268 research outputs found
Luttinger-volume violating Fermi liquid in the pseudogap phase of the cuprate superconductors
Based on the NMR measurements on BiSrLaCuO
(La-Bi2201) in strong magnetic fields, we identify the non-superconducting
pseudogap phase in the cuprates as a Luttinger-volume violating Fermi liquid
(LvvFL). This state is a zero temperature quantum liquid that does not break
translational symmetry, and yet, the Fermi surface encloses a volume smaller
than the large one given by the Luttinger theorem. The particle number enclosed
by the small Fermi surface in the LvvFL equals the doping level , not the
total electron number . Both the phase string theory and the dopon
theory are introduced to describe the LvvFL. For the dopon theory, we can
obtain a semi-quantitative agreement with the NMR experiments.Comment: The final version in PR
Current status and legal/ethical problems in the research use of the tissues of aborted human fetuses in Japan
To date, there is no law regulating the research use of human aborted fetuses in Japan. The aim was to review the current status with historical background and legal/ethical problems limiting the research use of the tissues of aborted human fetuses. We reviewed literature via PubMed, Web of Science, Scopus, Japana Centra Revuo Medicina and CiNii, reports from various committees and research groups from Ministry of Health, Labour and Welfare (MHLW), and domestic books. Aborted human fetal tissues used for research purposes were first documented in the 1920s. The first guideline, the Peel Code was released in 1972. Since then, in Western countries, the research use of aborted fetuses has been less restricted compared with that of embryos, due to the following guidelines outlined by expert groups. Currently, aborted fetal tissues are commercially available for research purposes in the United States. In Japan, only four indications are presented in “a public statement permitting research use of deceased fetuses' and ‘neonates’ organs, etc.” (1987). In the 2000s, expert committees of the MHLW concluded that research use of human aborted fetuses should be discontinued, and that comprehensive rules and independent regulations should be implemented. This issue has not been discussed in the Japanese legislature since 2003. Establishment of laws and guidelines for this issue is insufficient not only in Japan but also in other countries. It is important to secure transparency for making laws and guidelines and in obtaining public understanding
Enhancing the Superconducting Transition Temperature due to Strong-Coupling Effect under Antiferromagnetic Spin Fluctuations in CeRh1-xIrxIn5 : 115In-NQR Study
We report on systematic evolutions of antiferromagnetic (AFM) spin
fluctuations and unconventional superconductivity (SC) in heavy-fermion (HF)
compounds CeRhIrIn via In
nuclear-quadrupole-resonance (NQR) experiment. The measurements of nuclear
spin-lattice relaxation rate have revealed the marked development of
AFM spin fluctuations as a consequence of approaching an AFM ordered state with
increasing Rh content. Concomitantly the superconducting transition temperature
and the energy gap increase drastically from K and in CeIrIn up to K and in
CeRhIrIn, respectively. The present work suggests that the
AFM spin fluctuations in close proximity to the AFM quantum critical point are
indeed responsible for the onset of strong-coupling unconventional SC with the
line node in the gap function in HF compounds.Comment: 4pages,5figures,to appear in Phys. Rev. Let
Carrier-Concentration Dependence of the Pseudogap Ground State of Superconducting Bi2Sr2-xLaxCuO6+delta Revealed by 63,65Cu-Nuclear Magnetic Resonance in Very High Magnetic Fields
We report the results of the Knight shift by 63,65Cu-nuclear-magnetic
resonance (NMR) measurements on single-layered copper-oxide
Bi2Sr2-xLaxCuO6+delta conducted under very high magnetic fields up to 44 T. The
magnetic field suppresses superconductivity completely and the pseudogap ground
state is revealed. The 63Cu-NMR Knight shift shows that there remains a finite
density of states (DOS) at the Fermi level in the zero-temperature limit, which
indicates that the pseudogap ground state is a metallic state with a finite
volume of Fermi surface. The residual DOS in the pseudogap ground state
decreases with decreasing doping (increasing x) but remains quite large even at
the vicinity of the magnetically ordered phase of x > 0.8, which suggests that
the DOS plunges to zero upon approaching the Mott insulating phase.Comment: 4 pages, 5 figures, to appear in Phys. Rev. Let
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