▎ 摘　　要

The effects of collapse and revival of wave packets in monolayer and bilayer graphene in the presence of an external perpendicular magnetic field are investigated. An evolution of the electron wave packets, which are a superposition of states with quantum numbers n near the Landau level n0, are studied. The probability density and the average velocity of the center of packets were calculated analytically and visualized. The initial wave packet, which includes only states with positive energy, loses spatial localization, and splits into several sub-packets at the moments t = (m/n)T-R, where T-R is the revival time, m and n are co-primes. In addition, it is shown that a behavior of the wave packet, which consists of states of two energy bands (with E-n > 0 and E-n < 0) is more complex. Such a packet splits into two parts, which rotate with a cyclotron frequency in opposite directions. The nature of electromagnetic radiation of wave packets, undergoing periodic collapse and revival is discussed. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775356]