A microscopic rotational cranking model and its connection to conventional cranking and other collective rotational models

TL;DR

This paper introduces a microscopic rotational cranking model (MCRM) that unifies and extends conventional and other collective rotational models in nuclear physics, accounting for intrinsic motion and collective flows.

Contribution

The paper derives a new MCRM that incorporates both rigid and irrotational flows, connecting it to existing models and highlighting its broader applicability.

Findings

MCRM reduces to CCRM when irrotational flow is absent.

The MCRM includes a cranking Coriolis energy term linear in angular momentum.

The model can be related to particle-plus-rotor and collective rotation-vibration models.

Abstract

A microscopic time-reversal invariant cranking model (MCRM) for nuclear collective rotation about a single axis and its coupling to intrinsic motion is derived. The MCRM is derived by transforming the stationary nuclear Schrodinger equation using a collective rotation-intrinsic product wavefunction, imposing no constraints on the wavefunction and the nucleon coordinates, and using no relative co-ordinates. The derivatives of the collective-rotation angle are defined in terms of a combination of rigid and irrotational collective flows of the nucleons. The collective wavefunction is chosen to be an eigenstate of the angular momentum, yielding a MCRM Schrodinger equation for the intrinsic wavefunction that contains a cranking Coriolis energy term that is linear in the angular momentum and shear operators, a collective centrifugal energy term, and a rotation-fluctuation energy term. In absence of the irrotational-flow component and fluctuation energy term, the MCRM equation reduces to that of the conventional cranking model (CCRM), but with a dynamic rigid-flow angular velocity and rigid-flow centrifugal-energy term. The expectation of the angular momentum operator, which is the sum of the collective rotation angular momentum and the expectation of the angular momentum in the intrinsic state, would reduce to that in the CCRM if the collective rotation angular momentum were small. However, it is shown that, even for the simple case of the anisotropic harmonic oscillator mean-field potential in , the collective rotation angular momentum is not small in the current version of the MCRM, and that this problem needs further study. It is also shown that the MCRM Schrodinger equation is reducible to the equations of the particle-plus-rotor, phenomenological and microscopic collective rotation-vibration, and two-fluid semi-classical collective models.