  We find a new phenomenon, a particle like an electron, which transfers
kinetic energy to other subject undergoes a decrease in its wave packet size in
space and an electron that gains kinetic energy experiences an enlargement of
its wavepacket size. This effect occurs in some amount of degree almost in any
physical system. The effect has significance on electron transport in
semiconductors, quantum wires, future devices in nanotechnology and quantum
optics.

Mesoscale and Nanoscale Physics;Quantum Physics