Gauge symmetry in large-amplitude collective motion of superfluid nuclei

by Dr Koichi Sato (RIKEN Nishina Center)

Monday 29 Feb 2016, 13:00 → 14:00 Asia/Tokyo

Main Research Building 433 (RIKEN Wako)

Date: Feb 29 (Mon) Time: 13:00 - Place: Main Research bldg. 433 Speaker: Koichi Sato (RIKEN, Nishina Center for Accelerator-Based Science) Title: Gauge symmetry in large-amplitude collective motion of superfluid nuclei Abstract: Construction of a microscopic theory of large-amplitude collective motion of atomic nuclei is one of the long-standing open problems in nuclear physics. The adiabatic self-consistent collective coordinate (ASCC) method [1] is a practical method for describing the large-amplitude collective motion in atomic nuclei with superfluidity and an advanced version of the adiabatic time-dependent Hartree-Fock-Bogoliubov theory. In solving the basic equations of the ASCC method, Hinohara et al. [2] encountered a numerical instability and found that it was caused by some symmetry of the basic equations under a certain continuous transformation (“gauge” transformation) which mixes the collective coordinate and particle number operators. In this talk, after introducing some applications of the ASCC method, I discuss the gauge symmetry in the ASCC method on the basis of the theory of constrained systems, which was initiated by Dirac and Bergmann [3]. The gauge symmetry in the ASCC method originates from the constraint on the particle number in the collective Hamiltonian, and it is partially broken by the adiabatic expansion. The validity of the adiabatic expansion under the general gauge transformation is also discussed. [1] M. Matsuo, T. Nakatsukasa, K. Matsuyanagi, Prog. Theor. Phys. 103 (2000) 959. [2] N. Hinohara, T. Nakatsukasa, M. Matsuo, K. Matsuyanagi, Prog. Theor. Phys. 117 (2007) 451. [3] K. Sato, Prog. Theor. Exp. Phys. (2015) 123D01. See more QHP seminars