An impurity bond J ′ in a periodic 1D antiferromagnetic, spin 1 chain with exchange J is considered. Using the numerical density matrix renormalization group method, we find an impurity energy level in the Haldane gap, corresponding to a bound state near the impurity bond. When J ′ < J the level changes gradually from the edge of the Haldane gap to the ground state energy as the deviation dev =...

As an increased number of measures (Swiss or European level) aim at developing more sustainable policies for energy management and reduction of CO2 emissions in particular (for example, the 3x20 policy), very few tools currently exist at the regional/cantonal level to monitor the multiple existing energy flows. Energy issues at local and territorial level have become considerably more complex i...

Today's champion organic (opto-)electronic devices comprise an ever-increasing number of different organic-semiconductor layers. The functionality of these complex heterostructures largely derives from the relative alignment of the frontier molecular-orbital energies in each layer with respect to those in all others. Despite the technological relevance of the energy-level alignment at organic h...