Efficient linear scaling mapping for permutation symmetric Fock spaces

Numerically solving a second quantised many-body model in the permutation symmetric Fock space can be challenging for two reasons: (i) an increased complication calculations of matrix elements various operators, and (ii) poor scaling cost these with size. We present method that solves both problems. find mapping used to simplify elements. The is directly generated so its computational scales only linearly size negligible even large enough sizes approach thermodynamic limit. A fortran implementation as library – FockMap provided along test program. Program Title: CPC Library link program files: https://doi.org/10.17632/7srkkv3fm2.1 Licensing provisions: GPLv3 Programming language: FORTRAN Nature problem: Solving models space. Solution method: between states exists calculate operators. pattern found generated.