2,343 research outputs found
Lambda and Anti-Lambda Hypernuclei in Relativistic Mean-field Theory
Several aspects about -hypernuclei in the relativistic mean field
theory, including the effective -nucleon coupling strengths based on
the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic
moment and -hypernuclei, have been presented. The effect of tensor
coupling in -hypernuclei and the impurity effect of to
nuclear structure have been discussed in detail.Comment: 8 pages, 2 figures, Proceedings of the Sendai International Symposium
"Strangeness in Nuclear and Hadronic Systems SENDAI08
Kondo correlation and spin-flip scattering in spin-dependent transport through a quantum dot coupled to ferromagnetic leads
We investigate the linear and nonlinear dc transport through an interacting
quantum dot connected to two ferromagnetic electrodes around Kondo regime with
spin-flip scattering in the dot. Using a slave-boson mean field approach for
the Anderson Hamiltonian having finite on-site Coulomb repulsion, we find that
a spin-flip scattering always depresses the Kondo correlation at arbitrary
polarization strength in both parallel and antiparallel alignment of the lead
magnetization and that it effectively reinforces the tunneling related
conductance in the antiparallel configuration. For systems deep in the Kondo
regime, the zero-bias single Kondo peak in the differential conductance is
split into two peaks by the intradot spin-flip scattering; while for systems
somewhat further from the Kondo center, the spin-flip process in the dot may
turn the zero-bias anomaly into a three-peak structure.Comment: 4 pages, 2 figure
Atomically flat interface between a single-terminated LaAlO3 substrate and SrTiO3 thin film is insulating
The surface termination of (100)-oriented LaAlO3 (LAO) single crystals was
examined by atomic force microscopy and optimized to produce a
single-terminated atomically flat surface by annealing. Then the atomically
flat STO film was achieved on a single-terminated LAO substrate, which is
expected to be similar to the n-type interface of two-dimensional electron gas
(2DEG), i.e., (LaO)-(TiO2). Particularly, that can serve as a mirror structure
for the typical 2DEG heterostructure to further clarify the origin of 2DEG.
This newly developed interface was determined to be highly insulating.
Additionally, this study demonstrates an approach to achieve atomically flat
film growth based on LAO substrates.Comment: 4 pages, 3 figure
Magnetic-field induced resistivity minimum with in-plane linear magnetoresistance of the Fermi liquid in SrTiO3-x single crystals
We report novel magnetotransport properties of the low temperature Fermi
liquid in SrTiO3-x single crystals. The classical limit dominates the
magnetotransport properties for a magnetic field perpendicular to the sample
surface and consequently a magnetic-field induced resistivity minimum emerges.
While for the field applied in plane and normal to the current, the linear
magnetoresistance (MR) starting from small fields (< 0.5 T) appears. The large
anisotropy in the transverse MRs reveals the strong surface interlayer
scattering due to the large gradient of oxygen vacancy concentration from the
surface to the interior of SrTiO3-x single crystals. Moreover, the linear MR in
our case was likely due to the inhomogeneity of oxygen vacancies and oxygen
vacancy clusters, which could provide experimental evidences for the unusual
quantum linear MR proposed by Abrikosov [A. A. Abrikosov, Phys. Rev. B 58, 2788
(1998)].Comment: 5 pages, 4 figure
Quark Mass Ratios in ChPT with the Difference of Quark Condensates Considered
The chiral effective Lagrangian for pseudoscalar nonet is constructed in
consideration of isospin breaking. And the difference of quark condensates is
taken accounted. The SU(3) singlet eta0 is not taken as Goldstone-boson. The
mixing with and without isospin symmetry is considered. The quark mass ratios
are obtained through solving the mass equations of mesons. We estimate the
change of quark mass ratios according to the change of the masses of pion+ and
kaon+ to see how the electromagnetic corrections affect our results. It turn
out that massless up quark is possible. The upper limit for mu/md is around
0.39. 2ms/(mu+md)=24.23~25.12. The values for quark condensate ratios and other
constants are limited in narrow ranges.Comment: 10 page
f(R) Gravities, Killing Spinor Equations, "BPS" Domain Walls and Cosmology
We derive the condition on f(R) gravities that admit Killing spinor equations
and construct explicit such examples. The Killing spinor equations can be used
to reduce the fourth-order differential equations of motion to the first order
for both the domain wall and FLRW cosmological solutions. We obtain exact "BPS"
domain walls that describe the smooth Randall-Sundrum II, AdS wormholes and the
RG flow from IR to UV. We also obtain exact smooth cosmological solutions that
describe the evolution from an inflationary starting point with a larger
cosmological constant to an ever-expanding universe with a smaller cosmological
constant. In addition, We find exact smooth solutions of pre-big bang models,
bouncing or crunching universes. An important feature is that the scalar
curvature R of all these metrics is varying rather than a constant. Another
intriguing feature is that there are two different f(R) gravities that give
rise to the same "BPS" solution. We also study linearized f(R) gravities in
(A)dS vacua.Comment: 37 pages, discussion on gravity trapping in RSII modified, typos
corrected, further comments and references added; version to appear in JHE
Spin and orbital angular momentum in gauge theories (II): QCD and nucleon spin structure
Parallel to the construction of gauge invariant spin and orbital angular
momentum for QED in paper (I) of this series, we present here an analogous but
non-trivial solution for QCD. Explicitly gauge invariant spin and orbital
angular momentum operators of quarks and gluons are obtained. This was
previously thought to be an impossible task, and opens a more promising avenue
towards the understanding of the nucleon spin structure.Comment: 3 pages, no figure; presented by F. Wang at NSTAR200
Carrier freeze-out induced metal-insulator transition in oxygen deficient SrTiO3 films
We report the optical, electrical transport, and magnetotransport properties
of high quality oxygen deficient SrTiO3 (STO) single crystal film fabricated by
pulsed laser deposition and reduced in the vacuum chamber. The oxygen vacancy
distribution in the thin film is expected to be uniform. By comparing the
electrical properties with oxygen deficient bulk STO, it was found that the
oxygen vacancies in bulk STO is far from uniform over the whole material. The
metal-insulator transition (MIT) observed in the oxygen deficient STO film was
found to be induced by the carrier freeze-out effect. The low temperature
frozen state can be re-excited by an electric field, Joule heating, and
surprisingly also a large magnetic field.Comment: 5 pages, 5 figure
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