“time Arrow” in Wave-Packet Evolution
Source: Foundations of Physics Letters, Volume 13, Number 4, August 2000 , pp. 329-343(15)
Abstract: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.
Document Type: Regular Paper
Affiliations: 1: College of Judea and Samaria, Ariel 44284, Israel; Department of Physics and Applied Mathematics, Soreq NRC, Yavne 81810, Israel 2: College of Judea and Samaria, Ariel 44284, Israel; Faculty of Engineering, Tel-Aviv University, Tel-Aviv 69978, Israel. email@example.com, firstname.lastname@example.org
Publication date: August 1, 2000