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/

Zendy Plus

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

Zendy Tools

Zendy Open

We propose a statistical mechanics for a general class of stationary andmetastable equilibrium states. For this purpose, the Gibbs extremal conditionsare slightly modified in order to be applied to a wide class of non-equilibriumstates. As usual, it is assumed that the system maximizes the entropyfunctional $S$, subjected to the standard conditions; i.e., constant energy andnormalization of the probability distribution. However, an extra conservedconstraint function $F$ is also assumed to exist, which forces the system toremain in the metastable configuration. Further, after assuming additivity fortwo quasi-independent subsystems, and that the new constraint commutes withdensity matrix $\rho$, it is argued that F should be an homogeneous function ofthe density matrix, at least for systems in which the spectrum is sufficientlydense to be considered as continuous. The explicit form of $F$ turns to be$F(p_{i})=p_{i}^{q}$, where $p_i$ are the eigenvalues of the density matrix and$q$ is a real number to be determined. This $q$ number appears as a kind ofTsallis parameter having the interpretation of the order of homogeneity of theconstraint $F$. The procedure is applied to describe the results of the plasmaexperiment of Huang and Driscoll. The experimentally measured density ispredicted with a similar precision as it is done with the use of the extremumof the enstrophy and Tsallis procedures. However, the present results definethe density at all the radial positions. In particular, the smooth tail shownby the experimental distribution turns to be predicted by the procedure. Inthis way, the scheme avoids the non-analyticity of the density profile at largedistances arising in both of the mentioned alternative procedures.

A statistical physics of stationary and metastable states: description of the plasma column experimental data