Time Arrow in Wave-Packet Evolution
摘要
Availability of short, femtosecond laser pulses has recently made feasible the probing of phases in an atomic or molecular wave-packet (superposition of energy eigenstates). With short duration excitations the initial form of the wave-packet is an essentially real "doorway state", and this develops phases for each of its component amplitudes as it evolves. It is suggested that these phases are hallmarks of a time arrow and irreversibility that are inherent in the quantum mechanical processes of preparation and evolution. To display the non-triviality of the result, we show under what conditions it would not hold; to discuss its truth, we consider some apparent contradictions. We propose that (in time-reversal invariant systems) the preparation of "initially" complex wave-packets needs finite times to complete, i.e., is not instantaneous.
引用
@article{arxiv.cond-mat/0007142,
title = {Time Arrow in Wave-Packet Evolution},
author = {Robert Englman and Asher Yahalom},
journal= {arXiv preprint arXiv:cond-mat/0007142},
year = {2016}
}
备注
15 pages, Latex, to appear in Foundations of Phys. Lett. (2000)