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Integrated amplitudes

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Anthony Scemama 2023-01-02 16:16:13 +01:00
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@ -943,6 +943,79 @@ power = [
#+end_src
:end:
** Amplitudes (amplitude group)
The wave function may be expressed in terms of action of the cluster
operator $\hat{T}$:
\[
\hat{T} = \hat{T}_1 + \hat{T}_2 + \hat{T}_3 + \dots
\]
on a reference wave function $\Psi$, where $\hat{T}_1$ is the single excitation operator,
\[
\hat{T}_1 = \sum_{ia} t_{i}^{a}\, \hat{a}^\dagger_a \hat{a}_i
\],
$\hat{T}_2$ is the double excitation operator,
\[
\hat{T}_2 = \frac{1}{4} \sum_{ijab} t_{ij}^{ab}\, \hat{a}^\dagger_a \hat{a}^\dagger_b \hat{a}_j \hat{a}_i
\],
/etc/. Indices $i,j,a,b$ denote molecular orbital indices.
Wave functions obtained with perturbation theory of configuration
interaction are of the form
\[ |\Phi\rangle = \hat{T}|\Psi\rangle \]
and coupled-cluster wave functions are of the form
\[ |\Phi\rangle = e^{\hat{T}}| \Psi \rangle \]
The reference wave function is stored using the ~determinant~ and/or
~csf~ groups, and the amplitudes are stored using the current group.
The attributes with the ~exp~ suffix correspond to exponentialized operators.
The order of the indices is chosen such that
- ~t(i,a)~ = $t_{i}^{a}$.
- ~t(i,j,a,b)~ = $t_{ij}^{ab}$,
- ~t(i,j,k,a,b,c)~ = $t_{ijk}^{abc}$,
- ~t(i,j,k,l,a,b,c,d)~ = $t_{ijkl}^{abcd}$,
- $\dots$
#+NAME: amplitude
| Variable | Type | Dimensions | Description |
|-----------------+----------------+-------------------------------------------------------------+-------------------------------------------------|
| ~single~ | ~float sparse~ | ~(mo.num,mo.num)~ | Single excitation amplitudes |
| ~single_exp~ | ~float sparse~ | ~(mo.num,mo.num)~ | Exponentialized single excitation amplitudes |
| ~double~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num)~ | Double excitation amplitudes |
| ~double_exp~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num)~ | Exponentialized double excitation amplitudes |
| ~triple~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num,mo.num,mo.num)~ | Triple excitation amplitudes |
| ~triple_exp~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num,mo.num,mo.num)~ | Exponentialized triple excitation amplitudes |
| ~quadruple~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num,mo.num,mo.num,mo.num,mo.num)~ | Quadruple excitation amplitudes |
| ~quadruple_exp~ | ~float sparse~ | ~(mo.num,mo.num,mo.num,mo.num,mo.num,mo.num,mo.num,mo.num)~ | Exponentialized quadruple excitation amplitudes |
#+CALL: json(data=amplitude, title="amplitude")
#+RESULTS:
:results:
#+begin_src python :tangle trex.json
"amplitude": {
"single" : [ "float sparse", [ "mo.num", "mo.num" ] ]
, "single_exp" : [ "float sparse", [ "mo.num", "mo.num" ] ]
, "double" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num" ] ]
, "double_exp" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num" ] ]
, "triple" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num" ] ]
, "triple_exp" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num" ] ]
, "quadruple" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num" ] ]
, "quadruple_exp" : [ "float sparse", [ "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num", "mo.num" ] ]
} ,
#+end_src
:end:
** Reduced density matrices (rdm group)
The reduced density matrices are defined in the basis of molecular