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Wave packet dynamics for a system in the quantum well with one moving wall

DE-HUA WANG1,* , HUA WANG2, HAI-FENG MU3, TONG SHI1, XIN-YUE SUN3, Gang ZHAO3, QIN-FENG XU3

Affiliation

  1. School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China;
  2. Department of Electronic Engineering, Yantai Automobile Engineering Professional College, Yantai 265500, China
  3. School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China

Abstract

The time evolution of the wave function provides a beautiful insight into the wave packet dynamics in the quantum theory. In this work, we study the wave packet dynamics of a particle inside a quantum well with one moving wall. Since one wall is moving with time, the eigen wave function and eigen energy of this system are time-dependent, which makes the time evolution of the wave packet in this system become much more complicated and interesting compared to the case in a quantum well with two static walls. It is shown when the wall is moving very slowly, fractional revival phenomenon of wave packet is shown to exist, but the full revival of the wave packet at one revival time is disappeared. With the increase of the moving speed of one wall, a peculiar revival pattern occurs, the center of the revival peak will shift accompanied by the motion of the wall, the wave function can not “clone” its initial wave function at all. Revivals are observed at some special decimal fractions of the revival time instead of rational fractions of the revival time appeared in the case of the static quantum well. Additionally, the initial momentum of the Gaussians wave packet can also affect the wave packet evolution and the autocorrelation of this system. The probability density distribution and the autocorrelation of this system are nearly unaffected for Guassian with an initial momentum smaller than the wall motion. However, when the initial momentum of the Gaussians wave packet is larger than the wall motion, the amplitude in the probability density gets decreased, but the oscillatory structures become complicated; the interval between the adjacent revival peaks in the autocorrelation function decreases with the initial momentum. The non-periodic revival pattern observed in this work can be considered as a consequence of the moving wall effect. We hope that our work can guide the future experimental study of the wave packet dynamics in the presence of a moving boundary.

Keywords

Wave packet dynamics, Quantum well, Moving wall.

Submitted at: Dec. 21, 2018
Accepted at: June 14, 2019

Citation

DE-HUA WANG, HUA WANG, HAI-FENG MU, TONG SHI, XIN-YUE SUN, Gang ZHAO, QIN-FENG XU, Wave packet dynamics for a system in the quantum well with one moving wall, Journal of Optoelectronics and Advanced Materials Vol. 21, Iss. 5-6, pp. 343-356 (2019)