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arXiv · 1611.06623

Influence of Nambu-Goldstone mode on energy-weighted sum of excitation strengths in random-phase approximation

H. Nakada
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Abstract

Influence of the Nambu-Goldstone (NG) mode on the energy-weighted sum (EWS) of the excitation strengths is analyzed, within the random-phase approximation (RPA). When a certain symmetry is broken at the mean-field level, a NG mode emerges in the RPA, which can be represented by canonical variables forming a two-dimensional Jordan block. A general formula is rederived which separates out the NG-mode contribution to the EWS, via the projection on the subspace directed by the NG mode. As examples, the formula is applied to the $E1$ excitation and the rotational excitations in nuclei, further confirming theoretical consistency of the RPA.

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H. Nakada. 2017-01-11. Influence of Nambu-Goldstone mode on energy-weighted sum of excitation strengths in random-phase approximation. https://doi.org/10.1093/ptep%2Fptx004

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