  We show that an adiabatic cycle excites Bose particles confined in a
one-dimensional box. During the adiabatic cycle, a wall described by a
$\delta$-shaped potential is applied and its strength and position are slowly
varied. When the system is initially prepared in the ground state, namely, in
the zero-temperature equilibrium state, the adiabatic cycle brings all bosons
into the first excited one-particle state, leaving the system in a
nonequilibrium state. The absorbed energy during the cycle is proportional to
the number of bosons.
