pairinteraction

Most of the changes in this release are related to simplifying the C++ backend and do not change the python API.

• BasisAtom allow user to set mode how to use the quantum_number_standard_deviations
• backend restructure get_amplitudes, overlaps, matrix elements methods
• in C++ only define one get_matrix_elements method which can calculate matrix elements only betweeen basis objects, but allow different basis
• add the convenience methods get_amplitudes and get_overlaps only in python
• also only in python, allow to calculate matrix elements / amplitudes / overlaps between bases, states and kets (also ket atom tuples for BasisPair)
• overall in python this should now allow to calculate arbitrary amplitudes / overlaps / matrix elements between arbitrary (also different) basis, states and kets
• backend Improve BasisPairCreator with symmetries
• backend Improve database handling of column names
• backend remove unused functions get_rotator and get_ket_for_different_quantum_number_m

• Improve python API
• BasisPair rename from_ket_atoms → from_kets and allow KetPair objects as input
• Implement permutation and inversion symmetry
• Improve state pair label (now shows the actual overlap with the pair of canonical KetAtoms and not the SystemAtom eigenstates)
• Improve EffectiveSystemPair
• Add SystemAtom self interaction via Green Tensor
• Allow arbitrary Green Tensor orientations

• drop support for python 3.9 (since it reached its end of life)
• Major GUI fixes and improvements
• Fix fitting of c3/c6 coefficients in GUI
• improve lifetimes page
• save and restore settings
• calculate the annotation labels just in time
• Improve the GUI theme
• Make pairinteraction launch the gui directly (instead of pairinteraction gui)
• add progress label
• Add a splash screen
• Add new convenience basis constructors BasisAtom.from_kets(kets_of_interest, delta_n=..., ....) and BasisPair.from_ket_atoms(ket_atom_tuples, system_atoms, delta_energy=..., ...)
• Use certifi's CA bundle to make https requests work more robustly

• Fix problems with SSL and handle download errors more gracefully
• Bump C++ Standard from 17 to 23
• Bugfix in effective system pair
• Bugfix in gui two atom export
• Bind identity operator
• Fix sign of C6 coefficient
• A few doc fixes