5,059 research outputs found
The standard map: From Boltzmann-Gibbs statistics to Tsallis statistics
As well known, Boltzmann-Gibbs statistics is the correct way of
thermostatistically approaching ergodic systems. On the other hand, nontrivial
ergodicity breakdown and strong correlations typically drag the system into
out-of-equilibrium states where Boltzmann-Gibbs statistics fails. For a wide
class of such systems, it has been shown in recent years that the correct
approach is to use Tsallis statistics instead. Here we show how the dynamics of
the paradigmatic conservative (area-preserving) standard map exhibits, in an
exceptionally clear manner, the crossing from one statistics to the other. Our
results unambiguously illustrate the domains of validity of both
Boltzmann-Gibbs and Tsallis statistics
Spin projection chromatography
We formulate the many-body spin dynamics at high temperature within the
non-equilibrium Keldysh formalism. For the simplest XY interaction, analytical
expressions in terms of the one particle solutions are obtained for linear and
ring configurations. For small rings of even spin number, the group velocities
of excitations depend on the parity of the total spin projection. This should
enable a dynamical filtering of spin projections with a given parity i.e. a
Spin projection chromatography.Comment: 13 pages, 3 figure
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