We analyse several non-Hermitian Hamiltonians with antiunitary symmetry from the point of view of their point-group symmetry. It enables us to predict the degeneracy of the energy levels and to reduce the dimension of the ...

The 2008 Nobel prize of physics pay tribute to three theoretical physicist by their work related to some symmetries of Nature. We briefly comments the importance of these works and the context in which they were done. ...

We present a detailed analysis of nonempirically tuned range-separated functionals, with both short- and long-range exchange, for calculating the static linear polarizability and second hyperpolarizabilities of various ...

We discuss a parity-time (PT) symmetric Hamiltonian with complex eigenvalues. It is based on the dimensionless Schrödinger equation for a particle in a square box with the PT-symmetric potential V(x, y) = iaxy. Perturbation ...

DFT broken-symmetry calculations at the B3LYP level were carried out to evaluate the exchange coupling constants defined by the Heisenberg-Dirac-van Vleck spin Hamiltonian (HDvV), Ĥ = -2JŜaŜb, in a 1D chain of iron basic ...