41,504 research outputs found
Majorana fermion chain at the Quantum Spin Hall edge
We study a realization of a 1d chain of Majorana bound states at the
interfaces between alternating ferromagnetic and superconducting regions at a
quantum spin Hall insulator edge. In the limit of well separated Majoranas, the
system can be mapped to the transverse field Ising model. The disordered
critical point can be reached by tuning the relative magnitude or phases of the
ferromagnetic and superconducting order parameters. We compute the voltage
dependence of the tunneling current from a metallic tip into the Majorana chain
as a direct probe of the random critical state.Comment: 5 pages, 3 figure
Calculation of the energy levels of Ge, Sn, Pb and their ions in the approximation
Energy levels of germanium, tin and lead together with their single, double
and triple ionized positive ions have been calculated using the
approximation suggested in the previous work (Dzuba, physics/0501032) (M=4 -
number of valence electrons). Initial Hartree-Fock calculations are done for
the quadruply ionized ions with all valence electrons removed. The core-valence
correlations are included beyond the second-order of the many-body perturbation
theory. Interaction between valence electrons is treated by means of the
configuration interaction technique. It is demonstrated that accurate treatment
of the core-valence correlations lead to systematic improvement of the accuracy
of calculations for all ions and neutral atoms.Comment: 7 pages, 3 figures, 3 tables; submitted to Phys. Rev.
Constraints on Hidden Photon Models from Electron g-2 and Hydrogen Spectroscopy
The hidden photon model is one of the simplest models which can explain the
anomaly of the muon anomalous magnetic moment (g-2). The experimental
constraints are studied in detail, which come from the electron g-2 and the
hydrogen transition frequencies. The input parameters are set carefully in
order to take dark photon contributions into account and to prevent the
analysis from being self-inconsistent. It is shown that the new analysis
provides a constraint severer by more than one order of magnitude than the
previous result.Comment: 18 pages, 2 figures, 1 table. v2: minor correction
HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution
The author has identified the following significant results. To investigate the general relationship between surface temperature and soil moisture profiles, a series of model calculations were carried out. Soil temperature profiles were calculated during a complete diurnal cycle for a variety of moisture profiles. Preliminary results indicate the surface temperature difference between two sites measured at about 1400 hours is related to the difference in soil moisture within the diurnal damping depth (about 50 cm). The model shows this temperature difference to vary considerably throughout the diurnal cycle
Ablation of murine jejunal crypts by alkylating agents.
The gut microcolony assay has been used to measure damage to intestinal crypts by single and split doses of 3 alkylating agents: mechlorethamine hydrochloride (HN2), bis-chloroethyl-nitrosourea (BCNU) and isopropyl methane sulphonate (IMS). The single-dose survival curves for whole crypts were distinguished by extrapolation numbers (3.0, 176 and 1.5 respectively) that were lower than most previously published values for assay by irradiation. Significant sparing of crypts occurred when doses of HN2 or BCNU, but not IMS, were given in 2 equal fractions separated by more than 2 h. Deduced D0 values for those cells from which crypts regenerate were 1.9 mg/kg HN2, 19 mg/kg BCNU and 487 mg/kg IMS
Irrigation management with remote sensing
Two visible/near IR hand held radiometers and a hand held thermoradiometer were used along with soil moisture and lysimetric measurements in a study of soil moisture distribution in afalfa fields on the Navajo Indian Irrigation Project near farmington, New Mexico. Radiances from irrigated plots were measured and converted to reflectances. Surface soil water contents (o cm to 4 cm) were determined gravimetrically on samples collected at the same time as the spectral measurements. The relationship between the spectral measurements and the crop coefficient were evaluated to demonstrate potential for using spectral measurement to estimate crop coefficient
Emittance growth mechanisms in the Tevatron beams
In this article we present results of emittance growth measurements in the
Tevatron beams. Several mechanisms leading to transverse and longitudinal
diffusions are analyzed and their contributions estimated.Comment: 7 p
Calculations of energy levels and lifetimes of low-lying states of barium and radium
We use the configuration interaction method and many-body perturbation theory
to perform accurate calculations of energy levels, transition amplitudes, and
lifetimes of low-lying states of barium and radium. Calculations for radium are
needed for the planning of measurements of parity and time invariance violating
effects which are strongly enhanced in this atom. Calculations for barium are
used to control the accuracy of the calculations.Comment: 8 page
Preliminary report on Skylab S-193 Radscat measurements of Hurricane Ava
The author has identified the following significant results. The Skylab RADSCAT instrument S-193 was operated on 6 June 1973 while the spacecraft flew past Hurricane Ava in the eastern Pacific Ocean. Scatterometer returns at all polarizations and radiometer measurements were obtained from a section through the storm with winds up to 48 knots at 52 deg incident angle and 35 knots at 45.5 deg incident angle. These first hurricane scatterometer measurements indicate reasonable correlation between wind speed and backscatter, with horizontal response much stronger than the vertical response at 52 deg. Each of the sections through the hurricane contains an as yet unexplained dip in cross section at a point 200 to 300 km prior to passing the eye. The response at a point where the radiometer signal's dramatic increase indicates strong rain is also accompanied by a strong increase in the backscattered signal. No attempt has been made to make a thorough correlation of radiometric response with wind speed, but the atmospheric contribution to the radiometer signal is quite apparent
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