Abstract:  In classical systems, when the volume occupied by a free particle expands, positive work is always done on the surroundings. However, under the same conditions, the expansion of a quantum system does not necessarily result in positive work; this depends on the speed of the expansion. This paper explores the characteristics of the work output during the finite uniform expansion of the walls of an infinite potential well. The calculations show that the faster the walls of the potential well move, the smaller the total work output.

Key words:  quantum system, infinite potential well, output work