Decoherence of wave packets under inelastic scattering

R. Fong

Time delay is considered in nonrelativistic scattering theory with two-particle inelastic channels present. A comparison method is discussed, which in turn leads to a more natural definition based on the classical definition of time delay for inelastic scattering.

F. Bunchaft, C.M. Chaves, W. Baltensperger

Jean Michel Sellier, Mihail Nedjalkov, Ivan Dimov +1 more

The Wigner formalism is a convenient reformulation of the Schrödinger equation that allows the simulation of transient behavior of quantum systems in the presence of general boundary conditions. Recently, a Wigner Monte Carlo technique, based on particles signs, has been generalized to two-dimensional evolution problems. In this paper, we apply this technique to study the time reversibility of the quantum evolution of a wave packet colliding with a potential wall in the presence of interface roughness, elastic, inelastic, and diffusive interactions with the environment. We show that a wall surface roughness does not necessarily involve time irreversibility. The dynamics of the packet is indeed influenced, but remains coherent, until the boundaries of the system begin to absorb information from the system. Finally, it is shown that in the presence of inelastic scattering or diffusive processes, the time-reversibility of a quantum system is destroyed, whatever the shape of the wall interface is. In particular, we show that the random nature of a process, elastic or inelastic, is responsible for the appearance of quantum decoherence.

C. L. Hammer, Vaughn Stephen Zidell, T. Weber

Yoshimasa Murayama, Masaki Honda

Bayaer Buren, Maodu Chen

Due to the extremely large de Broglie wavelength of cold molecules, cold inelastic scattering is always characterized by the time-independent close-coupling (TICC) method. However, the TICC method is difficult to apply to collisions of large molecular systems. Here, we present a new strategy for characterizing cold inelastic scattering using wave packet (WP) method. In order to deal with the long de Broglie wavelength of cold molecules, the total wave function is divided into interaction, asymptotic and long-range regions (IALR). The three regions use different numbers of ro-vibrational basis functions, especially the long-range region, which uses only one function corresponding to the initial ro-vibrational state. Thus, a very large grid range can be used to characterize long de Broglie wavelengths in scattering coordinates. Due to its better numerical scaling law, the IALR-WP method has great potential in studying the inelastic scatterings of larger collision systems at cold and ultracold regimes.