of your attempt to reverse the process. But you also end up with extra minus signs and powers of bH and cV. I am guessing, but nothing more than that, that there are other little errors in your long chain of substitutions that attempt to reverse the process. Does any of this make sense?

I've been told perhaps it is best to use Ket notions to solve the issue at hand.

I was helped with the input, as well as where to place the complex number i in the s1 = ... equation. (I wonder if what I have written is correct, in terms of Ket notions written in Mathematica?)

But I'm not entirely sure how to pass the result of s1 into s3, for conversion into R/L polarisations, especially if I am required to place the i outside the Ket function. Also, if I define Ket[hp, b] ->, would that also take those Ket's with [hp, b], as well as i, before them?
Attached Files
 Mathematica-2.nb (50.1 KB, 1 views)