Transition from collective to single-particle regime in a quantum fluid

Kit-Keung Kan

V. Apaja

Kit-Keung Kan, James J. Griffin

The problem of a single quantal particle moving in a time-dependent external potential well is formulated specifically to emphasize and develop the fluid dynamical aspects of the matter flow. This idealized problem, the single-particle Schr\"odinger fluid, is shown to exhibit already a remarkably rich variety of fluid dynamical features, including compressible flow and line vortices. It provides also a sufficient framework to encompass simultaneously various simplified fluidic models for nuclei which have earlier been postulated on an ad hoc basis, and to illuminate their underlying restrictions. Explicit solutions of the single-particle Schr\"odinger fluid problem are studied in the adiabatic limit for their mathematical and physical implications (especially regarding the collective kinetic energy). The basic generalizations for extension of the treatment to the many-body Schr\"odinger fluid are set forth.NUCLEAR STRUCTURE Fluid dynamical formulation of quantum mechanics, single-particle behavior in nuclear collective motion, fission and heavy-ion collision, inertial parameter, adiabatic approximation.

亮五 久保, 文彦 高野

Alessio Zaccone, Kostya Trachenko

For a system to qualify as a quantum fluid, quantum-statistical effects should operate in addition to quantum-mechanical ones. Here, we address the hitherto unexplored dynamical condition for the quantum-statistical effects to be manifested, and consider particle exchange events in the gaslike regime of fluid dynamics as a dynamical process with an intrinsic time scale. We subsequently propose a quantitative criterion of particle indistinguishability and associated quantum statistics to be inoperative at short time and emerge at long time. Experimentally verifiable, our predictions enable a systematic search for a transition between statistics-active and statistics-inactive regimes in quantum fluids.