In the experimental context of cold-fermion optical lattices, we discuss the possibilities to approach the pseudogap or ordered phases by manipulating the scattering length or the strength of the laserinduced lattice potential. Using the Two-Particle Self-Consistent Approach as well as Quantum Monte Carlo simulations, we provide isentropic curves for the two-and three-dimensional Hubbard models at half-filling. These quantitative results are important for practical attempts to reach the ordered antiferromagnetic phase in experiments on optical lattices of two-component fermions. We find that adiabatically turning on the interaction in two dimensions to cool the system is not very effective. In three dimensions, adiabatic cooling to the antiferromagnetic phase can be achieved in such a manner although the cooling efficiency is not as high as initially suggested by Dynamical Mean-Field Theory. Adiabatic cooling by turning off the repulsion beginning at strong coupling is possible in certain cases.

No abstract

No abstract

Based on the non-equilibrium Green's function (NEGF) formalism, we show a numerically efficient method to treat inelastic scattering in multi-dimensional atomistic codes. Using a simple rescaling approach, we detail the calculations of the lowest order approximation (LOA) 1 series to the usual, computationally intensive, self-consistent Born approximation (SCBA). This, combined with the analytic continuation technique of Padé approximants, is applied to an atomistic code based on a tight-binding sp 3 d 5 s * model for electrons and holes, and a modified valence-force-field method for phonons. Currents in Si and Ge gate-all-around nanowire transistors are then computed considering the main crystallographic transport directions ( 100 , 110 , 111 ) for both n-type and p-type devices. Our results show that in most configurations, 3 rd order LOA currents are enough to achieve a high agreement with SCBA results, while reducing the calculation time by about one order. In addition, we propose a criterion to determine the validity of such expansion techniques.