Codercise H.4.1a Potential Mistake

Codebook
1

Hi. Under the Energy levels and time evolution section in the theory section, equation (1) seems to only hold true for odd powers of (Z@Z) (i.e. (Z@Z)^2m+1). That is, when it is to an even power, (Z@Z)^2m = (I@I), so (Z@Z)^2m |xy> = (I@I)|xy> = |xy>.

2

Hi @cyyoung
Thanks for your question.
I’ll check the math and get back to you next week.

1 Like
3

Hi!
I checked your statement and it is true. However, why is this a potential mistake in the Codebook? The section is making an assumption at the beginning about the form of the Hamiltonian H=\alpha Z \otimes Z and at any stage it claims to be general.
Let me know! Thanks!

4

Oh. Thank for your reply. I thought the codebook was taking
image
for granted and just putting it into the exponent.
Because of this
image
I assumed that the Hamiltonian (Z@Z) is just following this.

Thanks alot!