Density and current response functions in strongly disordered electron systems: Diffusion, electrical conductivity and Einstein relation
| dc.creator | Janis, V. | |
| dc.creator | Kolorenc, J. | |
| dc.creator | Spicka, V. | |
| dc.date | 2002-03-20 | |
| dc.date | 2003-01-03 | |
| dc.date.accessioned | 2026-07-07T10:02:55Z | |
| dc.date.available | 2026-07-07T10:02:55Z | |
| dc.description | We study consequences of gauge invariance and charge conservation of an electron gas in a strong random potential perturbed by a weak electromagnetic field. We use quantum equations of motion and Ward identities for one- and two-particle averaged Green functions to establish exact relations between density and current response functions. In particular we find precise conditions under which we can extract the current-current correlation function from the density-density correlation function and vice versa. We use these results in two different ways to extend validity of a formula associating the density response function with the electrical conductivity from semiclassical equilibrium to quantum nonequilibrium systems. Finally we introduce quantum diffusion via a response relating the current with the negative gradient of the charge density. With the aid of this response function we derive a quantum version of the Einstein relation and prove the existence of the diffusion pole in the zero-temperature electron-hole correlation function with the the long-range spatial fluctuations controlled by the static diffusion constant. | |
| dc.description | 16 pages, REVTeX4, 6 EPS figures | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0203414 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0203414 | |
| dc.identifier | Eur. J. Phys. B 35 (2003) 77 | |
| dc.identifier | doi:10.1140/epjb/e2003-00258-4 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/169141 | |
| dc.subject | Disordered Systems and Neural Networks | |
| dc.subject | Strongly Correlated Electrons | |
| dc.title | Density and current response functions in strongly disordered electron systems: Diffusion, electrical conductivity and Einstein relation | |
| dc.type | text |