Speaker
Dr
Alexander Mozeika
(Aalto University)
Description
Equilibrium is a fundamental concept in statistical physics; it
assumes that while the system dynamics is governed by
microscopic interactions, some systems eventually reach a
state where macroscopic observables remain unchanged.
The evolution of many such systems is driven by the
corresponding Hamiltonian energy function and their states
converge to the equilibrium Gibbs-Boltzmann distribution,
from which all macroscopic properties can be computed.
However, the process governing the dynamics of many
other systems cannot be derived from a Hamiltonian; such
systems neither obey detailed balance nor converge to an
equilibrium state. While many real systems, for example in
the financial, social and biological areas, are inherently not
in equilibrium, some of their constituents exhibit
equilibrium-like behaviour in emerging localised or non-
localised domains. Here we show such behaviour in model
systems defined on densely and sparsely connected complex
networks, as they provide a useful representation of many
natural and technological systems. Equilibrium domains are
shown to emerge either abruptly or gradually depending on
the system parameters, for instance temperature, and
disappear, becoming indistinguishable from the remainder of
the system for other parameter values. Consequently, such
domains may exist, under some conditions, within a non-
equilibrium system but may be difficult to identify.
Primary author
Dr
Alexander Mozeika
(Aalto University)
