Critical analysis of a variational method used to describe the molecular electron transport
arXiv:1108.0299 · doi:10.1103/PhysRevB.80.165301
Abstract
In a recent paper [I.\ Bâldea and H.\ Köppel, \prb {\bf 78}, 115315 (2008)], we showed that a variational approach [P.\ Delaney and J.\ C.\ Greer, \prl {\bf 93}, 036805 (2004)] proposed to compute the electron transport through molecules, which is based on boundary constraints of the Wigner function, is unable to correctly describe the zero-bias conductance of the simplest uncorrelated and correlated systems. In the present paper, we extend our previous analysis of the linear response limit of that approach, by considering, instead of the Wigner function, general constraints. We demonstrate that, if, as usual in transport theories, the quasi-particle distributions in electrodes are constrained, this method yields the completely unphysical result that the zero-bias conductance vanishes. Therefore, we conclude that the variational approach itself is defective.
References in corpus (7)
- The numerical renormalization group method for quantum impurity systems
- Real time evolution using the density matrix renormalization group
- Time-step targetting methods for real-time dynamics using DMRG
- Tunnelling in alkanes anchored to gold electrodes via amine end groups
- Independent particle descriptions of tunneling from a many-body perspective
- Nonuniversal transmission phase lapses through a quantum dot: An exact-diagonalization of the many-body transport problem
- On a method to calculate conductance by means of the Wigner function: two critical tests