3 research outputs found
Finite-temperature evaluation of the Fermi density operator
A rational expansion of the Fermi density operator is proposed. This approach
allows to calculate efficiently physical properties of fermionic systems at
finite temperatures without solving an eigenvalue problem. Using N evaluations
of the Green's function, the Fermi density operator can be approximated,
subject to a given precision, in the energy interval from -A to infinity with A
proportional to N. The presented method may become especially useful for
electronic structure calculations involving the calculation of charge
densities.Comment: 6 pages, 4 Postscript figures, submitted to J. Comp. Phy
Quantum transport and momentum conserving dephasing
We study numerically the influence of momentum-conserving dephasing on the
transport in a disordered chain of scatterers. Loss of phase memory is caused
by coupling the transport channels to dephasing reservoirs. In contrast to
previously used models, the dephasing reservoirs are linked to the transport
channels between the scatterers, and momentum conserving dephasing can be
investigated. Our setup provides a model for nanosystems exhibiting conductance
quantization at higher temperatures in spite of the presence of phononic
interaction. We are able to confirm numerically some theoretical predictions.Comment: 7 pages, 4 figure