7,825 research outputs found
Predicting Mercury's Precession using Simple Relativistic Newtonian Dynamics
We present a new simple relativistic model for planetary motion describing
accurately the anomalous precession of the perihelion of Mercury and its
origin. The model is based on transforming Newton's classical equation for
planetary motion from absolute to real spacetime influenced by the
gravitational potential and introducing the concept of influenced direction.Comment: 5 page
Predicting the relativistic periastron advance of a binary without curving spacetime
Relativistic Newtonian Dynamics, the simple model used previously for
predicting accurately the anomalous precession of Mercury, is now applied to
predict the periastron advance of a binary. The classical treatment of a binary
as a two-body problem is modified to account for the influence of the
gravitational potential on spacetime. Without curving spacetime, the model
predicts the identical equation for the relativistic periastron advance as the
post-Newtonian approximation of general relativity formalism thereby providing
further substantiation of this model.Comment: 6 pages, 2 figure
Device-spectroscopy of magnetic field effects in a polyfluorene organic light-emitting diode
We perform charge-induced absorption and electroluminescence spectroscopy in
a polyfluorene organic magnetoresistive device. Our experiments allow us to
measure the singlet exciton, triplet exciton and polaron densities in a live
device under an applied magnetic field, and to distinguish between three
different models that were proposed to explain organic magnetoresistance. These
models are based on different spin-dependent interactions, namely exciton
formation, triplet exciton-polaron quenching and bipolaron formation. We show
that the singlet exciton, triplet exciton and polaron densities and
conductivity all increase with increasing magnetic field. Our data are
inconsistent with the exciton formation and triplet-exciton polaron quenching
models.Comment: 4 pages, two figure
Hyperfine interaction and magnetoresistance in organic semiconductors
We explore the possibility that hyperfine interaction causes the recently
discovered organic magnetoresistance (OMAR) effect. Our study employs both
experiment and theoretical modelling. An excitonic pair mechanism model based
on hyperfine interaction, previously suggested by others to explain magnetic
field effects in organics, is examined. Whereas this model can explain a few
key aspects of the experimental data, we, however, uncover several fundamental
contradictions as well. By varying the injection efficiency for minority
carriers in the devices, we show experimentally that OMAR is only weakly
dependent on the ratio between excitons formed and carriers injected, likely
excluding any excitonic effect as the origin of OMAR.Comment: 10 pages, 7 figures, 1 tabl
Rapid Cooling of the Neutron Star in Cassiopeia A Triggered by Neutron Superfluidity in Dense Matter
We propose that the observed cooling of the neutron star in Cassiopeia A is
due to enhanced neutrino emission from the recent onset of the breaking and
formation of neutron Cooper pairs in the 3P2 channel. We find that the critical
temperature for this superfluid transition is ~0.5x10^9 K. The observed
rapidity of the cooling implies that protons were already in a superconducting
state with a larger critical temperature. Our prediction that this cooling will
continue for several decades at the present rate can be tested by continuous
monitoring of this neutron star.Comment: Revised version, to be published in Phys. Rev. Let
On the and as Bound States and Approximate Nambu-Goldstone Bosons
We reconsider the two different facets of and mesons as
bound states and approximate Nambu-Goldstone bosons. We address several topics,
including masses, mass splittings between and and between and
, meson wavefunctions, charge radii, and the wavefunction overlap.Comment: 15 pages, late
Magnetic Properties of a Quantum Ferrimagnet: NiCu(pba)(D_2O)_3 . 2D_2O
We report the results of magnetic measurements on a powder sample of
NiCu(pba)(D_2O)_3 \cdot 2D_2OS\chi\chi TT\chi TJ/k_B=121
K^{2+}^{2+}g_{Ni}g_{Cu}\chi T$ at low temperatures
is reproduced fairly well by the calculation for the same ferrimagnetic model.Comment: 7pages, 4 postscript figures, usues REVTEX. appear in J. Phys. Soc.
Jpn vol 67 No.7 (1998
Poisson equation and self-consistent periodical Anderson model
We show that the formally exact expression for the free energy (with a
non-relativistic Hamiltonian) for the correlated metal generates the Poisson
equation within the saddle-point approximation for the electric potential,
where the charge density automatically includes correlations. In this
approximation the problem is reduced to the self-consistent periodical Anderson
model (SCPAM). The parameter of the mixing interaction in this formulation have
to be found self-consistently together with the correlated charge density. The
factors, calculated by Irkhin, for the mixing interaction, which reflect the
structure of the many-electron states of the \f-ion involved, arise
automatically in this formulation and are quite sensitive to the specific
element we are interested in. We also discuss the definitions of the mixing
interaction for the mapping from ab initio to model calculations.Comment: 25 pages, no figure
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