45 citations · 58 across the 7 of their papers we have counts for
7 papers
A multiplet analysis of spectra in the presence of broken symmetries
Jan Naudts, Tobias Verhulst
We introduce the notion of a generalised symmetry M of a hamiltonian H. It is a symmetry which has been broken in a very specific manner, involving ladder operators R and R*. In Th…
A mechanism for pair formation in strongly correlated systems
Tobias Verhulst, Jan Naudts
We start from a Hamiltonian describing non-interacting fermions and add bosons to the model, with a Jaynes-Cummings-like interaction between the bosons and fermions. Because of the…
Electron pair forming in an integrable model
Jan Naudts, Tobias Verhulst
We consider a lattice model in which phonons scatter with pairs of electrons. All eigenvalues and eigenvectors can be obtained analytically. For a suitable choice of parameters the…
Analysis of the N=4 Hubbard ring using a counting operator
Tobias Verhulst, Ben Anthonis, Jan Naudts
We prove three theorems about the use of a counting operator to study the spectrum of model Hamiltonians. We analytically calculate the eigenvalues of the Hubbard ring with four la…
Counting operator analysis of the discrete spectrum of some model Hamiltonians
Jan Naudts, Tobias Verhulst, Ben Anthonis
The first step in the counting operator analysis of the spectrum of any model Hamiltonian H is the choice of a Hermitean operator M in such a way that the third commutator with H i…
Ensemble averaged entanglement of two-particle states in Fock space
Jan Naudts, Tobias Verhulst
Recent results, extending the Schmidt decomposition theorem to wavefunctions of identical particles, are reviewed. They are used to give a definition of reduced density operators i…