English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The effects of the propagation of particles which have a finite life-time andan according width in their mass spectrum are discussed in the context oftransport descriptions. In the first part the coupling of soft photon modes toa source of charged particles is studied in a classical model which can besolved completely in analytical terms. The solution corresponds to are-summation of certain field theory diagrams. The general properties of broadresonances in dense finite temperature systems are discussed at the example ofthe $\rho$-meson in hadronic matter. The second part addresses the problem oftransport descriptions which also account for the damping width of theparticles. The Kadanoff--Baym equation after gradient approximation togetherwith the $\Phi$-derivable method of Baym provides a self-consistent andconserving scheme. Memory effects appearing in collision term diagrams ofhigher order are discussed. We derive a generalized expression for thenonequilibrium kinetic entropy flow, which includes corrections fromfluctuations and mass-width effects. In special cases an $H$-theorem is proved.Memory effects in collision terms provide contributions to the kinetic entropyflow that in the Fermi-liquid case recover the famous bosonic type $T^3 \ln T$correction to the specific heat of liquid Helium-3.Comment: Contribution to Proc. of Int. Workshop "Kadanoff-Baym Equations -  Progress and Perspectives for Many-Body Physics" Rostock (Germany), September  20-24 1999, ed. M.Bonitz, World Scientific (2000

SOFT MODES, QUANTUM TRANSPORT AND KINETIC ENTROPY