Quantum Circuits for the Preparation of Spin Eigenfunctions on Quantum Computers

The application of quantum algorithms to the study many-particle systems requires ability prepare wavefunctions that are relevant in behavior system under study. Hamiltonian symmetries an important instrument, classify wavefunctions, and improve efficiency numerical simulations. In this work, circuits for exact approximate preparation total spin eigenfunctions on computers presented. Two different strategies discussed compared: recursive construction based addition theorem angular momentum, heuristic approximation variational optimization a suitable cost function. these is illustrated detail, demonstrated IBM devices, focusing 3- 5-spin graphs with triangle connectivity.