Hello, there seems to be a slight error in sample 2.1

[shuailiu199966]

Hello, I have three questions.
Based on the code in sample 2.1, the entropy value that I obtained is negative and it is the same for all models.
Can the Python script you provided be used for calculations on all models？
How should I calculate the average bond density（W_p）?

[shuailiu199966]

[tmisawa]

This problem is caused by the fact that the entropy has degrees of freedom in constant shifts. In this calculation, the high-temperature limit of entropy is set to zero
and the zero-temperature limit of the entropy is -log(d_H), where d_H is the dimensions of the Hilbert space. For example, if you take the 12-site spin 1/2 model, d_H is given by 2^{12}. In that case, the entropy converges to -log(2^12)~ -8.3177 at the zero-temperature limit. If you want to set S(T=0)=0, please add log(d_H) to the calculation results.

[shuailiu199966]

 If I set L=2 and W=3 for the 2D kaitev model under the standard model, then should d_H be 2 ^ {6} or 2 ^ {12}? What other parameters should I change   ------------------ Original ------------------ From: ***@***.***>; Date:  Tue, May 14, 2024 03:36 PM To: ***@***.***>; Cc: ***@***.***>; ***@***.***>; Subject:  Re: [issp-center-dev/HPhi] Hello, there seems to be a slight error in sample 2.1 (Issue #163)   This problem is caused by the fact that the entropy has degrees of freedom in constant shifts. In this calculation, the high-temperature limit of entropy is set to zero and the zero-temperature limit of the entropy is -log(d_H), where d_H is the dimensions of the Hilbert space. For example, if you take the 12-site spin 1/2 model, d_H is given by 2^{12}. In that case, the entropy converges to -log(2^12)~ -8.3177. If you want to set S(T=0)=0, please add log(d_H) to the calculation results. — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.Message ID: ***@***.***>

[tmisawa]

In that case, d_H=2^12. You can find the information of d_H in standard output by HPhi.
For example, MAX DIMENSION idim_max=4096. Here, idim_max means d_H.

[tmisawa]

You can also find information of idim_max in output/CHECK_Memory.dat.

[tmisawa]

How should I calculate the average bond density（W_p）?

Does W_p mean the flux of the Kitaev model? If so, it is possible to calculate W_p.
Since W_p is defined by the product of six spin operators, i.e., W_p=Sx*Sy*Sz*Sx*Sy*Sz,
it is necessary to an input file for calculating six-body Green functions.
Please note that SixBodyG is the keyword for specifying the six-body Green functions in calmod.def .

[tmisawa]

Yes. This formula can be used for any other model, such as the Kitaev model. This factor comes from the normalization of wave functions and does not relate to lattice geometry.