Clarify confusion between kraus operators and collapse operators

[a-corni]

Given that qutip.mesolve uses collapse operators and not kraus operators, I propose to delete the trace of kraus operators in our code and documentation.

• Modify the name of the variable kraus_ops to local_collapse_ops in set_config.
• Delete the L_0 operators from both notebook and code. Delete condition that first effective operator should be an identity and that sum of probability*operators is equal to identity (that's a condition on kraus operators, not on lindblad operators).
• Replace the link to Preskill's notes to Nielsen and Chuang's "Quantum Computation and Quantum Information" to justify $L_i = p/4 \sigma_i$ in depolarizing noise.
• Replace probabilities by rates in notebook and replace p(1-p)^(n-1) by gamma. Hopefully, the results (in the notebook at least) are not changed significantly.
• [x] Rename variables refering to probabilities to rates. Could we keep probabilities and define the rate as gamma = proba / (duration of the sequence) @dehond ?

Closes #608

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[dehond]

* [ ]  Rename variables refering to probabilities to rates. Could we keep probabilities and define the rate as gamma = proba / (duration of the sequence) @dehond ?

I'd suggest that ideally everything is relabeled as a rate so that nothing depends on the sequence length. If the decay rate of some excited state is 0.1/μs, the probability of decay during 1 μs is (approximately) 0.1, but how do we define the probability of decay during a 10 μs sequence, or longer?

If you'd like to turn it around we face similar issues: we know that the probability of decay during a 10 μs sequence is $1-e^{-1} = 0.63$, but it's not accurate to say that this means that the probability of decay during a 1 μs sequence is $0.63/10 = 0.063$.

[a-corni]

* [ ]  Rename variables refering to probabilities to rates. Could we keep probabilities and define the rate as gamma = proba / (duration of the sequence) @dehond ?

I'd suggest that ideally everything is relabeled as a rate so that nothing depends on the sequence length. If the decay rate of some excited state is 0.1/μs, the probability of decay during 1 μs is (approximately) 0.1, but how do we define the probability of decay during a 10 μs sequence, or longer?

If you'd like to turn it around we face similar issues: we know that the probability of decay during a 10 μs sequence is 1−e−1=0.63, but it's not accurate to say that this means that the probability of decay during a 1 μs sequence is 0.63/10=0.063.

Thanks Julius, I was also puzzled by these issues. I will implement the replacement of variables with _proba into _rate. I will put a DeprecationWarning signaling their deprecation.

[a-corni]

I think the notebook needs to be executed again

It should be good now :)

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HGSilveri commented on 2023-12-14T10:57:44Z ----------------------------------------------------------------

The list does not seem to be rendering correctly on RTD

review-notebook-app[bot] commented 6 months ago

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HGSilveri commented on 2023-12-14T10:57:45Z ----------------------------------------------------------------

I can see you cleared the outputs. Isn't this notebook taking a bit too long to run for it to be rerun on every docs build?

a-corni commented on 2023-12-15T10:57:01Z ----------------------------------------------------------------

It takes 28sec to run the whole notebook, that's eventually a bit too long indeed

a-corni commented 6 months ago

It takes 28sec to run the whole notebook, that's eventually a bit too long indeed

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a-corni commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

dehond commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set $\gamma > 1$ now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

a-corni commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set γ>1 now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

Hey Julius, it's now possible to define $\gamma>1$ ! I have just updated the rates in the notebook (+ shorten a bit the duration of the sequence, change the color of the theoretical curve and fixed a typo) such that the notebook shows the outcome for the rates 0, 0.5, 1.0 and 1.5. Other than that, I think it's okay to merge the PR now, we can always improve it after Christmas :)

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HGSilveri commented on 2023-12-14T10:57:45Z ----------------------------------------------------------------

I can see you cleared the outputs. Isn't this notebook taking a bit too long to run for it to be rerun on every docs build?

a-corni commented on 2023-12-15T10:57:01Z ----------------------------------------------------------------

It takes 28sec to run the whole notebook, that's eventually a bit too long indeed

a-corni commented 6 months ago

It takes 28sec to run the whole notebook, that's eventually a bit too long indeed

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a-corni commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

dehond commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set $\gamma > 1$ now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

a-corni commented 6 months ago

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set γ>1 now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

Hey Julius, it's now possible to define $\gamma>1$ ! I have just updated the rates in the notebook (+ shorten a bit the duration of the sequence, change the color of the theoretical curve and fixed a typo) such that the notebook shows the outcome for the rates 0, 0.5, 1.0 and 1.5. Other than that, I think it's okay to merge the PR now, we can always improve it after Christmas :)

• © Githubissues.
• Githubissues is a development platform for aggregating issues.

[a-corni]

It takes 28sec to run the whole notebook, that's eventually a bit too long indeed

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View entire conversation on ReviewNB

[a-corni]

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

[dehond]

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set $\gamma > 1$ now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

[a-corni]

@dehond Do you have any suggestion about the notebook ? You can preview it here😄

On first sight it looks pretty good to me. Unfortunately I don't have time to review the code now and use it a bit myself. I can do it after Christmas if you'd like, but I can imagine you don't want to wait with the merge until then.

One question that comes up: is it possible to set γ>1 now? I don't think this was possible before since it was interpreted as a probability. If it's a rate this limitation shouldn't exist, and it may be interesting to show it as an example case in one of the plots in the notebook.

Hey Julius, it's now possible to define $\gamma>1$ ! I have just updated the rates in the notebook (+ shorten a bit the duration of the sequence, change the color of the theoretical curve and fixed a typo) such that the notebook shows the outcome for the rates 0, 0.5, 1.0 and 1.5. Other than that, I think it's okay to merge the PR now, we can always improve it after Christmas :)