Collapsing granular suspensions

A 2D contact dynamics model is proposed as a microscopic description of a collapsing suspension/soil to capture the essential physical processes underlying the dynamics of generation and collapse of the system. Our physical model is compared with real data obtained from in situ measurements performed with a natural collapsing/suspension soil. We show that the shear strength behavior of our collapsing suspension/soil model is very similar to the behavior of this collapsing suspension soil, for both the unperturbed and the perturbed phases of the material.Comment: 7 pages, 5 figures, accepted for publication in EPJ

Effect of the magnetic resonance on the electronic spectra of high-Tc superconductors

We explain recent experimental results on the superconducting state spectral function as obtained by angle resolved photoemission, as well as by tunneling, in high-Tc cuprates. In our model, electrons are coupled to the resonant spin-fluctuation mode observed in inelastic neutron-scattering experiments, as well as to a gapped continuum. We show that, although the weight of the resonance is small, its effect on the electron self-energy is large, and can explain various dispersion anomalies seen in the data. In agreement with the experiment, we find that these effects are a strong function of doping. We contrast our results to those expected for electrons coupled to phonons