2,742 research outputs found
Electric Dipole Moments of Neutron-Odd Nuclei
The electric dipole moments (EDMs) of neutron-odd nuclei with even protons
are systematically evaluated. We first derive the relation between the EDM and
the magnetic moment operators by making use of the core polarization scheme.
This relation enables us to calculate the EDM of neutron-odd nuclei without any
free parameters. From this calculation, one may find the best atomic system
suitable for future EDM experiments.Comment: 4 page
Particular Integrability and (Quasi)-exact-solvability
A notion of a particular integrability is introduced when two operators
commute on a subspace of the space where they act. Particular integrals for
one-dimensional (quasi)-exactly-solvable Schroedinger operators and
Calogero-Sutherland Hamiltonians for all roots are found. In the classical case
some special trajectories for which the corresponding particular constants of
motion appear are indicated.Comment: 13 pages, typos correcte
A two dimensional model for ferromagnetic martensites
We consider a recently introduced 2-D square-to-rectangle martensite model
that explains several unusual features of martensites to study ferromagnetic
martensites. The strain order parameter is coupled to the magnetic order
parameter through a 4-state clock model. Studies are carried out for several
combinations of the ordering of the Curie temperatures of the austenite and
martensite phases and, the martensite transformation temperature. We find that
the orientation of the magnetic order which generally points along the short
axis of the rectangular variant, changes as one crosses the twin or the
martensite-austenite interface. The model shows the possibility of a subtle
interplay between the growth of strain and magnetic order parameters as the
temperature is decreased. In some cases, this leads to qualitatively different
magnetization curves from those predicted by earlier mean field models.
Further, we find that strain morphology can be substantially altered by the
magnetic order. We have also studied the dynamic hysteresis behavior.
The corresponding dissipation during the forward and reverse cycles has
features similar to the Barkhausen's noise.Comment: 9 pages, 11 figure
Periodically modulated geometric and electronic structure of graphene on Ru(0001)
We report here on a method to fabricate and characterize highly perfect,
periodically rippled graphene monolayers and islands, epitaxially grown on
single crystal metallic substrates under controlled UHV conditions. The
periodicity of the ripples is dictated by the difference in lattice parameters
of graphene and substrate, and, thus, it is adjustable. We characterize its
perfection at the atomic scale by means of STM and determine its electronic
structure in the real space by local tunnelling spectroscopy. There are
periodic variations in the geometric and electronic structure of the graphene
monolayer. We observe inhomogeneities in the charge distribution, i.e a larger
occupied Density Of States at the higher parts of the ripples. Periodically
rippled graphene might represent the physical realization of an ordered array
of coupled graphene quantum dots. The data show, however, that for rippled
graphene on Ru(0001) both the low and the high parts of the ripples are
metallic. The fabrication of periodically rippled graphene layers with
controllable characteristic length and different bonding interactions with the
substrate will allow a systematic experimental test of this fundamental
problem.Comment: 12 pages. Contribution to the topical issue on graphene of
Semiconductor Science and Technolog
Chemical potential shift and spectral weight transfer in PrCaMnO revealed by photoemission spectroscopy
We have studied the chemical potential shift and changes in the electronic
density of states near the Fermi level () as a function of carrier
concentration in PrCaMnO (PCMO, ) through
the measurements of photoemission spectra. The results showed that the chemical
potential shift was suppressed for x \agt 0.3, where the charge exchange
(CE)-type antiferromagnetic charge-ordered state appears at low temperatures.
We consider this observation to be related to charge self-organization such as
stripe formation on a microscopic scale in this composition range. Together
with the previous observation of monotonous chemical potential shift in
LaSrMnO, we conclude that the tendency toward the charge
self-organization increases with decreasing bandwidth. In the valence band,
spectral weight of the Mn 3 electrons in PCMO was transferred from
1 eV below to the region near with hole doping, leading to a
finite intensity at even in the paramagnetic insulating phase for x \agt
0.3, probably related with the tendency toward charge self-organization. The
finite intensity at in spite of the insulating transport behavior is
consistent with fluctuations involving ferromagnetic metallic states.Comment: 6 pages, 5 figure
A narrative review comparing clinical effectiveness of commonly used uterine balloon tamponade devices for postpartum haemorrhage management in India
Background: World Health Organisation recommends using Uterine Balloon Tamponade (UBT) for refractory atonic postpartum haemorrhage (PPH) management provided treatment protocols and surgical recourse is possible. Methods: This review collated literature from three electronic databases between January 2010 to December 2019 to compare clinical effectiveness, safety and use related parameters for condom-UBT, Bakri balloon and Every Second Matters (ESM) UBT devices used in India. Results: Thirty-three eligible studies reported effectiveness in managing all PPH causes ranging from 84.2% to 98.3% for condom-UBT and from 65.3% to 94.8% for Bakri-UBT. Three ESM-UBT studies reported PPH survival rates of 94% to 97.4%. Mean UBT effectiveness in controlling atonic PPH was 92.3% for condom-UBT, 84.3% for Bakri-UBT and 97.3% for ESM-UBT. Condom-UBT and Bakri-UBT were comparable across parameters whereas limited ESM-UBT evidence reported success in preventing maternal deaths. Conclusions: For limitations and heterogeneity in methodology and outcome parameters with existing evidence, a robust comparative RCT between UBT devices in India is recommended
Perturbation Theory on the Transition Temperature and Electronic Properties of Organic Superconductor
We study the superconducting transition temperature and the electronic
properties of the metallic phase of -type (BEDT-TTF)X which shows
unconventional properties in experiments, on the basis of the third order
perturbation theory for a simple effective Hubbard model of a nearly triangular
lattice. Appropriate transition temperatures and symmetry of the
gap function are obtained in good agreement with experimental results. We also
calculate the transition temperature by the fluctuation-exchange
approximation(FLEX) in order to compare the two approaches; FLEX gives higher
transition temperatures rather than the perturbation approach. However, it is
also found that the vertex corrections, which are ignored in FLEX, have a
crucial effect on for strongly frustrated systems. The density of
states and the normal self-energy calculated in this perturbation scheme show
the nature of the conventional Fermi liquid near the Mott-insulator. Thus, our
perturbation approach is applicable to the conventional metallic phase of this
compound, while it cannot explain the (pseudo-)spin gap phenomenon which
signals the non-Fermi liquid
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