2014/05/31 by Sean A. Hartnoll · 2 citations
Physics and Astronomy · #cond-mat.str-el #hep-th
paper · pdf · doi:10.1038/nphys3174
1+17 pages + references. 2 figures, v2 minor improvements to discussion, v3 improved presentation and discussion
arxiv created 2014/07/24 · arxiv updated 2015/06/19
In an incoherent metal, transport is controlled by the collective diffusion of energy and charge rather than by quasiparticle or momentum relaxation. We explore the possibility of a universal bound D \gtrsim ℏ vF2/(kB T) on the underlying diffusion constants in an incoherent metal. Such a bound is loosely motivated by results from holographic duality, the uncertainty principle and from measurements of diffusion in strongly interacting non-metallic systems. Metals close to saturating this bound are shown to have a linear in temperature resistivity with an underlying dissipative timescale matching that recently deduced from experimental data on a wide range of metals. This bound may be responsible for the ubiquitous appearance of high temperature regimes in metals with T-linear resistivity, motivating direct probes of diffusive processes and measurements of charge susceptibilities.