9,491 research outputs found
Evaluation of Half-metallic Antiferromagnetism in CrFeO ({}=La, Sr
The nearly well-ordered double perovskite LaCrFeO has been
synthesized recently. Contrary to previous theoretical predictions, but in
agreement with experimental observations, our first principle calculations
indicate an insulating ferrimagnet LaCrFeO with antialigned S=3/2
Cr and S=5/2 Fe ions,using the local spin density approximation
(LSDA), a correlated band theory LDA+U, and a semilocal functional modified
Becke-Johnson method. Additionally, we investigated the double perovskite
SrCrFeO, which is as yet unsynthesized. In LSDA calculations, this
system shows formally tetravalent Cr and Fe ions both having antialigned =1
moments, but is a simple metal. Once applying on-site Coulomb repulsion U on
both Cr and Fe ions, this system becomes half-metallic and the moment of Fe is
substantially reduced, resulting in zero net moment. These results are
consistent with our fixed spin moment studies. Our results suggest a precisely
compensated half-metallic SrCrFeO.Comment: 7 page
Temperature-dependent errors in nuclear lattice simulations
We study the temperature dependence of discretization errors in nuclear
lattice simulations. We find that for systems with strong attractive
interactions the predominant error arises from the breaking of Galilean
invariance. We propose a local "well-tempered" lattice action which eliminates
much of this error. The well-tempered action can be readily implemented in
lattice simulations for nuclear systems as well as cold atomic Fermi systems.Comment: 33 pages, 17 figure
Symmetry and Radiatively Generated Leptogenesis
We consider a symmetry in neutrino sectors realized at GUT scale
in the context of a seesaw model. In our scenario, the exact
symmetry realized in the basis where the charged lepton and heavy Majorana
neutrino mass matrices are diagonal leads to vanishing lepton asymmetries. We
find that, in the minimal supersymmetric extension of the seesaw model with
large , the renormalization group (RG) evolution from GUT scale to
seesaw scale can induce a successful leptogenesis even without introducing any
symmetry breaking terms by hand, whereas such RG effects lead to tiny
deviations of and from and zero,
respectively. It is shown that the right amount of the baryon asymmetry
can be achieved via so-called resonant leptogenesis, which can be
realized at rather low seesaw scale with large in our scenario so
that the well-known gravitino problem is safely avoided.Comment: 17 pages, 5 figures. Published in PR
Prevention of Pinking, Off-Odor, and Lipid Oxidation in Irradiated Pork Loin Using Double-Packaging
Lipid oxidation, color, volatiles, and sensory evaluation of double-packaged pork loin were determined to establish a modified packaging method that can improve the quality of irradiated pork loins. Vacuum-packaged irradiated samples produced dimethyl sulfide and dimethyl disulfide responsible for irradiation off-odor, whereas lipid oxidation was promoted under aerobic conditions. Exposing doublepackaged irradiated pork to aerobic conditions for 1 to 3 d was effective in controlling both lipid oxidation and irradiation off-odor, regardless of packaging sequence. Sensory panels could distinguish the decrease in irradiation off-odor intensities by modifying packaging method. However, carbon monoxide-heme pigments, responsible for the increased redness by irradiation, were not effectively controlled by double packaging alone
SO/Sp Monopoles and Branes with Orientifold 3 Plane
We study BPS monopoles in 4 dimensional N=4 SO(N) and super
Yang-Mills theories realized as the low energy effective theory of
(physical and its mirror) parallel D3 branes and an {\it Orientifold 3 plane}
with D1 branes stretched between them in type IIB string theory. Monopoles on
D3 branes give the natural understanding by embedding in SU(N) through the
constraints on both the asymptotic Higgs field (corresponding to the horizontal
positions of D3 branes) and the magnetic charges (corresponding to the number
of D1 branes) imposed by the O3 plane. The compatibility conditions of Nahm
data for monopoles for these groups can be interpreted very naturally through
the D1 branes in the presence of O3 plane.Comment: 18 pages, Latex with RevTex, 1 table, 4 figures, v2: Clarified the
introduction and improved on the supersymmetric theory on D1 branes in page 7
and 8 and this final version to appear in Phys.Rev.
Pairing in the quantum Hall system
We find an analogy between the single skyrmion state in the quantum Hall
system and the BCS superconducting state and address that the quantum
mechanical origin of the skyrmion is electronic pairing. The skyrmion phase is
found to be unstable for magnetic fields above the critical field at
temperature , which is well represented by the relation .Comment: revtex, two figures, to appear in Phys. Rev. B (Rapid Communications
J. Craig WheelerThe Nature and Consequences of Cosmological Halo Formation: Dark Matter and the Dark Ages
First, I am deeply indebted to my wife, Younga, who had an uneasy summer season due to her guilt of having an aging graduate student as her hubby. At this right moment my writing this acknowledgment, she may be preparing warm breakfast for two children. I am guilty of depriving her of all the summer fun. Younga, I met you only seven years ago, but I should have met you much earlier. When you are away, I think about you. When you are near, I see you. You are my heart, my soul, my canvas, my wine, my potato chip, my sun. I appreciate my Parents-in-law for accepting me as Son-in-law, and supporting me. I wish to thank Father and Mother, who have raised and guided me on this hostile planet Earth. Hatred and poverty caused by its own inhabitants is the most difficult thing I can bear. Without them, I could not have survived it. Their life was a grand symphony. Now, here is my humble rose to you. My lovely kids! How pretty (and noisy) you are! Please grow healthy
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