943 research outputs found
Topological superconductivity in bilayer Rashba system
We theoretically study a possible topological superconductivity in the
interacting two layers of Rashba systems, which can be fabricated by the
hetero-structures of semiconductors and oxides. The hybridization, which
induces the gap in the single particle dispersion, and the electron-electron
interaction between the two layers leads to the novel phase diagram of the
superconductivity. It is found that the topological superconductivity {\it
without breaking time-reversal symmetry} is realized when (i) the Fermi energy
is within the hybridization gap, and (ii) the inter-layer interaction is
repulsive, both of which can be satisfied in realistic systems. Edge channels
are studied in a tight-binding model numerically, and the several predictions
on experiments are also given.Comment: 5 page
Higgs Mass and Muon Anomalous Magnetic Moment in Supersymmetric Models with Vector-Like Matters
We study the muon anomalous magnetic moment (muon g-2) and the Higgs boson
mass in a simple extension of the minimal supersymmetric (SUSY) Standard Model
with extra vector-like matters, in the frameworks of gauge mediated SUSY
breaking (GMSB) models and gravity mediation (mSUGRA) models. It is shown that
the deviation of the muon g-2 and a relatively heavy Higgs boson can be
simultaneously explained in large tan-beta region. (i) In GMSB models, the
Higgs mass can be more than 135 GeV (130 GeV) in the region where muon g-2 is
consistent with the experimental value at the 2 sigma (1 sigma) level, while
maintaining the perturbative coupling unification. (ii) In the case of mSUGRA
models with universal soft masses, the Higgs mass can be as large as about 130
GeV when muon g-2 is consistent with the experimental value at the 2 sigma
level. In both cases, the Higgs mass can be above 140 GeV if the g-2 constraint
is not imposed.Comment: 26 pages; 7 figures; corrected typos; minor change
Holographic Lattices, Dimers, and Glasses
We holographically engineer a periodic lattice of localized fermionic
impurities within a plasma medium by putting an array of probe D5-branes in the
background produced by N D3-branes. Thermodynamic quantities are computed in
the large N limit via the holographic dictionary. We then dope the lattice by
replacing some of the D5-branes by anti-D5-branes. In the large N limit, we
determine the critical temperature below which the system dimerizes with bond
ordering. Finally, we argue that for the special case of a square lattice our
system is glassy at large but finite N, with the low temperature physics
dominated by a huge collection of metastable dimerized configurations without
long-range order, connected only through tunneling events.Comment: 20 pages, 7 figures; v2: minor revisions mad
Identification and Evaluation of Viable Market Opportunities for Organically-Grown Aquatic Products: Results from the Focus Group Meetings
Livestock Production/Industries, Marketing,
Moments of a single entry of circular orthogonal ensembles and Weingarten calculus
Consider a symmetric unitary random matrix
from a circular orthogonal ensemble. In this paper, we study moments of a
single entry . For a diagonal entry we give the explicit
values of the moments, and for an off-diagonal entry we give leading
and subleading terms in the asymptotic expansion with respect to a large matrix
size . Our technique is to apply the Weingarten calculus for a
Haar-distributed unitary matrix.Comment: 17 page
Instanton Calculus of Lifshitz Tails
For noninteracting particles moving in a Gaussian random potential, there
exists a disagreement in the literature on the asymptotic expression for the
density of states in the tail of the band. We resolve this discrepancy. Further
we illuminate the physical facet of instantons appearing in replica and
supersymmetric derivations with another derivation employing a Lagrange
multiplier field.Comment: 5 page
Contracted Representation of Yang's Space-Time Algebra and Buniy-Hsu-Zee's Discrete Space-Time
Motivated by the recent proposition by Buniy, Hsu and Zee with respect to
discrete space-time and finite spatial degrees of freedom of our physical world
with a short- and a long-distance scales, and we reconsider the
Lorentz-covariant Yang's quantized space-time algebra (YSTA), which is
intrinsically equipped with such two kinds of scale parameters, and
. In accordance with their proposition, we find the so-called contracted
representation of YSTA with finite spatial degrees of freedom associated with
the ratio , which gives a possibility of the divergence-free
noncommutative field theory on YSTA. The canonical commutation relations
familiar in the ordinary quantum mechanics appear as the cooperative
Inonu-Wigner's contraction limit of YSTA, and $R \to \infty.
Lepton Flavor Violation and Cosmological Constraints on R-parity Violation
In supersymmetric standard models R-parity violating couplings are severely
constrained, since otherwise they would erase the existing baryon asymmetry
before the electroweak transition. It is often claimed that this cosmological
constraint can be circumvented if the baryon number and one of the lepton
flavor numbers are sufficiently conserved in these R-parity violating
couplings, because B/3-L_i for each lepton flavor is separately conserved by
the sphaleron process. We discuss the effect of lepton flavor violation on the
B-L conservation, and show that even tiny slepton mixing angles \theta_{12}
\gsim {\cal O}(10^{-4}) and \theta_{23}, \theta_{13}\gsim {\cal O}(10^{-5})
will spoil the separate B/3-L_i conservation. In particular, if lepton flavor
violations are observed in experiments such as MEG and B-factories, it will
imply that all the R-parity violating couplings must be suppressed to avoid the
B-L erasure. We also discuss the implication for the decay of the lightest MSSM
particle at the LHC.Comment: 21 pages, 7 figures. v2: minor change
Near-Infrared Extinction in The Coalsack Globule 2
We have conducted J, H, and Ks imaging observations for the Coalsack Globule
2 with the SIRIUS infrared camera on the IRSF 1.4 m telescope at SAAO, and
determined the color excess ratio, E(J-H)/E(H-Ks). The ratio is determined in
the same photometric system as our previous study for the rho Oph and Cha
clouds without any color transformation; this enables us to directly compare
the near-infrared extinction laws among these regions. The current ratio
E(J-H)/E(H-Ks) = 1.91 +- 0.01 for the extinction range 0.5 < E(J-H) <1.8 is
significantly larger than the ratios for the rho Oph and Cha clouds
(E(J-H)/E(H-Ks) = 1.60-1.69). This ratio corresponds to a large negative index
alpha = 2.34 +- 0.01 when the wavelength dependence of extinction is
approximated by a power law which might indicate little growth of dust grains,
or larger abundance of dielectric non-absorbing components such as silicates,
or both in this cloud. We also confirm that the color excess ratio for the
Coalsack Globule 2 has a trend of increasing with decreasing optical depth,
which is the same trend as the rho Oph and Cha clouds have.Comment: 13 pages, 5 figures, and 2 tables, Ap
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