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Using a density-functional approach, we calculate the principal vibrational spectra of vitreous SiO2 and vitreous GeO2 and discuss their analogies and differences. For both glasses, we generate model structures consisting of a random network of corner-shar ...
Using both exact diagonalizations and diagonalizations in a subset of short-range valence-bond singlets, we address the nature of the groundstate of the Heisenberg spin-1∕2 antiferromagnet on the square lattice with competing next-nearest and next-next-nea ...
Motivated by the ever-increasing experimental effort devoted to the properties of frustrated quantum magnets in a magnetic field, we present a careful and detailed theoretical analysis of a one-dimensional version of this problem, a frustrated ladder with ...
Frustrated quantum magnets are a real challenge to theorists because standard analytical and numerical methods fail in most cases. Significant progress has been recently achieved however on the basis of what one may call minimal models, i.e. models which k ...
There has been an extensive interest in cryst. solids contg. magnetic nanostructures. The chem. systems that we have paid special attention to thus far in our lab. include transition-metal-contg. oxy compds., such as silicates, phosphates and arsenates. Th ...
Electronic structure changes are at the origin of the making, breaking and transformation of bonds. These changes can be visualized by measuring the geometric structure in "real-time" during the course of a chemical reaction, a biological function or a phy ...
The spin transfer torque model applied in the context of a Fokker-Planck analysis (Li and Zhang 2004 Phys. Rev. B 69 134416) is shown to account for a complete set of statistical data for switching times obtained with pseudo spin-valves (Fabian et al 2003 ...
Inelastic neutron scattering, susceptibility, and high-field magnetization identify LiCuVO4 as a nearest-neighbour ferromagnetic, next-nearest-neighbour frustrated, quasi-one-dimensional helimagnet, which is largely influenced by quantum fluctuations. Comp ...
This work aims at a better understanding of transport mechanisms which take place in organic semiconductors such as pentacene. More accurately, we believe that the electronic polarization plays a leading part, which we try to identify in the particular cas ...
Starting from the mean-field solution of a spin-orbital model of LiNiO2, we derive an effective quantum dimer model (QDM) that lives on the triangular lattice and contains kinetic terms acting on four-site plaquettes and six-site loops. Using exact diagona ...
