  That of disequilibrium (D) is a statistical notion introduced by
L\'opez-Ruiz, Mancini, and Calbet (LMC) more than 20 years ago [Phys. Lett. A
209 (1995) 321]. D measures the amount of correlational structure of a system.
We wish to use D to analyze one of the simplest types of quantum correlations,
those present in simple quantum gaseous systems and due to symmetry
considerations. To this end we extend the LMC formalism to the grand canonical
environment and show that D displays distinctive behaviors for simple gases,
that allow for interesting insights into their structural properties.
