Prog. Theor. Phys. Vol. 80 No. 4 (1988) pp. 678-693

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Extraction of Dynamical Collective Subspace for Large-Amplitude Collective Motion

— Application to Simple Solvable Model —

Kazuhiro Muramatsu, Fumihiko Sakata and Toshio Marumori^*

Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188
^*Institute of Physics, University of Tsukuba, Tsukuba 305

(Received March 18, 1988)

Abstract:

It is the purpose of the present paper to illustrate the quantum theory of dynamical collective subspace, which has been proposed in a previous paper to describe the large-amplitude collective motion, by using a simple four-level model with the pairing interactions. The quantum theory provides us a prescription to dynamically specify a set of "global" collective operators as well as the "optimum" dynamical collective subspace spanned by them. This prescription is applied to the simple model, and the results thus obtained are compared with exact numerical solutions. It is shown that the results by our theory are in excellent agreement with the exact solutions, not only in the low-lying collective states in the vicinity of the "vacuum" with the stable mean-field but also in the higher excited collective states far from it. Through the investigation, it is demonstrated that our theory is quite powerful in disclosing microscopic structure of transfiguration of collectivity near the critical point of the "phase transition". It is the essential statement derived by our theory that the conventional (local) collective operators based on the Tamm-Dancoff approximation or the random phase approximation should be replaced by relevant (global) collective operators with changeable microscopic structure depending on the amplitude of collective motion, in order to properly specify a set of collective excited states.

URL : http://ptp.ipap.jp/link?PTP/80/678/
DOI : 10.1143/PTP.80.678

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Citing Article(s) :

Progress of Theoretical Physics Vol. 82 No. 5 (1989) pp. 965-987 :
Breking of Separability Condition for Dynamical Collective Subspace

Fumihiko Sakata, Yoshifumi Yamamoto, Toshio Marumori, Shinji Iida and Hidehiko Tsukuma
Progress of Theoretical Physics Vol. 85 No. 6 (1991) pp. 1235-1270 :
Microscopic Description of Nuclear Collective Rotation by Means of the Self-Consistent Collective Coordinate Method

Jun Terasaki, Toshio Marumori and Fumihiko Sakata