Is second law of thermodynamics violated in 2D Yukawa liquids?

Large micron-sized grains when immersed in a conventional low temperature plasmas tends to acquire large value of negative charge while simultaneously shielded by the plasma. Neutrals in the medium may be used to control the average temperature of the grain medium. Thus grain-grain interaction takes place via a shielded Coulomb interaction or a Yukawa interaction. When the grain temperature is reduced, the grain medium behaves like a liquid One of the basic advantage of such experiments is that the grain dynamics is tractable by naked eye or by using standard cameras and their instantaneous positions and velocities can be measured in-situ. This situation is favorable to ask fundamental questions at particle level. Using Molecular dynamics simulation method, we investigate various fundamental questions related to non-equilibrium statistical mechanics of Yukawa liquids. For example, when subject to external temperature gradient and gravity, it has been demonstrated that Yukawa liquids form Rayleigh-Benard convection cells. Does this driven-dissipative structure obey second law of thermodynamics which states that entropy of a system is either constant or ever increasing? Or are there events with negative entropy production rate which temporarily violate the second law? We demonstrate these systems indeed violate the second law of thermodynamics at certain scales. Details of this work will be brought out in this presentation. (author)