quantnbody 1.0.1

A python package for quantum chemistry/physics to manipulate many-body operators and wave functions.

QuantNBody : a python package for quantum chemistry/physics to manipulate many-body operators and wave functions.

QuantNBody is dedicated to the manipulation of quantum N-body systems ranging from many-electron to many-bosons hamiltonians. It provides a quick and easy way to build many-body operators and get access (in a few python lines) to important quantities/objects such as :

• The decomposition of a wavefunction in a many-body basis
• The 1-body, 2-body (...) reduced density matrices (espressed in the Molecular orbital or spinorbital basis)
• The spin operators S^2, S_z (for fermionic system expressed in a many-body basis)
• ...

Hamiltonians already implemented:

• Ab initio electronic structure Hamiltonian (needs psi4 or PySCf to provide the electronic integrals)
• Fermi-Hubbard molecules Hamiltonians ( parameters given by the user )
• Bose-Hubbard Hamiltonians ( parameters given by the user )

Methods one can implement from scratch with the tools from QuantNBody (see the Example folder):

• FCI : Full Configuration Interaction
• CAS-CI : Complete Active Space CI
• SA-CASSCF : State-Averaged CAS Self-Consistent Field (with orbital optimization)
• ...