Momentum spread: Amplitude and current contributions

Paul E. Sokol, Richard N. Silver, J. W. Clark

Anthony Allan Villanueva

A quantum particle (represented by a Gaussian wave packet) under uniform gravity, projected upward (the conventional positive direction) along the vertical degree of freedom x, may have a negative probability current on a set of points q. This imposes the condition that the position and momentum observables of the state are negatively correlated. We calculate the effect of the negative correlation on the individual contributions to the probability current by the positive and negative momentum amplitudes of the state using an integral representation of the probability current. Negative position-momentum correlation causes a transient attenuation of all contributions to the probability flow, and wave packet spreading is temporarily mitigated.

Scott E. Hoffmann

We find the laws for the spreading of the spatial widths (parallel and transverse to the direction of average motion) of the relativistic position probability density for a massive, spinless particle. We find that when the momentum width of the wavepacket is small compared to the average momentum, there is a long time over which spreading is minimal. This result may be useful in particle accelerator design. We also demonstrate the Lorentz contraction of a wavepacket using relativistic probability amplitudes.

Howard Brenner, David A. Edwards

Zhongjie Wang, Lu Yi-Qun, Lu Tongxing +1 more

In this paper the model of two-level atomic momentum spread in amplitude-modulated standing light wave was investigated.This model shows chaotic behaviour in the classical limit.The system displays the characteristic of dynamical localization for the same parameters as those in the classical model correspoinding to it.