Collective inertia of Nambu-Goldstone mode from linear response theory

Background: Spurious zero-energy Nambu-Goldstone (NG) modes appear when the symmetry of a system is spontaneously broken. The Thouless-Valatin inertia, the collective inertia of the NG mode, contains important information concerning collective motion. Purpose: To establish an efficient and precise method for deriving the collective inertia and the conjugate operator of a NG mode, we derive an expression for the response function in terms of the coordinate-momentum representation of the quasiparticle random-phase approximation which is valid even if a symmetry-restoring zero-energy mode is present. Methods: We use the finite amplitude method for computing the response function of superfluid nuclei with the nuclear density functional theory. Results: We derived analytically the collective inertia and the conjugate coordinate operator of the NG mode from the zero-energy linear response with the momentum operator of the NG mode. The formulation is tested in the cases of translational and pairing rotational modes. Illustrative calculations are performed for the neutron pairing rotation in Sn isotopes, the proton pairing rotation in N = 82 isotones, and the neutron and proton pairing rotations around the 130Xe nucleus. Conclusions: The proposed formulation allows us to compute the collective inertia of the NG mode precisely and efficiently. The conjugate coordinate operator can be utilized to remove spurious contributions to the strength distribution in the finite amplitude method.Comment: 14 pages, 6 figures, 1 table, submitted to Phys. Rev.

電子-多価イオン衝突における二電子性再結号過程の高分解能X線分光測定

電気通信大学200

Pairing Nambu-Goldstone Modes within Nuclear Density Functional Theory

We show that the Nambu-Goldstone formalism of the broken gauge symmetry in the presence of the $T=1$ pairing condensate offers a quantitative description of the binding-energy differences of open-shell superfluid nuclei. We conclude that the pairing-rotational moments of inertia are excellent pairing indicators, which are free from ambiguities attributed to odd-mass systems. We offer a new, unified interpretation of the binding-energy differences traditionally viewed in the shell model picture as signatures of the valence nucleon properties. We present the first systematic analysis of the off-diagonal pairing-rotational moments of inertia and demonstrate the mixing of the neutron and proton pairing-rotational modes in the ground states of even-even nuclei. Finally, we discuss the importance of mass measurements of neutron-rich nuclei for constraining the pairing energy density functional.Comment: 6 pages, 3 figure

青葉山周辺から産する鉱物標本の産出層準－ 仙台地域の地学教材の基礎資料 －

Mineral specimens occurring around the Aobayama Hill have been utilized as scientific study objects, also as familiar geology-teaching materials in the Sendai area. We investigate the background geology of their occurrences including stratigraphic horizons, depositional conditions, and radiometric age. Large crystals of anorthite and augite, originally produced as crystal bombs of volcanic eruptions, are collected from a tuff breccia bed of the lowest part of Upper Miocene Mitaki Formation which unconformably covers the Nashino Formation.Large pseudomorph specimens of high-quartz are obtained from matrix-supported conglomerate, tufffaceous sandstone or pebble-containing mudstone beds, which strata overlie the Mitaki Formation. Zircon grains from the high-quartz horizon are dated to 8.0±0.7 Ma as fission-track age by the LA-ICP-MS method combined with the U-Pb dating. The strata including high-quartz horizon beds, often showing chaotic or dipping, are covered by a flat bed of clast-supported conglomerate underlying the Pliocene Tatsunokuchi Formation. They belong not to the Pliocene Kameoka Formation as a conventional thought, but probably to the Upper MioceneShirasawa Formation or the upper part of Nashino Formation, which two formations have been regarded as contemporaneous to the Mitaki Formation. Possibly, high-quartz have been derived from pumice tuff of the Nashino Formation which had been exposed in adjacent area at that time

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