1,164 research outputs found
Nematic transition and highly two-dimensional superconductivity in BaTiBiO revealed by Bi-nuclear magnetic resonance/nuclear quadrupole resonance measurements
In this Rapid Communication, a set of Bi-nuclear magnetic resonance
(NMR)/nuclear quadrupole resonance (NQR) measurements has been performed to
investigate the physical properties of superconducting (SC) BaTiBiO
from a microscopic point of view. The NMR and NQR spectra at 5~K can be
reproduced with a non-zero in-plane anisotropic parameter , indicating
the breaking of the in-plane four-fold symmetry at the Bi site without any
magnetic order, i.e., `the electronic nematic state'. In the SC state, the
nuclear spin-lattice relaxation rate divided by temperature, , does not
change even below , while a clear SC transition was observed with a
diamagnetic signal. This observation can be attributed to the strong
two-dimensionality in BaTiBiO. Comparing the NMR/NQR results among
BaTiO ( = As, Sb, and Bi), it was found that the normal and SC
properties of BaTiBiO were considerably different from those of
BaTiSbO and BaTiAsO, which might explain the two-dome structure
of in this system.Comment: 5 pages, 6 figure
Coupled channel approach to strangeness S = -2 baryon-bayron interactions in Lattice QCD
The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3)
breaking are calculated for the first time by using the HAL QCD method extended
to coupled channel system in lattice QCD. The potential matrices are extracted
from the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge
configurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93
fm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the
quark mass dependence of the potential matrix in the baryon basis and in the
SU(3) basis are investigated.Comment: 17 pages, 15 figure
Low-energy excitations in a one-dimensional orthogonal dimer model with the Dzyaloshinski-Moriya interaction
Effects of the Dzyaloshinski-Moriya (DM) interaction on low-energy
excitations in a one-dimensional orthogonal-dimer model are studied by using
the perturbation expansions and the numerical diagonalization method. In the
absence of the DM interaction, the triplet excitations show two flat spectra
with three-fold degeneracy, which are labeled by magnetization .
These spectra split into two branches with M=0 and with by
switching-on of the DM interaction and besides the curvature appears in the
triplet excitations with more strongly than those of M=0.Comment: 4 pages, 2 figures, Proceeding for The 9th ISSP International
Symposium (ISSP-9) on Quantum Condensed System (Nov. 2004
On the Phononic Bandgap of Carbon Nanotubes
On the phononic bandgap of carbon nanotubes (CNTs), we show in what chirality CNTs have
phononic bandgaps and its dependence on the diameters of CNTs. We find that, though the rule where CNTs have phononic bandgaps is the same as in the electronic structure case, the diameter dependence is different. The phononic bandgaps of the zigzag-CNTs reveal “three” kinds of diameter dependence due to the anisotropy of graphene phonon band around the K point in k-space. We also show the crossover from one- to two-dimensional characteristics in phononic bandgaps
How Cervical Reconstruction Surgery Affects Global Spinal Alignment.
BACKGROUND:There have been no reports describing how cervical reconstruction surgery affects global spinal alignment (GSA). OBJECTIVE:To elucidate the effects of cervical reconstruction for GSA through a retrospective multicenter study. METHODS:Seventy-eight patients who underwent cervical reconstruction surgery for cervical kyphosis were divided into a Head-balanced group (n = 42) and a Trunk-balanced group (n = 36) according to the values of the C7 plumb line (PL). We also divided the patients into a cervical sagittal balanced group (CSB group, n = 18) and a cervical sagittal imbalanced group (CSI group, n = 60) based on the C2 PL-C7 PL distance. Various sagittal Cobb angles and the sagittal vertical axes were measured before and after surgery. RESULTS:Cervical alignment was improved to achieve occiput-trunk concordance (the distance between the center of gravity [COG] PL, which is considered the virtual gravity line of the entire body, and C7 PL < 30 mm) despite the location of COG PL and C7PL. A subsequent significant change in thoracolumbar alignment was observed in Head-balanced and CSI groups. However, no such significant change was observed in Trunk-balanced and CSB groups. We observed 1 case of transient and 1 case of residual neurological worsening. CONCLUSION:The primary goal of cervical reconstruction surgery is to achieve occiput-trunk concordance. Once it is achieved, subsequent thoracolumbar alignment changes occur as needed to harmonize GSA. Cervical reconstruction can restore both cervical deformity and GSA. However, surgeons must consider the risks and benefits in such challenging cases
Hadron-Hadron Interactions from Imaginary-time Nambu-Bethe-Salpeter Wave Function on the Lattice
Imaginary-time Nambu-Bethe-Salpeter (NBS) wave function is introduced to
extend our previous approach for hadron-hadron interactions on the lattice.
Scattering states of hadrons with different energies encoded in the NBS
wave-function are utilized to extract non-local hadron-hadron potential. "The
ground state saturation", which is commonly used in lattice QCD but is hard to
be achieved for multi-baryons, is not required. We demonstrate that the present
method works efficiently for the nucleon-nucleon interaction (the potential and
the phase shift) in the 1S_0 channel.Comment: 13 pages, 6 figure
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